Superhydrophobic Surface and Application

Jian Xu, Ning ZhaoNational Laboratory of Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences

Superhydrophoic and Superhydrophoic and

suphydrophilic surfacesuphydrophilic surface

－－ Its Its architecturearchitecture and applications and applications

Outline

1.Background

2.Our Work

Transparent superhydrophilic and Ultra-hydrophobic

coatings with anti-fogging & anti-reflective properties

3. Application:

Performance of AR coating on solar cell

4. Conclusion

Background

Surface wettabilitySurface wettability

Cell adhesion and growth

Catalyzing

Waterproof

Oil extraction

Lubrication

Self-cleaning

173.0o±2.5

o

Surfaces with a special wettabilitySurfaces with a special wettability

Superhydrophobic surface with lotus effect Superhydrophilic surface with anti-fogging property

Gradient wettability

Response to Electrical Potential

Surface with a reversible wettability responsive to external stimuli

Macromol. Rapid Commun. 2004, 25, 1606 Nano Letters 2006, 6, 2305

Langmuir 2004, 20, 5952 Science 2003, 299, 371

Previous work: Previous work: superhydrophobic polymeric coatingssuperhydrophobic polymeric coatings

PMMA PS

PS-b-PDMSPP-b-PMMA

PC

Macromolecules,Macromolecules, 2005, 2005, 38, 38, 8996. 8996.

Adv. Mater.Adv. Mater., 2004, 16, 302; 16, 1830., 2004, 16, 302; 16, 1830.

Macromol. Rapid Commun., 2005, 26, 1075

ChemPhysChem, 2007, 8,1108; 7, 8247, 824

Experimental route design

After step 1 After step 2

Nanoparticle preparation

With a diameter of 30nm

LBLfilm UV+ O3

1 2

Superhydrophilic film with

antifogging property

The profile image of water droplet on the surface

Previous work: Previous work: superhydrophilic inorganic-organic hybrid coatingssuperhydrophilic inorganic-organic hybrid coatings

The profile image of water droplet on the surface

Characterization of superhydrophilic surface Characterization of superhydrophilic surface

Outline

1.Background

2.Our Work2.Our Work

Transparent superhydrophilic and Ultra-hydrophobic

coatings with anti-fogging & anti-reflective properties

3. Application:

Performance of AR coating on solar cell

4. Conclusion

Surface morphology of the transparent filmSurface morphology of the transparent film

SEM image AFM image

Inorganic and organic hybrids film with nanostructure

Hydrophobic modification with different silanes

146.5±2.3 147.2±1.3 149.0±1.6 153.6±2.6

CTMS ODMCS OTDDMCS TDF-DMCS

Superhydrophobic & transparent coatingSuperhydrophobic & transparent coating

CA : 149.0±1.6º

Superhydrophilic surface Superhydrophilic surface Antifogging property

Glass slide in a humid air after

cooled in icebox for 20 min. Glass slide holding on a

beaker with 80 hot water ℃

coated uncoated

300 400 500 600 700 80080

85

90

95

100

Tra

nsm

itta

nce (

%)

Wavelength (nm)

glass 110 nm 250 nm 370 nm 1100 nm

T % vs. coating thickness

Superhydrophilic and superhydrophobic surfaceSuperhydrophilic and superhydrophobic surface optical property

Particle diameter vs. T %

14.6nm 18.8nm 7.6nm 7.6nm

Particle diameter vs. CA, roughness

CA 140º CA 138º CA 127º CA 123º

Outline

1.Background

2.Our Work

Transparent superhydrophilic and Ultra-hydrophobic

coatings with anti-fogging & anti-reflective properties

3. Applications in solar cell3. Applications in solar cell

Performance of AR coating on solar cell

4. Conclusion

Solar energy > 25% for total energy in 2050 GDP>100000billion （ RMB ）

Based on JRC Report 2004,

Where to for solar cell? Where to for solar cell?

BulkBulkThin-filmThin-film

?

The Third GenerationThe Third GenerationThe Second Generation Generation

The First GenerationGeneration

Size （ mm ）： 1580*808*50 Power: 170WProduction Ability: 20,000,000M2/y

An approach enhanced energy efficiency ---Anti-reflection(AR) glass for solar cell

300 400 500 600 700 80080

85

90

95

100tr

an

smitt

an

ce(%

)

Wavelength(nm)

A coated on both sides B uncoated glass

Transmittance: 92 ～ 96.5% in visible spectrum region

The effect of antireflection film on the The effect of antireflection film on the power output of solar cellpower output of solar cell

Incidence angle Incidence angle vs.vs. the power output the power output

Power increase Power increase

3.8-8.5%3.8-8.5%

30o

60o

0o

Durability of the AR coatingDurability of the AR coating

Item Adhesion Pensile hardness Anti steel wool

Adhesion after Boiled in 80˚C water for1 hr

Condition 3M tap 1Kg 350g,10 times

3M tap

Results 100/100 3H ok 100/100 ， no fogging

A facile method for fabricating transparent

mulitifunctional film based on nanotechnology

Superhydrophobic or superhydrophilic modification

render the coating antifogging/self-cleaning properties

The antireflection film can increase the power output

of solar cell and can product in industrial-scale

Conclusion

Next projectdevelop AR film on flexible substrate and TFT display

international cooperation

Acknowledgement:

Thank the NSFC and CAS Innovation Project for financial

support.

Many thanks for the colleagues: Taiyue Glass, CEEG

(Shanghai) and Chaori Solar Science & Technology Co., Ltd.

Thanks for your attention ！Thanks for your attention ！

Special issue for ICCASSpecial issue for ICCAS

2120

201 )(log4

nnn

nnnA

0n

1n

2n

A ： Amplitude of the Fabry-Pérot finger peaks

,

： refractive index of air

n1 = p·nair + (1-p) ·nframework

： refractive index of coating

： refractive index of substrate

1n

p : porosity of the coatng nframework : refractive index of the framework

p 21.7%.

1.36

Fabry-Pérot vs. refractive index and porosity

Characterizations of wettability: What is contact angle, hysteresis, sliding angle?

Advancing Angle

Receding Angle

Hysteresis : represent for the hardness of slidding off a solid surface for a liquid drop The sliding angle: the difference between the advancing contact angle (θa) and the receding contact angle (θr))

Definition of contact angle

cos

sv sl

lv

John&Sons, New York 1990.

Oxford University Press, Oxford 1984 Langmuir 1998, 14, 5292-5297

Young's equation

02468

10121416

GW

2005 2006 2007 2008 2009 2010

晶硅 非晶硅薄膜 CdTe CIGS Other

95% 92%

70%

87%

78%

67%

Future for different types of solar cellFuture for different types of solar cell