Temperature Dependant Mixed Micellization Behavior of a

[Article] wwwwhxbpkueducn

物理化学学报(Wuli Huaxue Xuebao)

Acta Phys -Chim Sin 2014 30 (4) 699-707April

Received December 6 2013 Revised February 10 2014 Published on Web February 11 2014lowastCorresponding author Email malikrubgmailcom malik_rub2000yahoocom Tel +966-563671946

The project was supported by the Chemistry Department and Centre of Excellence for Advanced Materials Research King Abdulaziz University

Jeddah Saudi Arabia

copy Editorial office of Acta Physico-Chimica Sinica

doi 103866PKUWHXB201402112

Temperature Dependant Mixed Micellization Behavior of a Drug-AOTMixture in an Aqueous Medium

RUB Malik Abdul12 ASIRI Abdullah M12 KUMAR Dileep3 AZUM Naved12 KHAN Farah3

(1Chemistry Department King Abdulaziz University Jeddah-21589 Saudi Arabia2Center of Excellence for Advanced Materials Research King Abdulaziz University Jeddah-21589 Saudi Arabia

3Department of Chemistry Aligarh Muslim University Aligarh-202002 India)

Abstract The mixed micellization behavior of an amphiphilic antidepressant drug amitriptyline

hydrochloride (AMT) in the presence of the conventional anionic surfactant sodium bis(2-ethylhexyl)

sulfosuccinate (AOT) was studied at five different temperatures and compositions by the conductometric

technique The critical micelle concentration (cmc) and critical micelle concentration at the ideal state

(cmcid) values show mixed micelle formation between the components (ie drug and AOT) The micellar

mole fractions of the AOT (X1) values calculated using the Rubingh Motomura and Rodenas models show

a higher contribution of AOT in the mixed micelles The interaction parameter (β) is negative at all

temperatures and the compositions show attractive interactions between the components The activity

coefficients (f1 and f2) calculated using the different proposed models are always less than unity indicating

non- ideality in the systems The ΔGmӨ values were found to be negative for all the binary mixed systems

However ΔHmӨ values for the pure drug as well as the drug- AOT mixed systems are negative at lower

temperatures (29315- 30315 K) and positive at higher temperatures (30815 K and above) The ΔSmӨ

values are positive at all temperatures but their magnitude was higher at T=30815 K and above The

excess free energy of mixing (ΔGex) determined using the different proposed models also explains the

stability of the mixed micelles compared to the pure drug (AMT) and surfactant micelles

Key Words Antidepressant drug Amitriptyline hydrochloride cmc Interaction parameter

Thermodynamic parameters

1 IntroductionThe micellization of amphiphilic molecules (eg surfac-

tants drugs dyes) after a certain concentration called the criti-

cal micellar concentration (cmc) is an important solution prop-

erty which needs evaluation to know the existence of micelles

in solution as well as evaluating the thermodynamics of the

process which is essential for characterization and comparison

in the light of spontaneity and stability A variety of amphiphil-

ic drugs such as phenothiazines tranquillizers analgesics pep-

tides antibiotics tricyclic antidepressants etc are of varied

clinical uses1-4 They can be classified by virtue of their differ-

ent functional groups ie hydrophilic and hydrophobic These

groups are responsible for a drugprimes therapeutic properties Al-

though these drugs are amphiphilic in nature they are not lipo-

philic sufficiently to form vesicles or to act as their own carrier

In the present paper amitriptyline hydrochloride (3- (1011-

dihydro-5H-dibenzo [ad] cycloheptene-5-ylidene)-NN-dimeth-

yl-1-propanamine hydrochloride) drug used as a model is am-

phiphilic in nature The empirical formula of amitriptyline hy-

drochloride (AMT) is C20H23NHCl and its schematic presenta-

tion is shown in Scheme 1 It is white in color odorless and

crystalline compound which is freely soluble in water Its

mechanism of action on people is unknown AMT possesses a

planar rigid tricyclic ring system with a short alkyl amide

chain Planar rigid tricyclic ring behaves as hydrophobic part

and an alkyl amine side chain acts as hydrophilic head group

part for this reason this AMT drug aggregates in a surfactant

like manner It forms small aggregates of 6-12 drug mole-

cules5 AMT is an antidepressant drug It is thought that AMT

increases the activities and levels of certain chemicals in the

brain This can improve symptom of depression AMT is also

used to treat nocturnal enuresis Along with its needed effects

AMT may cause some unwanted effects To overcome the tox-

ic side effects of the drug and increase its bioavailability is to

699

Acta Phys -Chim Sin 2014 Vol30

use in association with different drug carrier systems which

may alter their chemical activity and pharmacological behav-

ior67 The development of such a drug carrier is still facing a

challenging problem because of its low water-solubility gener-

ally resulting in poor absorption and bioavailability which

leads to drug aggregation-related complications such as embo-

lism89 In addition such antidepressant drugs have been found

to interact with phospholipids of bio-membrane resulting in

their accumulation a condition referred to as phospholipido-

sis10 In view of this it necessitates the need of formulation of

AMT drug which might reduce its tendency to bind with phos-

pholipids without affecting its activity

In this regard surfactant micelles show some superior advan-

tages over other alternatives like soluble polymers and lipo-

somes11 Micellar systems can be used to solubilize poorly solu-

ble drugs and hence increase their bioavailability They can

stay in the body (blood) for a long time to provide gradual ac-

cumulation in the required area and also their sizes allow them

to accumulate in areas with leaky vasculature12

Therefore in search of enhanced utility and to provide fur-

ther input we have systematically studied the physicochemical

properties of AMT-AOT (sodium bis(2-ethylhexyl)-sulfosucci-

nate) mixed systems conductometrically in a very low concen-

tration range of AOT

AOT is a well-known and versatile anionic surfactant con-

taining two hydrophobic tails This typical molecular structure

of AOT may be responsible for its ability to form microemul-

sion and show rich phase behavior (Scheme 2) A number of

models eg Clintprimes13 Rubinghprimes14 Motomuraprimes15 and Rodenasprimes16

were used to obtain different parameters related to mixed mi-

celles The effect of temperature on micelle formation was also

studied which gives information about relative characterization

of amphiphile solutions This information is obtained from the

thermodynamic parameters of micelle formation ie standard

Gibbprimes energy (ΔGӨm) enthalpy (ΔHӨ

m) and entropy of micelliza-

tion (ΔSӨm) that quantify the relative importance of electrostatic

and hydrophobic interaction

2 Experimental21 Materials

Reagents used in this study are given here along with their

make and purity AMT (ge98) supplied by Sigma USA was

used as received Anionics surfactant AOT is Aldrich USA

product with ge97 purity was used without further purifica-

tion Water with a conductivity of 1times10-6-2times10-6 Ω-1∙cm-1 was

obtained by distilling deionized water Double- distilled water

(DDW) was used throughout the study

22 Conductivity measurements

The conductance measurements were taken with conductivi-

ty meter (model 4510 Jenway UK) equipped using a dip cell

(cell constant=10 cm- 1) The temperature was maintained by

circulating water through a jacket cell holding the solution un-

der study The stock solution of drug AMT (with or without

AOT) was prepared in DDW The conductivity of solvent was

measured first and then known volumes of the stock solution

of the drug were added to water (in the absence of AOT) or in

the presence of fixed concentration of the AOT solution with a

pipette and thoroughly mixed followed by measurement of

conductance Similar process was repeated after every addi-

tion The experiments were carried out under varying experi-

mental conditions Break in plot ie the point at which slope

changes is considered as the cmc of the solution All the data

were corrected with the specific conductivity of solvent The

experimental error in temperature was minimized to 020 K

3 Results and discussion31 Effect of AOT on the cmc of AMT

Mixed systems consisting of cationic- anionic surfactants1718

often outcome in strong coulombic interaction with remarkably

lower cmc in mixtures as compared to that expected for ideal

mixing In most cases the complex formed by amphiphilic

mixture is generally insoluble in water (increased Krafft point)

consequently results in limiting the studies and applications of

such systems Although for cationic-anionic combinations a

high probability of precipitation through charge neutralization

at comparable ratio is present when one component is in ex-

cess stable mixed micelles are usually formed1920 Plots of spe-

cific conductance versus [AMT] in aqueous solution at differ-

ent fixed temperatures are shown in Fig1 Specific conduc-

tance increases linearly with increasing [AMT] Above a cer-

tain concentration the slope value changes this concentration

is taken as cmc The values thus obtained with mole fractions

of the added surfactant AOT (α1) at five different temperatures

(29315 29815 30315 30815 and 31315 K) are shown in

Fig2 and also mentioned in Table 1 The cmc value of pure

AMT at 30315 K was found to be 3260 mmol∙L-1 which is

Scheme 1 Molecular structure of AMT

Scheme 2 Molecular structure of AOT

700

RUB Malik Abdul et al Temperature Dependant Mixed Micellization Behavior of a Drug-AOT MixtureNo4

inconformity with the earlier results also (ie 36 mmol∙L- 1)2122

The cmc value of the pure surfactant AOT was also observed

in good agreement with the literature value2324 The drug struc-

ture shown in Scheme 1 clearly shows that the hydrophobic

part of drug molecule is short and rigid Therefore it forms ag-

gregates at higher concentrations as compared to the AOT an-

ionic surfactant

In the present study [AOT] values used are lower than their

cmc values This means that the surfactant will either form

mixed micelles with the drug molecules2526 or remain as mono-

mers in the aqueous phase The data in Table 1 and Fig2 reveal

that with the increase in α1 values the cmc values of mixed sys-

tems decrease The cmc values of the mixed systems usually

fall in between the values of pure components Indeed it was

found so in our systems This confirms that the mixed micelles

are formed due to attractive interactions among the two compo-

nents

For ideal mixtures cmc of mixed systems can be predicted

using Clintprimes model13

1cmcid

=α1

cmc1

+α2

cmc2

(1)

In the above equation αi and cmci are the stoichiometric mole

fraction and cmc of ith component under the similar experimen-

tal circumstances This theory considers that the individual

components are non-interacting and their individual cmc values

reflect their relative tendency towards mixed micellization

Any divergence from cmcid would however account for inter-

actions among amphiphiles In the system divergence in posi-

tive and negative sides suggests antagonism and synergism re-

spectively In the present study the cmc values come out to be

lower than cmcid values which means that synergism is ob-

tained Micellization between cationic AMT and anionic surfac-

tant AOT is friendlier due to opposite charge of both the com-

ponents and as a result cmc values appear to be lower than

cmcid This indicates that AMT-AOT mixed micelles are formed

by attractive interactions

32 Effect of temperature on cmc of AMT and AOT

as well as their mixtures

Fig2 and Table 1 show the temperature dependence of cmc

of the mixed systems The cmc values of surfactants are known

to show a complex behavior with temperature cmc of nonionic

surfactants decreases with increasing temperature as the hydro-

philicity of the molecules decreases27 in contrast the effect of

temperature on the cmc of ionic surfactants is more complex It

was noticed that the cmc of ionic surfactants generally passes

through a minimum with increasing temperature28 The effect

of temperature on the cmc of amphiphiles in aqueous solution

is typically an outcome of two contrasting phenomena2930

First with the increase in temperature dehydration of the ionic

head group increases leading to an increased hydrophobicity

of the amphiphile molecule This factor favors the micelliza-

tion and hence cmc decreases In contrast the increase in tem-

perature results in the breakdown of the structured water neigh-

boring the hydrophobic portion of the amphiphile molecules

This is adverse to micellization and therefore cmc increases30

These two factors are responsible in the determination of the

cmc decrease or increase in a particular temperature range The

first factor dominates usually in low temperature range Above

a certain temperature the second factor starts dominating On

the other hand the literature also holds many example of con-

tinuous increase in cmc with temperature31 In our study too

same trend of increase in cmc is observed with temperature in

case of AOT surfactant The drug AMT while ionic in nature

acts differently from the normal surfactants This drug shows a

peaked behavior with temperature The cmc increases with the

increase in temperature from 29315 to 30315 K and then de-

creases at higher temperatures Akin activities were also report-

ed by Fontan et al32 The reason behind the decrease in cmc

suggests that at higher temperature water associated with aro-

matic rings of the drug molecules is released making the drug

more hydrophobic and this factor dominates in micelle forma-

tion Behavior of the drug in the presence of AOT remains the

same and the only change is reduction in cmc

33 Counterion association

In the ionic micelles the layer just neighboring to the sur-

Fig1 Representative plots of specific conductance versus

concentration of AMT at different temperatures

Fig2 Effect of temperature and mole fraction of AOT (α1) on

the cmc of AMT-AOT mixed system

701


face of the micelles is identified as Stern layer to which coun-

terions are bound strongly and some of them stay so even post

micelle formation An extremely charged surface is thermody-

namically unstable because of the high surface energy arising

from the electrostatic repulsions As a result the ionic micelles

associate with counterions to partially neutralize the surface

charge and minimize the electrostatic repulsions The counter-

ion association (δ) values of the pure and mixed micelles have

been evaluated from the degree of dissociation that was deter-

mined on the basis of pre- cmc slope (S1) and post-cmc slope

(S2) in the specific conductance (κ) versus drug concentration

from the expression33

δ=1-S2S1 (2)

The degree of binding (association) of the counterion (δ) in-

creases with the increase in valence and polarizability of the

ion and with the decrease in hydrated radius Therefore degree

of dissociation (g=1-δ) decreases The degree of dissociation

decreases with the increase in electrolyte concentration34 and

may decrease with micellar growth35 Also with the increase in

temperature cmc values increase and micellar growth decreas-

es Hence we can securely conclude that with the increase in

temperature increase in g is expected which is also observed

in case of ionic surfactants3637 In fact it is also obtained in our

case (Table 1) The g values of AMT and AMT-AOT mixtures

are close to each other because of very less amount of AOT

present in the systems as shown in Table 1 Note the relation-

ship values between cmc and g where it can be observed that

maximum of cmc corresponds to maximum of g The lower the

g value the easier is the micellization to occur In other words

the micellization process takes place at a lower concentration

Table 1 Physicochemical parameters for AMT-AOT mixed systems at various temperatures

TK

29315

29815

30315

30815

31315

α1

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

cmc(mmol∙L-1)

2930

2760

2595

2375

2110

1845

255

3123

2950

2800

2550

2275

1940

265

3260

3100

2930

2705

2420

2130

2800

2964

2800

2645

2450

2175

1935

300

2775

2640

2480

2275

2025

1760

315

cmcid(mmol∙L-1)

2929

2929

2928

2927

2927

3122

3122

3121

3120

3120

3259

3259

3258

3258

3257

2963

2963

2962

2962

2961

2774

2774

2773

2773

2772

g

064

064

062

061

060

058

060

065

065

064

063

062

060

062

069

068

066

064

063

061

064

071

070

069

067

065

063

066

072

071

070

068

067

065

068

∆GӨm(kJ∙mol-1)

-2486

-2521

-2579

-2627

-2687

-2771

-3408

-2497

-2523

-2559

-2610

-2668

-2762

-3403

-2453

-2492

-2548

-2614

-2671

-2755

-3391

-2486

-2528

-2567

-2632

-2713

-2794

-3373

-2533

-2569

-2610

-2680

-2741

-2831

-3333

105X1id

206

309

412

516

722

211

317

423

529

741

209

313

418

522

732

177

266

355

443

621

158

237

316

395

553

β

-841

-913

-993

-1083

-1152

-832

-891

-983

-1070

-1159

-815

-888

-966

-1055

-1123

-850

-918

-988

-1084

-1142

-843

-928

-1010

-1102

-1178

f Rub1 f M

1 f Rod1

000045000029000023

000038000026000021

000032000022000020

000029000017000017

000028000013000015

000048000026000023

000042000023000021

000034000019000019

000029000015000017

000028000011000015

000052000034000025

000042000030000024

000036000026000022

000031000020000019

000031000016000017

000040000026000021

000034000023000020

000030000020000019

000025000015000016

000026000012000015

000040000022000017

000031000019000016

000026000016000015

000022000013000013

000022000009000012

f Rub2 f M

2 f Rod2

098440997309985

095390988309875

090230955009735

082880914809106

074800955208905

098560998009964

096070991009768

090670981009688

083630967109313

074010971108937

098830999809915

096210989809730

091640956809630

084740911509220

077010927008985

098540993709978

095780983609776

091370968109573

084000924709091

076930967108942

098820997209954

095830988509738

090810973509452

083620937709236

075090986708981

g degree of dissociation β interaction parameter fRub fM fRod activity coefficients by Rubinghprimes Motomuraprimes and Rodenasprimes models

702


In our case the values of g are lower for drug+AOT mixtures

as compare to pure drug (AMT)

34 Composition and interaction between AMT and

AOT of mixed micelles

The cmc behavior of AMT-AOT mixed systems indicates mi-

cellization between the two components (drug and surfactant)

Therefore the nature of interaction between the two compo-

nents in their mixed state can be looked upon according to

Rubinghprimes regular solution theory (RST)14 RST for its simple

approach is typically used for analysis over other models The

fundamental equation is

( )X Rub1

2ln[ ](α1cmcX Rub

1 cmc1)

(1 -X Rub1 )2 ln[ ](1 -α1)cmc(1 -X Rub

1 )cmc2

= 1 (3)

where X Rub1 is the micellar mole fraction of surfactant by

Rubingh model in the mixture and cmc1 and cmc2 are the cmc

values of the pure AOT and AMT respectively Eq(3) was

solved iteratively to acquire the X1 values which were then

used to evaluate the interaction parameter β

β =ln(cmcα1cmc1 X Rub

1 )

(1 -X Rub1 )2

(4)

The results have been further evaluated by using Motomura

et al theory15 Motomura et al treatment considers mixed mi-

celles as a macroscopic bulk phase and the associated energet-

ic parameters are obtained from the excess thermodynamic

quantities similar to those associated with the adsorbed film of

surfactant The following equations are used

X M1 =

-α1 -

( )-α1

-α2

- -----cmc ( )part

- -----cmcpart

-α1

Tp

1 -δν1cν2d

ν1cν2

-α1 + ν2dν1

-α2

(5)

where v1c means that component 1 (surfactant) dissociates into

a-ions and c-ions n2d means that component 2 (drug) dissoci-

ates into b-ions and d-ions (c and d-ions are the counterparts of

the respective component) where- -----cmc = ( )ν1α1 + ν2α2 cmc (6)

-αi =

νiαi

ν1α1 + ν2α2

( i = 1 2) (7)

In the above equations X1M is the micellar mole fraction of the

surfactant-αi is the bulk mole fraction and νi is the number of

ions dissociated by the ith component d is the Kronecker delta

which is equal to 1 for identical counterions and 0 for different

counterions Hence for AMT- AOT mixed systems Eq(5) re-

duces to Eq(8)

X M1 =

-α1 -

eacuteeumlecirc

ugraveucircuacute

α1α2

2cmceacute

eumlecircecirc

ugrave

ucircuacuteuacute

part- -----cmcpart-α1 Tp

(8)

The experimental data in the present study were further ana-

lyzed using another model proposed by Rodenas et al16 which

is based on Lange and Beckprimes model38 and uses the Gibbs-

Duhem equation to relate activity coefficients of the compo-

nents in the mixed micelles From this approach the micellar

mole fractions of the components can be evaluated by Rodenas

model if the cmc values of the mixtures are known as a func-

tion of bulk stoichiometric mole fractions from the expression

X Rod1 = - (1 -α1)α1

d ln cmcdα1

+ α1 (9)

The mole fraction in an ideal state was calculated using the

equation

X id1 =

α1cmc2

α1cmc2 + α2cmc1

(10)

The micellar mole fractions of component 1 (surfactant)

evaluated by using different models ( X Rub1 X1

M and X1Rod (Fig3)

as well as X1id (Table 1)) are significantly larger than the corre-

sponding stoichiometric mole fraction (a1) All X Rub1 X1

M and

X1Rod (as well as X1

id) values for mixed systems increase with

the increase in the AOT concentration (Fig3 and Table 1) The

values of micellar mole fraction (X1) are in the same range at

lowest a1 but at higher a1 the order is X1idlt X Rub

1 ltX1RodltX1

M X1id

values show maximum at 29815 K at all mole fraction All the

Fig3 Effect of temperature and mole fraction of AOT on the

variations of X1Rub X1

M and X1Rod in AMT-AOT mixture

703


X1 values are greater than a1 This shows that the added AOT

molecules replace some of the AMT (drug) molecules from the

mixed micelles and so contribution of AOT is more in mixed

micelles than it should be in ideally mixed systems

To further investigate the results values of interaction pa-

rameter β were evaluated from Eq(4) If the values of β are

positive it means that the attractive interaction is weaker be-

tween the two different amphiphiles with each other in compar-

ison to the attractive interaction of the two individual amphiphi-

les with themselves39 In mixtures of hydrocarbon chain and flu-

orocarbon chain surfactants of the same sign only repulsive in-

teractions are found40 The larger the magnitude of β value the

greater will be the strength of the interaction between the two

molecules However it has been established41 that the attractive

interactions in mixed systems may be called as synergisticprime if

these two conditions fulfill (a) β must be negative and (b) |β|gt

|ln(cmc1cmc2)| In our case although the first condition is ful-

filled but the second one is not passed Hence it is appropriate

to use the term attractive interactionprime rather than synergismprime

in the studied cases where a negative deviation from the cmcid

is obtained The average β values βav fall between -8 to -11

indicating strong attractive interactions for the mixed systems

(Table 1) The larger the negative value of β the greater will be

the strength of the interaction between the two molecules The

β values vary throughout the concentration ranges and their

magnitude increases with the increase in concentration of AOT

Inclusion of negatively charged AOT ions between the positive-

ly charged AMT head groups reduces the repulsions among the

AMT molecules and AMT- AOT mixed micelles would occur

more attractive interactions

The activity coefficients ( f Rub1 and f Rub

2 ) of the two comp-

onents within the micelles were evaluated by knowing the val-

ues of mole fraction of AOT in the micellar phase and molecu-

lar interaction parameters for the mixed micelles using equa-

tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)

The activity coefficients (f1 and f2) were also evaluated from

Motomura et al and Rodenas et al models

f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)

For AMT-AOT mixed systems activity coefficients f1 and

f2 calculated by Rubingh Motomura et al and Rodenas et

al models are less than unity at all mole fractions and tempera-

tures which indicate attractive nonideal behavior of the mixed

systems (Table 1)

We have also evaluated the excess free energy of micelliza-

tion (Gex) through the following equations for the achieving ad-

ditional information about the mixed systems4243

ΔGRubex = RT[X1 ln f Rub

1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod

1 ln f Rod1 +(1 -X Rod

1 )ln f Rod2 ] (17)

The excess free energy is found to be zero for an ideal

system The DGex values estimated by considering Rubinghprimes

Motomura et al and Rodena et al approaches are shown in

Fig4 One can see that the trend of DGex with mixture composi-

tion is the same sets of values for the Motomura et al and

Rodena et al approaches but the values obtained from Rub-

ingh model are somewhat lower These values come out to be

negative and their magnitude increases with the increase in

AOT concentrations (Fig4) This proves that the mixed mi-

celles formed are more stable than the micelles of individual

components and their stability increases with the increase in

concentration of AOT With temperature the DGex values show

a minimum at 30315 K for all models but there is no signifi-

cant effect of temperatures on the DGex values (Fig4)

35 Thermodynamics of micellization

According to the pseudo-phase separation model44 the stan-

dard Gibbs energy of micellization DGӨm for ionic uni-univa-

lent amphiphiles can be calculated by taking into account the

degree of dissociation (g) of the counterion to the micelle

DGӨm=(2-g)RTlnXcmc (18)

where Xcmc R and T are the cmc expressed in mole fraction

units gas constant and absolute temperature respectively

The standard enthalpy (ΔHmӨ) and entropy (ΔSm

Ө) can then be

calculated using equations

DHӨm = - (2 -g)RT 2eacute

eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)

The obtained ΔGmӨ values are all negative and vary slightly

with the increase in temperature (Table 1) The ΔGmӨ values for

pure components agree well with literature data23244546 As usu-

al the micellization process is thus governed primarily by the

entropy gain associated with the propensity of the hydrophobic

Fig4 Variations of ΔGRex ΔGM

ex and ΔG Re dex versus mole fraction

of AOT (α1) in PMZ-hydrotrope mixtures at different temperaturesThe models used were Rubingh (filled symbols) Motomura et al

(open symbols) Rodenas et al (half-filled symbols)

704


group of amphiphile to transfer from the aqueous environment

to the interior of micelle The low magnitude of ΔGmӨ values for

pure AMT and AMT-AOT mixed systems as compared to pure

AOT indicates low hydrophobicity of the AMT (drug) which is

also clear from respective cmc value As the AOT surfactant

contains long hydrophobic part the process of micelle forma-

tion is spontaneous and more favorable which is evident from

low cmc and more negative ΔGmӨ values For AMT-AOT mixed

systems ΔGmӨ becomes increasingly more negative indicating

easiness of micelle formation in mixed systems

The ΔHmӨ value for micellization of pure AOT is negative

and the magnitude increases with increasing the temperature in

almost all cases (Fig5) The ΔHmӨ values of pure drug change

from negative to positive with increasing the temperature from

29315 to 30815 K (the process is exothermic at 29315 K and

it becomes endothermic as the temperature increases to 30815

K) The negative values of ΔHmӨ recommend the significance of

the London-dispersion interactions as an attractive force for mi-

cellization while positive values indicate the breaking of struc-

tured water around the hydrophobic portions of the molecule4748

Similar development was found for AMT-AOT mixed systems

with the difference in magnitude of ΔHmӨ (Fig5) This may be

because of the difference in the hydration between the saturat-

ed and aromatic hydrocarbon portions of the drug AMT

(Scheme 1) At higher temperatures release of water associat-

ed with the aromatic ring of AMT takes place This enhances

the hydrophobicity of drug molecules building the process

endothermic

The ΔSmӨ value for micellization of pure AOT is positive and

decreases with increasing the temperature (Fig6) The entropy

of micellization (ΔSmӨ) is positive at all temperatures signifying

that the micellization process is entropy dominated in these sys-

tems chiefly when entropy change is high Although entropy

of micellization (ΔSmӨ) is positive at all temperatures for pure

drug (AMT) but the trend is different from pure AOT ie the

values are small at 29315- 30315 K and increases sharply

with the increase in temperature at 30815 K and above Ob-

servably this is caused by the particular structure of AMT

which is the major component of the mixed micelles Apparent-

ly the key lies in the difference in the hydration between the

saturated and aromatic hydrocarbon portions of the drug mole-

cule The high increase in entropy indicates a strong discharge

of water which possibly is the water associated with the aro-

matic ring of drug This in turn must enhance the hydropho-

bicity of drug molecules causing a decrease of cmc (Table 1

and Fig2) Similar behavior is also found in case of AMT-

AOT mixtures As is clear from Fig6 the magnitude of ΔSmӨ is

higher in the presence of AOT comparative to their absence

which means that the presence of surfactant (AOT) increases

the randomness in the system

4 ConclusionsThis work has presented the experimental investigations of

the effect of AOT surfactant on the micellization behavior of

an amphiphilic antidepressant drug AMT at different tempera-

tures and compositions Surfactants are usually used as drug

carriers in pharmaceuticals but the occurrence of surfactants

may alter the micellization tendency of a drug as surfactants

form mixed micelles with the drug this may affect the activity

of the drug Hence it is important to have knowledge of the ef-

fect of surfactants on micelle formation of drugs and the relat-

ed energetics Keeping in view the above we have performed

conductometric technique for cmc determination of pure AMT

and AMT-AOT mixed systems The following conclusions can

be drawn from the study

(1) AMT forms mixed micelles with AOT through attractive

interactions as indicated by the cmc and cmcid values

(2) X1 values calculated by different proposed models show

higher contribution of AOT in the mixed micelles These val-

ues are higher than X1id

(3) β values calculated using Rubingh approach also indicate

attractive interactions among micelles

(4) For AMT-AOT mixed systems ΔGmӨ becomes increasing-

ly more negative indicating easiness of micelle formation in

mixed systems

(5) The ΔHmӨ values of AMT- AOT mixed systems change




enthalpy of micellization (∆HӨm) of AMT-AOT mixed system


entropy of micellization (∆SӨm) of AMT-AOT mixed system

705



K)

(6) The ΔSmӨ values at lower temperatures (29315-30315 K)

are small whereas at higher temperatures (30815 K and above)

the magnitude increases the sign remains positive for all sys-

tems The magnitude is higher in the presence of AOT relative

to that in their absence Presence of AOT increases the random-

ness in the systems

References

(1) Rodrigues M P Prieto G Rega C Varela L M Sarmiento

F Mosquera V Langmuir 1998 14 4422 doi 101021

la980296a

(2) Attwood D Blundwell R Mosquea V Garcia M J Colloid

Interface Sci 1993 161 19 doi 101006jcis19931434

(3) Attwood D Tolley J A J Pharm Pharmacol 1980 32

761 doi 101111jphp198032issue-1

(4) Taboada P Attwood D Ruso J M Garcia M Sarmiento

F Mosquea V J Colloid Interface Sci 1999 216 270 doi

101006jcis19996300

(5) Allen T M Hansen C B Menenez D E L Adv Drug Deliv

Rev 1995 16 267 doi 1010160169-409X(95)00029-7

(6) Canto G S Dalmora S L Oliveira A G Drug Dev Ind

Pharm 1999 25 1235 doi 101081DDC-100102293

(7) De S Aswal V K Goyal P S Bhattacharya S J Phys

Chem 1996 100 11664 doi 101021jp9535598

(8) Lipinski C A Lombardo F Dominy B W Feeney P J Adv

Drug Deliv Rev 2001 46 3 doi 101016S0169-409X(00)

00129-0

(9) Fernandez A M Van Derpoorten K Dasnois L Lebtahi K

Dubois V Lobl T J Gangwar S Oliyai C Lewis E R

Shochat D Trouet A J Med Chem 2001 44 3750 doi

101021jm0108754

(10) Halliwell W H Toxicologic Pathalogy 1997 25 53 doi

101177019262339702500111

(11) Rangel-Yagui C O Pessoa A Jr Tavares L C J Pharm

Pharmaceut Sci 2005 8 147

(12) Torchilin V P J Control Rel 2001 73 137 doi 101016

S0168-3659(01)00299-1

(13) Clint J H J Chem Soc Faraday Trans 1 1975 71 1327 doi

101039f19757101327

(14) Rubingh D N Solution Chemistry of Surfactants Mittal K L

Ed Plenum Press New York 1979

(15) Motomura K Yamanaka M Aratono M Colloid Polym Sci

1984 262 948 doi 101007BF01490027

(16) Rodenas V Valiente M Villafruela M S J Phys Chem B

1999 103 4549 doi 101021jp981871m

(17) Barker C A Saul D Tiddy G J T Wheeler B A Willis

E J Chem Soc Faraday Trans 1 1974 70 154 doi 101039

f19747000154

(18) Vethamuthu M S Almgren M Karlsson G Bahadur P

Langmuir 1996 12 2173 doi 101021la950964h

(19) Mandal A B Moulik S P Solution Behavior of Surfactants

Mittal K L Fendler E J Eds Plenum Press New York

1982

(20) Elworthy P H Florence A T Macfarlane G B

Solubilization by Surface-Active Agents and Its Application in

Chemistry and Biological Sciences Chapman and Hall Suffolk

1968

(21) Attwood D Florence A T Surfactant Systems Their

Chemistry Pharmacy and Biology Chapman and Hall New

York 1983

(22) Kabir-ud-Din Rub M A Naqvi A Z J Phys Chem B 2010

114 6354 doi 101021jp100123r

(23) Chakraborty A Chakraborty S Saha S K J Disp Sci

Technol 2007 28 984 doi 10108001932690701463175

(24) Chatterjee A Moulik S P Sanyal S K Mishra B K Puri

P M J Phys Chem B 2001 105 12823 doi 101021

jp0123029

(25) Kabir-ud-Din Rub M A Naqvi A Z J Colloid Interface Sci

2011 354 700 doi 101016jjcis201011005

(26) Rodriguez A Junquera E del Burgo P Aicart E J Colloid

Interface Sci 2004 269 476 doi 101016jjcis200309028

(27) Meguro K Ueno M Esumi K Nonionic Surfactants

Physical Chemistry Schick M J Ed Dekker New York 1987

(28) Mosquera V del Rio J M Attwood D Garcia M Jones

M N Prieto G Suarez M J Sarmiento F J Colloid


(29) Chen L Shi-Yow L Huang C C Chen E M Colloids Surf

A 1998 135 175 doi 101016S0927-7757(97)00238-0

(30) Hunter R J Foundations of Colloid Science Vol 1 Oxford

University Press New York 1989

(31) Das C Das B J Chem Eng Data 2009 54 559 doi

101021je8005024

(32) Fontan J L L Costa J Ruso J M Prieto G Sarmiento F

J Chem Eng Data 2004 49 1008 doi 101021je049954l

(33) Evans H C J Chem Soc 1956 117 579

(34) Asakawa T Kitano H Ohta A Miyagishi S J Colloid


(35) Iijima H Kato T Soderman A Langmuir 2000 16 318 doi

101021la9902688

(36) Zana R J Colloid Interface Sci 1980 78 330 doi 101016

0021-9797(80)90571-8

(37) Gorski N Kalus J Langmuir 2001 17 4211 doi 101021

la0017882

(38) Lange H Beck K H Kolloid Z Z Polym 1973 251

424 doi 101007BF01498689

(39) Rosen M J Surfactants and Interfacial Phenomena 3rd ed

John Wiley amp Sons New York 2004

(40) Blanco E Messina P Ruso J M Prieto G Sarmiento F

J Phys Chem B 2006 110 11369 doi 101021jp060795h

(41) Hua X Y Rosen M J J Colloid Interface Sci 1982 90

706


212 doi 1010160021-9797(82)90414-3

(42) Maeda H J Phys Chem B 2005 109 15933 doi 101021

jp052082p

(43) Hall D G J Chem Soc Faraday Trans 1991 87 3529 doi

101039ft9918703529

(44) Clint J H Surfactant Aggregation BlackieChapman and Hall

New York 1992

(45) Rub M A Asiri A M Azum N Khan A Khan A A P

Khan S B Rahman M M Kabir-ud-Din J Ind Eng Chem

2013 19 1774 doi 101016jjiec201302019

(46) Rub M A Asiri A M Azum N Kabir-ud-Din J Ind Eng

Chem doi 101016jjiec201309027

(47) Nusselder J J H Engberts J B F N J Colloid Interface Sci

1992 148 353 doi 1010160021-9797(92)90174-K

(48) Kresheck G C Water A Comprehensive Treatise Franks F


105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906105090610509061050906第十二届全国量子化学会议第十二届全国量子化学会议(太原太原2014)

第一轮通知

由中国化学会主办山西师范大学化学与材料科学学院承办的第十二届全国量子化学会议将于2014年6月12－15日在太原举行本次

会议内容涵盖理论与计算化学的各个方面将有众多的海内外学者和研究生参加会议将邀请海内外著名专家作大会报告和邀请报告并安

排张贴报告展讲受国家自然科学基金委员会化学部的委托会议期间还将邀请部分专家学者参加ldquo理论与计算化学发展战略研讨会rdquo会议

组织委员会热诚欢迎从事理论和计算化学研究的同行踊跃参加这次学术盛会

一一会议征文范围会议征文范围

1 量子化学理论和计算方法2 分子团簇固体等的电子结构和谱学计算3 催化反应机理分子激发态和光化学反应机理的理论研究

4 各种材料的结构与性能关系及理论设计5 反应动力学理论和应用6 量子化学和分子模拟在生物环境和能源等领域的应用7 其它理论

与计算化学研究

二二征文要求征文要求

1 符合征文范围未公开发表的论文均可应征2 页面设置为A4论文标题要求尽量简短用3号(16 pt)黑体字居中3 作者姓名用4号

(1375 pt)楷体作者单位用5号(105 pt)宋体正文用小4号(12 pt)宋体行距为15倍4 插图宽度一般为60 mm左右附表为三线表图表

中的字符使用6号(8 pt)字5 参考文献请按《化学学报》格式著录ldquo参考文献rdquo四个字用小4号(9 pt)黑体文献用5号字6 可以用英文稿

三三张贴报告格式张贴报告格式

会议将为每位注册代表提供一个张贴报告展位尺寸120 cm(高)times90 cm(宽)

四四顾问委员会顾问委员会

主席徐光宪

委员张乾二张存浩江元生黎乐民刘若庄朱清时陈凯先鄢国森戴树珊何福成赵成大

五五大会学术委员会大会学术委员会

主席黎乐民吴云东副主席方维海帅志刚

委员(按姓氏字母顺序排列)

曹泽星陈冠华程寒松范康年高加力高毅勤韩克利焦海军黎书华李隽李前树李微雪李象远李泽生

梁万珍刘成卜刘文剑罗毅邵久书苏忠民文振翼吴玮武海顺谢代前徐昕严以京杨金龙杨伟涛

杨忠志曾晓成张东辉张红星张增辉

六六大会组织委员会大会组织委员会

主任武海顺副主任李思殿


焦海军贾建峰宁士荣王宝俊王越奎许小红薛珠峰张献明张支平

七七会议联络组会议联络组

贾建峰(山西师范大学) 吕瑾(山西师范大学)

秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)

联系地址山西临汾山西师范大学化学与材料科学学院 (041004) 贾建峰

会议专用E-mailcqcsxnueducn会议网站httpncqc2014sxnueducn

八八会议重要日程与事项会议重要日程与事项

1 会议时间2014年6月12日至6月15日(12日报到)

2 会议地点太原

3 报名和会议摘要截至日期2014年5月10日(可网络注册预报名并提交摘要摘要要求详见会议主页)

4 其他注意事项

(1) 会议注册网址httpncqc2014sxnueducn会议代表可在网上进行注册论文摘要的提交也可在网上进行对不便使用网络登录者

可使用注册表填写后E-mail邮寄或传真到会议筹备组

(2) 第二轮通知将于2014年3月发出第三轮通知将于2014年5月发出敬请关注

(3) 本通知同时在会议网站上发布自即日起到会议结束会议有关情况将随时在会议网站发布

707


use in association with different drug carrier systems which

may alter their chemical activity and pharmacological behav-

ior67 The development of such a drug carrier is still facing a

challenging problem because of its low water-solubility gener-

ally resulting in poor absorption and bioavailability which

leads to drug aggregation-related complications such as embo-

lism89 In addition such antidepressant drugs have been found

to interact with phospholipids of bio-membrane resulting in

their accumulation a condition referred to as phospholipido-

sis10 In view of this it necessitates the need of formulation of

AMT drug which might reduce its tendency to bind with phos-

pholipids without affecting its activity

In this regard surfactant micelles show some superior advan-

tages over other alternatives like soluble polymers and lipo-

somes11 Micellar systems can be used to solubilize poorly solu-

ble drugs and hence increase their bioavailability They can

stay in the body (blood) for a long time to provide gradual ac-

cumulation in the required area and also their sizes allow them

to accumulate in areas with leaky vasculature12

Therefore in search of enhanced utility and to provide fur-

ther input we have systematically studied the physicochemical

properties of AMT-AOT (sodium bis(2-ethylhexyl)-sulfosucci-

nate) mixed systems conductometrically in a very low concen-

tration range of AOT

AOT is a well-known and versatile anionic surfactant con-

taining two hydrophobic tails This typical molecular structure

of AOT may be responsible for its ability to form microemul-

sion and show rich phase behavior (Scheme 2) A number of

models eg Clintprimes13 Rubinghprimes14 Motomuraprimes15 and Rodenasprimes16

were used to obtain different parameters related to mixed mi-

celles The effect of temperature on micelle formation was also

studied which gives information about relative characterization

of amphiphile solutions This information is obtained from the

thermodynamic parameters of micelle formation ie standard

Gibbprimes energy (ΔGӨm) enthalpy (ΔHӨ

m) and entropy of micelliza-

tion (ΔSӨm) that quantify the relative importance of electrostatic

and hydrophobic interaction

2 Experimental21 Materials

Reagents used in this study are given here along with their

make and purity AMT (ge98) supplied by Sigma USA was

used as received Anionics surfactant AOT is Aldrich USA

product with ge97 purity was used without further purifica-

tion Water with a conductivity of 1times10-6-2times10-6 Ω-1∙cm-1 was

obtained by distilling deionized water Double- distilled water

(DDW) was used throughout the study

22 Conductivity measurements

The conductance measurements were taken with conductivi-

ty meter (model 4510 Jenway UK) equipped using a dip cell

(cell constant=10 cm- 1) The temperature was maintained by

circulating water through a jacket cell holding the solution un-

der study The stock solution of drug AMT (with or without

AOT) was prepared in DDW The conductivity of solvent was

measured first and then known volumes of the stock solution

of the drug were added to water (in the absence of AOT) or in

the presence of fixed concentration of the AOT solution with a

pipette and thoroughly mixed followed by measurement of

conductance Similar process was repeated after every addi-

tion The experiments were carried out under varying experi-

mental conditions Break in plot ie the point at which slope

changes is considered as the cmc of the solution All the data

were corrected with the specific conductivity of solvent The

experimental error in temperature was minimized to 020 K

3 Results and discussion31 Effect of AOT on the cmc of AMT

Mixed systems consisting of cationic- anionic surfactants1718

often outcome in strong coulombic interaction with remarkably

lower cmc in mixtures as compared to that expected for ideal

mixing In most cases the complex formed by amphiphilic

mixture is generally insoluble in water (increased Krafft point)

consequently results in limiting the studies and applications of

such systems Although for cationic-anionic combinations a

high probability of precipitation through charge neutralization

at comparable ratio is present when one component is in ex-

cess stable mixed micelles are usually formed1920 Plots of spe-

cific conductance versus [AMT] in aqueous solution at differ-

ent fixed temperatures are shown in Fig1 Specific conduc-

tance increases linearly with increasing [AMT] Above a cer-

tain concentration the slope value changes this concentration

is taken as cmc The values thus obtained with mole fractions

of the added surfactant AOT (α1) at five different temperatures

(29315 29815 30315 30815 and 31315 K) are shown in

Fig2 and also mentioned in Table 1 The cmc value of pure

AMT at 30315 K was found to be 3260 mmol∙L-1 which is

Scheme 1 Molecular structure of AMT

Scheme 2 Molecular structure of AOT

700








ionic surfactant










nents



1cmcid

=α1

cmc1

+α2

cmc2

(1)



























































701














δ=1-S2S1 (2)



















TK

29315

29815

30315

30815

31315

α1

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

cmc(mmol∙L-1)

2930

2760

2595

2375

2110

1845

255

3123

2950

2800

2550

2275

1940

265

3260

3100

2930

2705

2420

2130

2800

2964

2800

2645

2450

2175

1935

300

2775

2640

2480

2275

2025

1760

315

cmcid(mmol∙L-1)

2929

2929

2928

2927

2927

3122

3122

3121

3120

3120

3259

3259

3258

3258

3257

2963

2963

2962

2962

2961

2774

2774

2773

2773

2772

g

064

064

062

061

060

058

060

065

065

064

063

062

060

062

069

068

066

064

063

061

064

071

070

069

067

065

063

066

072

071

070

068

067

065

068

∆GӨm(kJ∙mol-1)

-2486

-2521

-2579

-2627

-2687

-2771

-3408

-2497

-2523

-2559

-2610

-2668

-2762

-3403

-2453

-2492

-2548

-2614

-2671

-2755

-3391

-2486

-2528

-2567

-2632

-2713

-2794

-3373

-2533

-2569

-2610

-2680

-2741

-2831

-3333

105X1id

206

309

412

516

722

211

317

423

529

741

209

313

418

522

732

177

266

355

443

621

158

237

316

395

553

β

-841

-913

-993

-1083

-1152

-832

-891

-983

-1070

-1159

-815

-888

-966

-1055

-1123

-850

-918

-988

-1084

-1142

-843

-928

-1010

-1102

-1178

f Rub1 f M

1 f Rod1

000045000029000023

000038000026000021

000032000022000020

000029000017000017

000028000013000015

000048000026000023

000042000023000021

000034000019000019

000029000015000017

000028000011000015

000052000034000025

000042000030000024

000036000026000022

000031000020000019

000031000016000017

000040000026000021

000034000023000020

000030000020000019

000025000015000016

000026000012000015

000040000022000017

000031000019000016

000026000016000015

000022000013000013

000022000009000012

f Rub2 f M

2 f Rod2

098440997309985

095390988309875

090230955009735

082880914809106

074800955208905

098560998009964

096070991009768

090670981009688

083630967109313

074010971108937

098830999809915

096210989809730

091640956809630

084740911509220

077010927008985

098540993709978

095780983609776

091370968109573

084000924709091

076930967108942

098820997209954

095830988509738

090810973509452

083620937709236

075090986708981


702













( )X Rub1

2ln[ ](α1cmcX Rub

1 cmc1)

(1 -X Rub1 )2 ln[ ](1 -α1)cmc(1 -X Rub

1 )cmc2

= 1 (3)







1 )

(1 -X Rub1 )2

(4)







X M1 =

-α1 -

( )-α1

-α2

- -----cmc ( )part

- -----cmcpart

-α1

Tp

1 -δν1cν2d

ν1cν2

-α1 + ν2dν1

-α2

(5)





-αi =

νiαi

ν1α1 + ν2α2

( i = 1 2) (7)






duces to Eq(8)

X M1 =

-α1 -

eacuteeumlecirc

ugraveucircuacute

α1α2

2cmceacute

eumlecircecirc

ugrave

ucircuacuteuacute


(8)









X Rod1 = - (1 -α1)α1

d ln cmcdα1

+ α1 (9)


equation

X id1 =

α1cmc2

α1cmc2 + α2cmc1

(10)



M and X1Rod (Fig3)



M and






1 ltX1RodltX1

M X1id





703





































tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)



f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)





systems (Table 1)





1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod


1 )ln f Rod2 ] (17)
























Ө) can then be



eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)










704





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707








ionic surfactant










nents



1cmcid

=α1

cmc1

+α2

cmc2

(1)



























































701














δ=1-S2S1 (2)



















TK

29315

29815

30315

30815

31315

α1

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

cmc(mmol∙L-1)

2930

2760

2595

2375

2110

1845

255

3123

2950

2800

2550

2275

1940

265

3260

3100

2930

2705

2420

2130

2800

2964

2800

2645

2450

2175

1935

300

2775

2640

2480

2275

2025

1760

315

cmcid(mmol∙L-1)

2929

2929

2928

2927

2927

3122

3122

3121

3120

3120

3259

3259

3258

3258

3257

2963

2963

2962

2962

2961

2774

2774

2773

2773

2772

g

064

064

062

061

060

058

060

065

065

064

063

062

060

062

069

068

066

064

063

061

064

071

070

069

067

065

063

066

072

071

070

068

067

065

068

∆GӨm(kJ∙mol-1)

-2486

-2521

-2579

-2627

-2687

-2771

-3408

-2497

-2523

-2559

-2610

-2668

-2762

-3403

-2453

-2492

-2548

-2614

-2671

-2755

-3391

-2486

-2528

-2567

-2632

-2713

-2794

-3373

-2533

-2569

-2610

-2680

-2741

-2831

-3333

105X1id

206

309

412

516

722

211

317

423

529

741

209

313

418

522

732

177

266

355

443

621

158

237

316

395

553

β

-841

-913

-993

-1083

-1152

-832

-891

-983

-1070

-1159

-815

-888

-966

-1055

-1123

-850

-918

-988

-1084

-1142

-843

-928

-1010

-1102

-1178

f Rub1 f M

1 f Rod1

000045000029000023

000038000026000021

000032000022000020

000029000017000017

000028000013000015

000048000026000023

000042000023000021

000034000019000019

000029000015000017

000028000011000015

000052000034000025

000042000030000024

000036000026000022

000031000020000019

000031000016000017

000040000026000021

000034000023000020

000030000020000019

000025000015000016

000026000012000015

000040000022000017

000031000019000016

000026000016000015

000022000013000013

000022000009000012

f Rub2 f M

2 f Rod2

098440997309985

095390988309875

090230955009735

082880914809106

074800955208905

098560998009964

096070991009768

090670981009688

083630967109313

074010971108937

098830999809915

096210989809730

091640956809630

084740911509220

077010927008985

098540993709978

095780983609776

091370968109573

084000924709091

076930967108942

098820997209954

095830988509738

090810973509452

083620937709236

075090986708981


702













( )X Rub1

2ln[ ](α1cmcX Rub

1 cmc1)

(1 -X Rub1 )2 ln[ ](1 -α1)cmc(1 -X Rub

1 )cmc2

= 1 (3)







1 )

(1 -X Rub1 )2

(4)







X M1 =

-α1 -

( )-α1

-α2

- -----cmc ( )part

- -----cmcpart

-α1

Tp

1 -δν1cν2d

ν1cν2

-α1 + ν2dν1

-α2

(5)





-αi =

νiαi

ν1α1 + ν2α2

( i = 1 2) (7)






duces to Eq(8)

X M1 =

-α1 -

eacuteeumlecirc

ugraveucircuacute

α1α2

2cmceacute

eumlecircecirc

ugrave

ucircuacuteuacute


(8)









X Rod1 = - (1 -α1)α1

d ln cmcdα1

+ α1 (9)


equation

X id1 =

α1cmc2

α1cmc2 + α2cmc1

(10)



M and X1Rod (Fig3)



M and






1 ltX1RodltX1

M X1id





703





































tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)



f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)





systems (Table 1)





1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod


1 )ln f Rod2 ] (17)
























Ө) can then be



eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)










704





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707














δ=1-S2S1 (2)



















TK

29315

29815

30315

30815

31315

α1

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

0

179times10-6

269times10-6

359times10-6

449times10-6

628times10-6

10

cmc(mmol∙L-1)

2930

2760

2595

2375

2110

1845

255

3123

2950

2800

2550

2275

1940

265

3260

3100

2930

2705

2420

2130

2800

2964

2800

2645

2450

2175

1935

300

2775

2640

2480

2275

2025

1760

315

cmcid(mmol∙L-1)

2929

2929

2928

2927

2927

3122

3122

3121

3120

3120

3259

3259

3258

3258

3257

2963

2963

2962

2962

2961

2774

2774

2773

2773

2772

g

064

064

062

061

060

058

060

065

065

064

063

062

060

062

069

068

066

064

063

061

064

071

070

069

067

065

063

066

072

071

070

068

067

065

068

∆GӨm(kJ∙mol-1)

-2486

-2521

-2579

-2627

-2687

-2771

-3408

-2497

-2523

-2559

-2610

-2668

-2762

-3403

-2453

-2492

-2548

-2614

-2671

-2755

-3391

-2486

-2528

-2567

-2632

-2713

-2794

-3373

-2533

-2569

-2610

-2680

-2741

-2831

-3333

105X1id

206

309

412

516

722

211

317

423

529

741

209

313

418

522

732

177

266

355

443

621

158

237

316

395

553

β

-841

-913

-993

-1083

-1152

-832

-891

-983

-1070

-1159

-815

-888

-966

-1055

-1123

-850

-918

-988

-1084

-1142

-843

-928

-1010

-1102

-1178

f Rub1 f M

1 f Rod1

000045000029000023

000038000026000021

000032000022000020

000029000017000017

000028000013000015

000048000026000023

000042000023000021

000034000019000019

000029000015000017

000028000011000015

000052000034000025

000042000030000024

000036000026000022

000031000020000019

000031000016000017

000040000026000021

000034000023000020

000030000020000019

000025000015000016

000026000012000015

000040000022000017

000031000019000016

000026000016000015

000022000013000013

000022000009000012

f Rub2 f M

2 f Rod2

098440997309985

095390988309875

090230955009735

082880914809106

074800955208905

098560998009964

096070991009768

090670981009688

083630967109313

074010971108937

098830999809915

096210989809730

091640956809630

084740911509220

077010927008985

098540993709978

095780983609776

091370968109573

084000924709091

076930967108942

098820997209954

095830988509738

090810973509452

083620937709236

075090986708981


702













( )X Rub1

2ln[ ](α1cmcX Rub

1 cmc1)

(1 -X Rub1 )2 ln[ ](1 -α1)cmc(1 -X Rub

1 )cmc2

= 1 (3)







1 )

(1 -X Rub1 )2

(4)







X M1 =

-α1 -

( )-α1

-α2

- -----cmc ( )part

- -----cmcpart

-α1

Tp

1 -δν1cν2d

ν1cν2

-α1 + ν2dν1

-α2

(5)





-αi =

νiαi

ν1α1 + ν2α2

( i = 1 2) (7)






duces to Eq(8)

X M1 =

-α1 -

eacuteeumlecirc

ugraveucircuacute

α1α2

2cmceacute

eumlecircecirc

ugrave

ucircuacuteuacute


(8)









X Rod1 = - (1 -α1)α1

d ln cmcdα1

+ α1 (9)


equation

X id1 =

α1cmc2

α1cmc2 + α2cmc1

(10)



M and X1Rod (Fig3)



M and






1 ltX1RodltX1

M X1id





703





































tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)



f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)





systems (Table 1)





1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod


1 )ln f Rod2 ] (17)
























Ө) can then be



eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)










704





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707













( )X Rub1

2ln[ ](α1cmcX Rub

1 cmc1)

(1 -X Rub1 )2 ln[ ](1 -α1)cmc(1 -X Rub

1 )cmc2

= 1 (3)







1 )

(1 -X Rub1 )2

(4)







X M1 =

-α1 -

( )-α1

-α2

- -----cmc ( )part

- -----cmcpart

-α1

Tp

1 -δν1cν2d

ν1cν2

-α1 + ν2dν1

-α2

(5)





-αi =

νiαi

ν1α1 + ν2α2

( i = 1 2) (7)






duces to Eq(8)

X M1 =

-α1 -

eacuteeumlecirc

ugraveucircuacute

α1α2

2cmceacute

eumlecircecirc

ugrave

ucircuacuteuacute


(8)









X Rod1 = - (1 -α1)α1

d ln cmcdα1

+ α1 (9)


equation

X id1 =

α1cmc2

α1cmc2 + α2cmc1

(10)



M and X1Rod (Fig3)



M and






1 ltX1RodltX1

M X1id





703





































tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)



f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)





systems (Table 1)





1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod


1 )ln f Rod2 ] (17)
























Ө) can then be



eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)










704





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707





































tions

f Rub1 = exp β(1 -X1 )2 (11)

f Rub2 = exp β(X1 )2 (12)



f1 =α1cmc

X1 cmc1

(13)

f2 =(1 -α1)cmc

(1 -X1 )cmc2

(14)





systems (Table 1)





1 +(1 -X1 )ln f Rub2 ] (15)

ΔGMex = RT[X M

1 ln f M1 +(1 -X M

1 )ln f M2 ] (16)

ΔGRodex = RT[X Rod


1 )ln f Rod2 ] (17)
























Ө) can then be



eumlecirc

ugraveucircuacute

d ln Xcmc

dT(19)

DSӨm =

ΔH Өm -ΔGӨ

m

T(20)










704





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707





























endothermic













































mixed systems








705



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707



K)






ness in the systems

References



la980296a




761 doi 101111jphp198032issue-1



101006jcis19996300


Rev 1995 16 267 doi 1010160169-409X(95)00029-7


Pharm 1999 25 1235 doi 101081DDC-100102293


Chem 1996 100 11664 doi 101021jp9535598



00129-0




101021jm0108754


101177019262339702500111




S0168-3659(01)00299-1


101039f19757101327




1984 262 948 doi 101007BF01490027


1999 103 4549 doi 101021jp981871m



f19747000154


Langmuir 1996 12 2173 doi 101021la950964h



1982




1968



York 1983


114 6354 doi 101021jp100123r


Technol 2007 28 984 doi 10108001932690701463175



jp0123029


2011 354 700 doi 101016jjcis201011005









A 1998 135 175 doi 101016S0927-7757(97)00238-0




101021je8005024







101021la9902688


0021-9797(80)90571-8


la0017882


424 doi 101007BF01498689






706


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707


212 doi 1010160021-9797(82)90414-3


jp052082p


101039ft9918703529


New York 1992



2013 19 1774 doi 101016jjiec201302019




1992 148 353 doi 1010160021-9797(92)90174-K




第一轮通知
















主席徐光宪














秘书郭彩红(0357-2051375) 张婷婷(0357-2051077)












707

Documents

Temperature Dependant Mixed Micellization Behavior of a