Accepted Manuscript

Title: A Durable, Superhydrophobic, Superoleophobic andCorrosion-Resistant Coating with Rose-Like ZnONanoflowers on a Bamboo Surface

Author: Chunde Jin Jingpeng Li Shenjie Han Jin WangQingfeng Sun

PII: S0169-4332(14)02056-XDOI: http://dx.doi.org/doi:10.1016/j.apsusc.2014.09.065Reference: APSUSC 28721

To appear in: APSUSC

Received date: 13-6-2014Revised date: 30-8-2014Accepted date: 11-9-2014

Please cite this article as: C. Jin, J. Li, S. Han, J. Wang, Q. Sun, A Durable,Superhydrophobic, Superoleophobic and Corrosion-Resistant Coating with Rose-Like ZnO Nanoflowers on a Bamboo Surface, Applied Surface Science (2014),http://dx.doi.org/10.1016/j.apsusc.2014.09.065

This is a PDF file of an unedited manuscript that has been accepted for publication.As a service to our customers we are providing this early version of the manuscript.The manuscript will undergo copyediting, typesetting, and review of the resulting proofbefore it is published in its final form. Please note that during the production processerrors may be discovered which could affect the content, and all legal disclaimers thatapply to the journal pertain.

Page 1 of 31

Accep

ted

Man

uscr

ipt

1

Research Highlights

► Large-scale rose-like ZnO nanoflowers were successfully planted on bamboo

surface.

► The modified bamboo showed durable, superamphiphobic and anticorrosive

properties.

► A facile method for making multifunctional cellulose-based materials was

provided.

Page 2 of 31

Accep

ted

Man

uscr

ipt

2

A Durable, Superhydrophobic, Superoleophobic and

Corrosion-Resistant Coating with Rose-Like ZnO Nanoflowers on a

Bamboo Surface

Chunde Jin, Jingpeng Li, Shenjie Han, Jin Wang, Qingfeng Sun*

Affiliation and address of all authors:

School of Engineering, Zhejiang Agricultural and Forestry University, Lin'an 311300,

P.R. China

*Corresponding author:

Qingfeng Sun

TEL: +86-571- 63732718, FAX: +86-571- 63732718

E-mail: zafuqfsun@foxmail.com

Page 3 of 31

Accep

ted

Man

uscr

ipt

3

Abstract Bamboo remains a vital component of modern-day society; however, its use

is severely limited in certain applications because of its hydrophilic and oleophilic

properties. In this work, we present a method to render bamboo surfaces

superamphiphobic by combining control of ZnO nanostructures and fluoropolymer

deposition while maintaining their corrosion resistance. Large-scale rose-like ZnO

nanoflowers (RZN) were planted on the bamboo surface by a hydrothermal method.

After fluoroalkylsilane (FAS) film deposition to lower the surface energy, the

resulting surface showed superamphiphobicity toward water, oil, and even certain

corrosive liquids, including salt solutions and acidic and basic solutions at all pH

values. The as-prepared superamphiphobic bamboo surface was durable and

maintained its superhydrophobic property with water contact angles ˃ 150° when

stored under ambient condition for two months or immersed in a hydrochloric acid

solution of pH 1 and a sodium hydroxide solution of pH 14 for 3 h at 50 °C.

Keywords: superamphiphobic, superhydrophobic, bamboo surface, hydrothermal

method, ZnO

Page 4 of 31

Accep

ted

Man

uscr

ipt

4

1. Introduction

Surfaces with extreme wettability, such as superhydrophobicity and

superoleophobicity, have attracted significant attention because of their potential

applications in fundamental research and industrial purposes [1-5]. In nature, many

natural superhydrophobic species exist, such as lotus leaves [6], butterfly wings [7],

and water strider legs [8]. Superhydrophobic surfaces are usually fabricated by two

approaches: creating rough structures on intrinsically hydrophobic substrates, or

chemically modifying rough surfaces with low-surface-free-energy materials [9]. Two

distinct theoretical models of Wenzel [10] and Cassie-Baxter [11] have been

developed to explain the wetting of surfaces and to guide the development of

superhydrophobic techniques. It is well known that a superhydrophobic surface may

not be simultaneously superoleophobic. Superoleophobic surfaces may have much

wider potential applications than superhydrophobic surfaces in various fields,

including fluid transfer, antifouling materials, and microfluidic applications [12,13].

However, creating synthetic surfaces with superoleophobic properties has proven to

be much more difficult than creating superhydrophobic surfaces. This is because the

oil liquids possess much smaller surface tensions than that of water, and oil repellent

surfaces require surfaces with even lower surface energies [3,14,15]. To achieve such

a surface would require a coating material with a surface tension value of lower than 6

mN m-1, which is absent in reality (the –CF3 group has a theoretical surface energy of

6 mN m-1) [16]. The fabrication of superoleophobic surfaces can follow the same

design principle: both the surface structure and surface energy must be controlled [17].

Page 5 of 31

Accep

ted

Man

uscr

ipt

5

In past decades, modifications using inorganic materials, such as ZnO, SiO2, TiO2,

and CaCO3 have been employed to reach this goal [18-21]. Among them, ZnO has

established itself as one of the most important electronic and photonic materials

because of its wide direct bandgap (3.37 eV) and large exciton binding energy (60

meV). Its unique electronic, optical, dielectric, piezoelectric and pyroelectric

properties have led to extensive research on photovoltaic cells, ultraviolet lasers,

photoluminescence, EMI shielding, sensors, and capacitors [22-25]. ZnO has also

been considered one of the promising cold-cathode materials due to its negative

electron affinity, chemical stability, and small tip radius of curvature [26]. Thus, this

material is expected to make a hybrid field with nano-carbon; the attachment of ZnO

nanostructures onto nano-carbon can enhance the field electron emission properties

significantly [27]. Fluoropolymer/fluorocarbon materials have one of the lowest

available surface energies, which makes such coatings attractive for

superamphiphobic surfaces [28]. So far, numerous research papers referring to

superamphiphobic surfaces have appeared, but the superamphiphobic surfaces were

primarily fabricated on substrates such as copper, zinc, aluminum, steel, silicon wafer,

glass, carbon, cotton fabric and wood. Zhu et al. [12] developed a simple

solution-immersion technique for the fabrication of superamphiphobic surface on a

copper sheet. After fluorination, the surface became super-repellent toward water and

several organic liquids possessing much lower surface tension than water. Xu et al.

[29] fabricated a superamphiphobic Zn surface by galvanic replacement reactions.

The superamphiphobic Zn surface obtained has remarkable chemical stability even in

Page 6 of 31

Accep

ted

Man

uscr

ipt

6

corrosive solutions over a wide range of pH values. Liu et al. [30] prepared

superhydrophobic surfaces on zinc, silicon, and steel substrates by a simple

solution-immersion technique. Banerjee et al. [31] reported that a very thin layer of

carbon nanoflakes can drastically enhance the FE properties of the underlying SiNWs

as well as the hydrophobicity. Ganesh et al. [32] created a robust superamphiphobic

coating on glass substrates. Chattopadhyay et al. [33] successfully prepared

superhydrophobic amorphous carbon films with various nanostructured surfaces using

plasma-enhanced CVD (PECVD), indicating that the deposition pressure was one of

the most important and easily tuned parameters in controlling the growth morphology

of the carbon materials deposited using PECVD. Xiong et al. [34] used a diblock

copolymer consisting of a sol−gel-forming block and a fluorinated block to coat

cotton fabrics that were highly oil- and water-repellent. Hsieh et al. [35] fabricated

fluorine-containing silica films on wood substrates, which exhibit good repellency for

water and sunflower oil. Therefore, designing surfaces for the dewetting of liquids,

such as water, oil and even for some corrosive liquids, are of both academic and

practical interest. To the best of our knowledge, no reports about the production of

superamphiphobic surfaces on bamboo surfaces exist. A durable, superhydrophobic,

superoleophobic and corrosion-resistant coating with rose-like ZnO nanoflowers on

the bamboo surface was successfully fabricated in this work.

Here, we develop a simple new technique to design and fabricate a

superamphiphobic surface on a bamboo substrate by combining the control of the

ZnO nanostructures and fluoropolymer deposition, and we extend our earlier work. In

Page 7 of 31

Accep

ted

Man

uscr

ipt

7

the initial step, large-scale rose-like ZnO nanoflowers (RZN) were fabricated on the

bamboo surface by a hydrothermal method. In the second step, the surface was

fluorinated by self-assembling with fluoroalkylsilane (FAS) to obtain a

superamphiphobic surface. Compared with the traditional approaches, this method is

simple and the procedure is convenient to operate. Moreover, the resulting

superamphiphobic surface exhibited enhanced superamphiphobicity toward water, oil,

and even several corrosive liquids, including salt solutions and acidic and basic

solutions at all pH values. Furthermore, the stability and durability of the

superamphiphobic surface were also studied.

2. Materials and Methods

2.1. Materials

All chemicals were supplied by Shanghai Boyle Chemical Company Limited and

used as received. Moso bamboo slices (L × T × R) of 40 mm × 20 mm ×3 mm were

ultrasonically rinsed in deionized water and then acetone for 30 min, and then they

were completely dried in the oven at 60 °C for 24 h.

2.2. Fabrication of rose-like ZnO nanoflowers on the bamboo surface

In a typical synthesis process, a zinc acetate dihydrate (Zn(CH3COO)2·2H2O, ZnAc)

solution in methanol (0.75 M) was added slowly to a solution of monoethanolamine

(NH2CH2CH2OH, MEA) with a volume ratio of 1:1 at room temperature. The

resulting mixture solutions were then stirred for 30 min at 60 °C using a magnetic

stirrer until a homogeneous and stable colloidal solution were formed. Bamboo slices

were coated by the ZnO colloid solution through a repeated dip-coating process. The

Page 8 of 31

Accep

ted

Man

uscr

ipt

8

bamboo slices obtained were immersed into the ZnO colloid solution for 5 min. Next,

the bamboo slices were dried at 80 °C for 5 hours using a drying oven. The

procedures from dip-coating to drying were repeated five times to obtain multilayer

films. Then, the reaction solution was prepared by the following procedure: equimolar

aqueous solutions (0.05 M) of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and

hexamethylenetetramine (C6H12N4, HMTA) were prepared in a vessel under constant

stirring, and then, 0.04 M sodium dodecyl sulfonate (NaC12H25SO3, SDS) was added.

The mixed solution was vigorously stirred for 30 min until it became clear and then

was transferred into a Teflon-lined autoclave. The hydrothermal treatments were

performed at 95 °C for 1 h. Then, the samples were collected and rinsed with distilled

water several times. Finally, the samples were dried at 60 °C for 48 h.

2.3. FAS modification

To reduce the surface energy on the bamboo substrate, the surface of the

as-prepared samples were chemically modified with fluoroalkylsilane (FAS). The

samples were immersed in a 1.0 wt % ethanol solution of FAS, which had been

hydrolyzed by the addition of a fivefold molar excess of water. After strong stirring

for 24 h at room temperature, the samples were dried in air and heated at 80 °C for 5 h

in an oven.

The experimental procedure for the preparation of the superamphiphobic bamboo

surface was displayed in Fig. 1. The process for FAS treatment was as follows. First,

it was a necessary that all of the Si-OCH3 groups underwent hydrolysis, causing the

elimination of CH3OH and the formation of Si-OH groups, as shown in process (a).

Page 9 of 31

Accep

ted

Man

uscr

ipt

9

Then, the Si-OH groups were attached onto the RZN via the hydrogen bonds through

the self-assembly process (b).

2.4. Characterization

The morphology of the samples was observed by scanning electron microscopy

(SEM, FEI, Quanta 200). The chemical compositions of the untreated and treated

wood were measured by energy dispersive spectroscopy (EDS, attached to the SEM).

The crystalline structures were identified by X-ray diffraction (XRD, Rigaku, D/MAX

2200) operating with Cu K radiation ( = 1.5418 Å) at a scan rate (2 ) of

4°/min with an accelerating voltage of 40 kV and an applied current of 30 mA ranging

from 5° to 80°. FTIR spectra for the wood samples were recorded using FTIR

(Magna-IR 560, Nicolet). The contact angle (CA) was measured on an OCA40

contact angle system (Dataphysics, Germany) at r.t. with a droplet volume of 5 μL. An

average of five measurements taken at different positions on each sample was applied

to calculate the final CA.

3. Results and Discussion

Fig. 2 showed the XRD patterns of the samples obtained. In Fig. 2a, the

characteristic peaks at 16° and 22° were assigned to represent the crystalline region of

the cellulose of the pristine bamboo [36, 37], but no obvious characteristic peaks

existed for ZnO. After the hydrothermal process, all of the diffraction peaks except for

the characteristic peaks of the pristine bamboo could be indexed to wurtzite-type ZnO

(JCPDS card No. 36-1451). No characteristic peaks from other phases of ZnO were

Page 10 of 31

Accep

ted

Man

uscr

ipt

10

found (Fig. 2b), suggesting that the RZN had a high phase purity and was completely

composed of wurtzite crystals.

EDS spectra of the pristine bamboo, the ZnO-coated bamboo, and the ZnO-coated

bamboo surface modified by FAS were presented in Fig. 3. As shown in Fig. 3a, the

elements carbon, oxygen, and gold could be detected from spectra of the pristine

bamboo. Gold originated from the coating layer used during the SEM observation,

whereas carbon and oxygen were from the bamboo substrate. In addition to the signal

from the elements carbon and oxygen, a signal from zinc was present in the spectrum

of the ZnO-coated bamboo (Fig. 3b), and no other elements were detected, implying

that the nanostructures were primarily ZnO. After modification with FAS, the

elements fluorine and silicon could also be probed in the EDS spectrum (Fig. 3c), and

no other elements were detected, which confirmed that the superamphiphobic surface

had been successfully prepared on the bamboo surface.

Fig. 4 showed the FTIR spectrum of (a) the original bamboo and (b) the bamboo

modified by FAS. In Fig. 4b, peaks are shown in the broad adsorption band at

3380-3440 cm-1, which were attributed to the O-H stretching vibration of

hydrogen-bonded hydroxyl groups or absorbed water [38, 39]. In the high-frequency

region, two strong absorption peaks existed at 2919 and 2852 cm-1, which stem from

the -CH3 and -CH2 symmetrical stretching vibrations and asymmetrical stretching

vibrations, respectively [40], indicating the existence of a long-chain alkyl group on

the bamboo surface. An absorption band also existed at 1195 cm-1, the intensity of

which was confirmed by a strong F-C band [41], which was FAS incorporated into

Page 11 of 31

Accep

ted

Man

uscr

ipt

11

the ZnO surface. Another small peak appearing at approximately 818 cm-1 was

associated with the bending mode of Si-O. In addition, there was a strong adsorption

peak at approximately 500 cm-1 in Fig. 4b, which was the characteristic adsorption

peak of ZnO [40, 42].

Fig. 5 showed the surface morphology of the pristine bamboo and the rose-like

ZnO nanoflowers on the bamboo surface at low and high magnification, respectively.

As shown in Fig. 5a, the microstructures of the pristine bamboo could be clearly

observed, which created a rough surface. The bamboo fibers with diameters of

approximately 5~20 µm could be measured from the SEM image. It was observed

that the surface is densely covered with ZnO nanostructures after the hydrothermal

process (Fig. 5b). Amazingly, the SEM images showed rose-like ZnO nanostructures,

similar to that observed in the inset (Fig. 5c). SEM imaging at higher magnification

revealed that the diameter of the rose-like ZnO nanoflowers was 2-5 μm, which

formed nanoscale roughness on the bamboo surface. Although the roughness of the

surface was improving, the surface retained its superhydrophilic property. Wu et al.

[43] and Ding et al. [44] obtained a superhydrophilic ZnO surface with a contact

angle or approximately zero. The roughness of the surface played a role in fabricating

a superhydrophobic surface [45, 46]. Therefore, the rose-like ZnO nanoflowers

provided the necessary texture to enable the formation of a superhydrophobic surface.

There was no observable change in the surface structure for the as-prepared

samples after fluorination using FAS. However, the wettability of the bamboo surface

changed from superhydrophilic to superamphiphobic. FAS modification endowed the

Page 12 of 31

Accep

ted

Man

uscr

ipt

12

surface with excellent super-repellency toward water, oil, and even several corrosive

liquids, including salt solutions and acidic and basic solutions at all pH values. This is

because the high surface concentration of –CF2 and –CF3 groups provided the low

surface energy to achieve superamphiphobicity [47]. Fig. 6 displayed contact angle

profiles of several typical liquids, and Table 1 listed the CA and SA values. The

bamboo substrate exhibited superamphiphobicity. As shown in Fig. 6 and Table 1,

water, salt, alkali, acid, and lubrication oil droplets exhibited spherical shapes on the

bamboo surface and easily roll off at sliding angles lower than 15. The surface was

also strongly repellent to hexadecane, the CA of which was approximately 150. It

should be noted that this fabrication method makes it possible to fabricate a

superoleophobic surface on a bamboo substrate.

To provide a more visible demonstration of the superamphiphobicity, the

as-prepared samples were displayed in Fig. 7. It is well known that pristine bamboo is

hydrophilic. Although the pristine bamboo possesses a low density and light weight, it

can sink below the water interface because of its hydrophilicity and absorption ability

toward water. In our case, shown in Fig. 7c, the obtained bamboo (the right side of the

figure) could stand easily on the surface of the water, which could be attributed to its

superhydrophobicity. The left side of Fig. 7c showed the pristine bamboo, which was

obvious hydrophilic. When the superhydrophobic bamboo was immersed into water

by an external force, the bamboo surfaces were surrounded by air bubbles, exhibiting

a silver mirror-like surface (Fig. 7a). After releasing the external force, the

superhydrophobic bamboo would float immediately on the water without absorbing

Page 13 of 31

Accep

ted

Man

uscr

ipt

13

any water and finally would stand on the surface of the water (Fig. 7b). This implied

that the superhydrophobic surface could be used to protect the bamboo against the

water in the outdoors. In addition to the water repellency, the resultant bamboo also

exhibited stable repellency toward oil and corrosive liquids, such as engine oil and

acidic, salt, and alkali solutions. Fig. 7d provided an optical image of several typical

liquids on the pristine bamboo, from left to right: engine oil, hydrochloric acid

solution (pH = 1), NaCl solution (pH = 7), NaOH solution (pH = 14), and water

droplets. The probing liquids could be easily absorbed by the pristine bamboo; the

CAs of the probing liquids were approximately zero. After chemical modification

with FAS, the contact angles of the probing liquids were changed from nearly zero

(Fig. 7d) to approximately 153° (Fig. 7e). The probing liquids displayed perfectly

spherical shapes on the bamboo surface and could easily roll off the surface. To our

surprise, the static contact angles were almost unchanged over a wide range of pH

values from 1 to 14. Fig. 4f showed the representative digital image of acidic (left, pH

= 1), salt (middle, pH = 7), and basic (right, pH = 14) droplets on the bamboo surface.

All of the solution droplets with perfect spherical shapes were standing uniformly on

the bamboo surface, exhibiting stable wettability even toward many corrosive

solutions.

To evaluate the stability and durability of the superhydrophobic bamboo surface,

the as-prepared superhydrophobic bamboo was maintained under ambient conditions

for two months. The water contact angles of the superhydrophobic surface showed no

obvious change, retaining their remarkable spherical shape (Fig. 8a). In addition, after

Page 14 of 31

Accep

ted

Man

uscr

ipt

14

being placed into a NaOH solution of pH 14 (Fig. 8b) and a hydrochloric acid solution

of pH 1 (Fig. 8c) for 3 h at 50 °C, the surface still retained its superhydrophobicity,

and the water contact angles were larger than 150°. The results revealed that the

resultant bamboo showed obviously remarkable stability and perfect durability for

mild acid and strong base and further exhibited stable repellency toward corrosive

liquids, such as mild acidic, salt, and alkali solutions. Therefore, this work may open

up a new field of application of bamboo resources, and the multifunctional

superhydrophobic surface can protect the bamboo against acid rain in the outdoors.

4. Conclusions

In this study, we developed a novel method to fabricate a durable,

superhydrophobic, superoleophobic and corrosion-resistant coating with rose-like

ZnO nanoflowers on the bamboo surface. The large-scale rose-like ZnO nanoflowers

were first planted on the bamboo surface by a hydrothermal method to increase the

surface roughness, and then the surface was subsequently treated with a low

surface-energy material of FAS. After modification with FAS, the superhydrophobic

bamboo surface obtained not only had excellent durability toward water but also

displayed super-repellency toward oil and corrosive solutions. In addition, the

as-prepared superamphiphobic bamboo surface was durable and retained its

superhydrophobic with water contact angles ˃ 150° when stored under ambient

conditions for two months or immersed in a hydrochloric acid solution of pH 1 and a

sodium hydroxide solutions of pH 14 for 3 h at 50 °C. With a multifunctional

superamphiphobic surface on bamboo substrates, bamboo resources could potentially

Page 15 of 31

Accep

ted

Man

uscr

ipt

15

be used in a wider range of applications. We also expect that this method could be

widely used for other cellulose-based materials with multifunction integration.

Acknowledgement

The work was financially supported by the Pre-research Project of Research Center

of Biomass Resource Utilization, Zhejiang A & F University (2013SWZ01-03).

References

[1] X. Zhang, Z. Li, K. Liu, L. Jiang, Bioinspired Multifunctional Foam with Self-Cleaning and

Oil/Water Separation, Adv. Funct. Mater. 23 (2013) 2881-2886.

[2] H. Wang, Y. Xue, J. Ding, L. Feng, X. Wang, T. Lin, Durable, Self-Healing Superhydrophobic

and Superoleophobic Surfaces from Fluorinated-Decyl Polyhedral Oligomeric

Silsesquioxane and Hydrolyzed Fluorinated Alkyl Silane, Angew. Chem. Int. Ed. 50 (2011)

11433-11436.

[3] A. Tuteja, W. Choi, M. Ma, J.M. Mabry, S.A. Mazzella, G.C. Rutledge, G.H. McKinley, R.E.

Cohen, Designing superoleophobic surfaces, Science. 318 (2007) 1618-1622.

[4] J. Song, Y. Lu, S. Huang, X. Liu, L. Wu, W. Xu, A simple immersion approach for fabricating

superhydrophobic Mg alloy surfaces, Appl. Surf. Sci. 266 (2013) 445-450.

[5] X. Zhou, Z. Zhang, X. Xu, X. Men, X. Zhu, Fabrication of super-repellent cotton textiles with

rapid reversible wettability switching of diverse liquids, Appl. Surf. Sci. 276 (2013) 571-577.

[6] L. Jiang, Y. Zhao, J. Zhai, A Lotus-Leaf-like Superhydrophobic Surface: A Porous

Microsphere/Nanofiber Composite Film Prepared by Electrohydrodynamics, Angew. Chem.

Int. Ed. 116 (2004) 4438-4441.

[7] Y. Zheng, X. Gao, L. Jiang, Directional adhesion of superhydrophobic butterfly wings, Soft.

Page 16 of 31

Accep

ted

Man

uscr

ipt

16

Matter. 3 (2007) 178-182.

[8] X. Gao, L. Jiang, Biophysics: water-repellent legs of water striders, Nature 432 (2004) 36-36.

[9] X. Zhou, Z. Zhang, X. Xu, J. Yang, X. Men, X. Zhu, Facile fabrication of recoverable and

stable superhydrophobic polyaniline films, Colloids Surf. A. 412 (2012) 129-134.

[10] R.N. Wenzel, Resistance of solid surfaces to wetting by water, Ind. Eng. Chem. 28 (1936)

988-994.

[11] A. Cassie, S. Baxter, Wettability of porous surfaces, Trans. Faraday. Soc. 40 (1944) 546-551.

[12] X. Zhu, Z. Zhang, X. Xu, X. Men, J. Yang, X. Zhou, Q. Xue, Facile fabrication of a

superamphiphobic surface on the copper substrate, J. Colloid Interf. Sci. 367 (2012) 443-449.

[13] Z. Zhang, X. Zhu, J. Yang, X. Xu, X. Men, X. Zhou, Facile fabrication of superoleophobic

surfaces with enhanced corrosion resistance and easy repairability, Appl. Phys. A. 108 (2012)

601-606.

[14] A. Tuteja, W. Choi, G.H. McKinley, R.E. Cohen, M.F. Rubner, Design parameters for

superhydrophobicity and superoleophobicity, Mrs Bull. 33 (2008) 752-758.

[15] M. Liu, S. Wang, Z. Wei, Y. Song, L. Jiang, Bioinspired design of a superoleophobic and low

adhesive water/solid interface, Adv. Mater. 21 (2009) 665-669.

[16] W. Wu, X. Wang, D. Wang, M. Chen, F. Zhou, W. Liu, Q. Xue, Alumina nanowire forests

via unconventional anodization and super-repellency plus low adhesion to diverse liquids,

Chem. Commun. (2009) 1043-1045

[17] F. Xia, L. Jiang, Bio-Inspired, Smart, Multiscale Interfacial Materials, Adv. Mater. 20 (2008)

2842-2858.

[18] H.B. Jo, J. Choi, K.J. Byeon, H.J. Choi, H. Lee, Superhydrophobic and superoleophobic

Page 17 of 31

Accep

ted

Man

uscr

ipt

17

surfaces using ZnO nano-in-micro hierarchical structures, Microelectronic Eng. 116 (2014)

51-57.

[19] J. Li, H. Wan, Y. Ye, H. Zhou, J. Chen, One-step process to fabrication of transparent

superhydrophobic SiO2 paper, Appl. Surf. Sci. 261 (2012) 470-472.

[20] V.A. Ganesh, S.S. Dinachali, A. S. Nair, S. Ramakrishna, Robust superamphiphobic film

from electrospun TiO2 nanostructures, ACS Appl. Mater. Interfaces 5 (2013) 1527-1532.

[21] G.G. Wang, L.Q. Zhu, H.C. Liu, W.P. Li, Self-assembled biomimetic superhydrophobic

CaCO3 coating inspired from fouling mineralization in geothermal water, Langmuir 27 (2011)

12275-12279.

[22] R. Maity, S. Das, M. K. Mitra, K.K. Chattopadhyay, Synthesis and characterization of ZnO

nano/microfibers thin films by catalyst free solution route, Physica E 25 (2005) 605-612.

[23] W.L. Song, M.S. Cao, B. Wen, Z.L. Hou, J. Cheng, J. Yuan, Synthesis and characterization

of ZnO nano/microfibers thin films by catalyst free solution route, Physica E 47 (2012)

1747-1754.

[24] M. Law, L.E. Greene, J.C. Johnson, R.J. Sayakally, P.D. Yang, Nanowire dye-sensitized

solar cells, Nat. Mater. 4 (2005) 455-459.

[25] M.F. Hossain, T. Takahashi, Microstructured ZnO photoelectrode grown on the

sputter-deposited ZnO passivating-layer for improving the photovoltaic performances, Mater.

Chem. Phys. 124 (2010) 940-945.

[26] U.N. Maiti, S.F. Ahmed, M. K. Mitra, K.K. Chattopadhyay, Novel low temperature synthesis

of ZnO nanostructures and its efficient field emission property, Mater. Res. Bull. 44 (2009)

134-139.

Page 18 of 31

Accep

ted

Man

uscr

ipt

18

[27] D. Nawn, D. Banerjee, K.K. Chattopadhyay, Zinc oxide nanostructure decorated amorphous

carbon nanotubes: An improved field emitter, Diam. Relat. Mater. 34 (2013) 50-59.

[28] Y. Liu, Y. Xiu, D.W. Hess, C. Wong, Silicon surface structure-controlled oleophobicity,

Langmuir 26 (2010) 8908-8913.

[29] X. Xu, Z. Zhang, F. Guo, J. Yang, X. Zhu, X. Zhou, Q. Xue, Superamphiphobic

self-assembled monolayer of thiol on the structured Zn surface, Colloids Surf. A. 396 (2012)

90-95.

[30] H. Liu, S. Szunerits, M. Pisarek, W. Xu, R Boukherroub, Preparation of superhydrophobic

coatings on zinc, silicon, and steel by a solution-immersion technique, ACS Appl. Mater.

Inter. 1 (2009) 2086-2091.

[31] D. Banerjee, N.S. Das, K.K. Chattopadhyay, Enhancement of field emission and hydrophobic

properties of silicon nanowires by chemical vapor deposited carbon nanoflakes coating, Appl.

Surf. Sci. 261 (2012) 223-230.

[32] V.A. Ganesh, S.S. Dinachali, A.S. Nair, S. Ramakrishna, Robust superamphiphobic film

from electrospun TiO2 nanostructures, ACS Appl. Mater. Inter. 5 (2013) 1527-1532.

[33] D. Banerjee, S.Mukherjee, K.K. Chattopadhyay, Controlling the surface topology and hence

the hydrophobicity of amorphous carbon thin films, Carbon 48 (2010) 1025-1031.

[34] D. Xiong, G. Liu, E.S. Duncan, Diblock-copolymer-coated water-and oil-repellent cotton

fabrics, Langmuir 28 (2012) 6911-6918.

[35] C-T. Hsieh, B-S. Chang, J-Y. Lin, Improvement of water and oil repellency on wood

substrates by using fluorinated silica nanocoating, Appl. Surf. Sci. 257 (2011) 7997-8002.

[36] Y. Lu, Q. Sun, D. Yang, X. She, X. Yao, G. Zhu, Y. Liu, H. Zhao, J. Li, Fabrication of

Page 19 of 31

Accep

ted

Man

uscr

ipt

19

mesoporous lignocellulose aerogels from wood via cyclic liquid nitrogen freezing-thawing in

ionic liquid solution, J. Mater. Chem. 22 (2012) 13548-13557.

[37] J. Li, Y. Lu, D. Yang, Q. Sun, Y. Liu, H. Zhao, Lignocellulose aerogel from wood-ionic

liquid solution (1-allyl-3-methylimidazolium chloride) under freezing and thawing conditions,

Biomacromolecules 12 (2011) 1860-1867.

[38] Q. Sun, Y. Lu, Y. Liu, Growth of hydrophobic TiO2 on wood surface using a hydrothermal

method, J. Mate. Sci. 46 (2011) 7706-7712.

[39] K. Pandey, A study of chemical structure of soft and hardwood and wood polymers by FTIR

spectroscopy, J. Appl. Polym. Sci. 71(1999) 1969-1975.

[40] Q. Sun, Y. Lu, H. Zhang, D. Yang, Y. Wang, J. Xu, J. Tu, Y. Liu, J. Li, Improved UV

resistance in wood through the hydrothermal growth of highly ordered ZnO nanorod arrays, J.

Mate. Sci. 47 (2012) 4457-4462.

[41] N. Saleema, D.K. Sarkar, D. Gallant, R.W. Paynter, X.G. Chen, Chemical nature of

superhydrophobic aluminum alloy surfaces produced via a one-step process using

fluoroalkyl-silane in a base medium, ACS Appl. Mater. Inter. 3 (2011) 4775-4781.

[42] H. Bhatti, S. Kumar, K. Singh, Structural and optical characterization of hydroxy-propyl

methyl cellulose-capped ZnO nanorods, J. Mate. Sci. 48 (2013) 5536-5542.

[43] J. Wu, J. Xia, W. Lei, B-p. Wang, Fabrication of superhydrophobic surfaces with

double-scale roughness, Mater. Lett. 64 (2010) 1251-1253.

[44] B. Ding, T. Ogawa, J. Kim, K. Fujimoto, S. Shiratori, Fabrication of a super-hydrophobic

nanofibrous zinc oxide film surface by electrospinning, Thin Solid Films 516 (2008)

2495-2501.

Page 20 of 31

Accep

ted

Man

uscr

ipt

20

[45] P. Roach, N.J. Shirtcliffe, M.I. Newton, Progess in superhydrophobic surface development,

Soft. Matter. 4 (2008) 224-240.

[46] X. Zhang, F. Shi, J. Niu, Y. Jiang, Z. Wang, Superhydrophobic surfaces: from structural

control to functional application, J. Mater. Chem. 18 (2008) 621-633.

[47] S.M. Mukhopadhyay, P. Joshi, S. Datta, J. Zhao, P. France, Plasma assisted hydrophobic

coatings on porous materials: influence of plasma parameters, J. Phys. D: Appl. Phys. 35

(2002) 1927.

[48] T. Stoebe, Z. Lin, R.M. Hill, M.D. Ward, H.T. Davis, Superspreading of aqueous

films containing trisiloxane surfactant on mineral oil, Langmuir 13 (1997)

7282-7286.

Page 21 of 31

Accep

ted

Man

uscr

ipt

21

Figure Captions

Fig. 1. Schematic diagrams of the procedure for the preparation of the

superamphiphobic bamboo surface.

Fig. 2. XRD patterns of (a) the pristine-surface bamboo specimens and (b) the

bamboo specimens after the hydrothermal process.

Fig. 3. EDS spectra of (a) the pristine bamboo, (b) the ZnO-coated bamboo, and (c)

the bamboo with the surface modified by FAS.

Fig. 4. FTIR spectra of (a) the original bamboo and (b) the FAS/ZnO-treated bamboo.

Fig. 5. SEM images of (a) the pristine bamboo and the RZN on the bamboo surface at

(b) low magnification and (c) high magnification. The inset is an image of a real rose.

Fig. 6. Contact angle profiles of water, salt, alkali, acid, lubrication oil, and

hexadecane droplets on the superamphiphobic surface.

Fig. 7. (a) Optical image of the superhydrophobic bamboo immersed in water by an

external force, exhibiting a silver mirror-like surface due to the surrounding air

bubbles. (b) Optical image of the superhydrophobic bamboo floating on water after

releasing the external force. (c) Digital image of the pristine bamboo (left) floating

below the water interface and the superhydrophobic bamboo (right) standing on the

water. The pictures of engine oil, hydrochloric acid solution (pH = 1), NaCl solution

(pH = 7), NaOH solution (pH = 14), and water droplets with spherical shapes on the

pristine bamboo (d) and superhydrophobic bamboo surface (e). (f) Optical image of

the front view of the hydrochloric acid solution (pH = 1), NaCl solution (pH = 7), and

NaOH solution (pH = 14) droplets on the superhydrophobic surface.

Page 22 of 31

Accep

ted

Man

uscr

ipt

22

Fig. 8. Images of samples with (a) a storage time under ambient condition for two

months and an immersion time in solutions of pH 14 (b) and pH 1 (c) at 50 °C for 3 h.

Page 23 of 31

Accep

ted

Man

uscr

ipt

23

Fig. 1. Schematic diagrams of the procedure for the preparation of the

superamphiphobic bamboo surface.

Page 24 of 31

Accep

ted

Man

uscr

ipt

24

10 20 30 40 50 60 70 80

2 Theta (deg.)10

0 002

101

102

110

103

112

a: The pristine bamboo

a

b

b: The ZnO-coated bamboo

Rel

ativ

e In

tens

ity

(a.u

.)

Fig. 2. XRD patterns of (a) the pristine-surface bamboo specimens and (b) the

bamboo specimens after the hydrothermal process.

Page 25 of 31

Accep

ted

Man

uscr

ipt

25

Fig. 3. EDS spectra of (a) the pristine bamboo, (b) the ZnO-coated bamboo, and (c)

the bamboo with the surface modified by FAS.

Page 26 of 31

Accep

ted

Man

uscr

ipt

26

4000 3500 3000 2500 2000 1500 1000 500

Wavenumbers (cm-1)

2919

2852

1195 81

8

Tra

nsim

itta

nce

(%)

a

b

Fig. 4. FTIR spectra of (a) the original bamboo and (b) the FAS/ZnO-treated bamboo.

Page 27 of 31

Accep

ted

Man

uscr

ipt

27

Fig. 5. SEM images of (a) the pristine bamboo and the RZN on the bamboo surface at

(b) low magnification and (c) high magnification. The inset is an image of a real rose.

Page 28 of 31

Accep

ted

Man

uscr

ipt

28

Fig. 6. Contact angle profiles of water, salt, alkali, acid, lubrication oil, and

hexadecane droplets on the superamphiphobic surface.

Page 29 of 31

Accep

ted

Man

uscr

ipt

29

Fig. 7. (a) Optical image of the superhydrophobic bamboo immersed in water by an

external force, exhibiting a silver mirror-like surface due to the surrounding air

bubbles. (b) Optical image of the superhydrophobic bamboo floating on water after

releasing the external force. (c) Digital image of the pristine bamboo (left) floating

below the water interface and the superhydrophobic bamboo (right) standing on the

water. The pictures of engine oil, hydrochloric acid solution (pH = 1), NaCl solution

(pH = 7), NaOH solution (pH = 14), and water droplets with spherical shapes on the

pristine bamboo (d) and superhydrophobic bamboo surface (e). (f) Optical image of

the front view of the hydrochloric acid solution (pH = 1), NaCl solution (pH = 7), and

NaOH solution (pH = 14) droplets on the superhydrophobic surface.

Page 30 of 31

Accep

ted

Man

uscr

ipt

30

Fig. 8. Images of samples with (a) a storage time under ambient condition for two

months and an immersion time in solutions of pH 14 (b) and pH 1 (c) at 50 °C for 3 h.

Page 31 of 31

Accep

ted

Man

uscr

ipt

31

Table 1. CA and SA values of the various probing liquids on the obtained surface.

Liquida Static CA () SA ()Water 156 1 5Salt 155 2 5

Alkali 153 1 5Acid 152 1 5

Lubrication oil 151 1 15 2Hexadecane 150 1 18 1

a The value of surface tension for lubrication oil in the manuscript is 31 mN m-1 [48].