Exploiting the hierarchical morphology of single-walled and multi-walled carbon nanotube films for highly hydrophobic coatings

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# Exploiting the hierarchical morphology of single-walled and multi-walled carbon nanotube films for highly hydrophobic coatings

Francesco De Nicola *1,2, Paola Castrucci 1,2, Manuela Scarselli 1,2, Francesca Nanni 3,
Ilaria Cacciotti 4 and Maurizio De Crescenzi 1,2,5

Full Research Paper [Open Access](http://www.beilstein-journals.org/bjnano/about/openAccess.htm)

Address:
1Dipartimento di Fisica, Universitá di Roma Tor Vergata, Via della
Ricerca Scientifica 1, 00133 Roma, Italy, 2 Istituto Nazionale di Fisica

Nucleare, Universitá di Roma Tor Vergata (INFN-Roma Tor Vergata),
Via della Ricerca Scientifica 1, 00133 Roma, Italy, 3 Dipartimento di

Ingegneria dell’Impresa, Universitá di Roma Tor Vergata (INSTM-UdR

Roma Tor Vergata), Via del Politecnico 1, 00133 Roma, Italy,
4Universitá di Roma Niccolò Cusano (INSTM-UdR), Via Don Carlo
Gnocchi 3, 00166 Roma, Italy and 5 Istituto di Struttura della Materia,

Consiglio Nazionale delle Ricerche (ISM-CNR), Via del Fosso del

Cavaliere 100, 00100 Roma, Italy

Email:
Francesco De Nicola * [- fdenicola@roma2.infn.it](mailto:fdenicola@roma2.infn.it)

- Corresponding author

Keywords:

hierarchical structures; hydrophobic surfaces; multi-walled carbon

nanotube; single-walled carbon nanotube; wetting transitions

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

[doi:10.3762/bjnano.6.34](http://dx.doi.org/10.3762%2Fbjnano.6.34)

Received: 12 September 2014

Accepted: 13 January 2015

Published: 02 February 2015

This article is part of the Thematic Series "Self-assembly of

nanostructures and nanomaterials".

Guest Editor: I. Berbezier

License and terms: see end of document.

## Abstract

Self-assembled hierarchical solid surfaces are very interesting for wetting phenomena, as observed in a variety of natural and artifi
cial surfaces. Here, we report single-walled (SWCNT) and multi-walled carbon nanotube (MWCNT) thin films realized by a

simple, rapid, reproducible, and inexpensive filtration process from an aqueous dispersion, that was deposited at room temperature

by a dry-transfer printing method on glass. Furthermore, the investigation of carbon nanotube films through scanning electron

microscopy (SEM) reveals the multi-scale hierarchical morphology of the self-assembled carbon nanotube random networks. More
over, contact angle measurements show that hierarchical SWCNT/MWCNT composite surfaces exhibit a higher hydrophobicity

(contact angles of up to 137°) than bare SWCNT (110°) and MWCNT (97°) coatings, thereby confirming the enhancement

produced by the surface hierarchical morphology.

353

## Introduction

In general, the surface morphology [1] is a crucial parameter for

the fabrication of artificial hydrophobic surfaces and may be

enhanced especially by hierarchical [2-7] and fractal structures

[7,8], possibly allowing for the formation of air pockets to

further impede the penetration of water [9].

In particular, hierarchical surface morphologies are a recent

concept introduced to explain the wetting properties of surfaces

such as plant leaves [2,3], bird feathers [10], and insect legs

[11]. These surfaces are made of a hierarchical micro- and

nanomorphology which improves their wettability.

It is indeed well-established [12,13] that on composite rough

surfaces a hierarchical morphology may induce a wetting tran
sition from Wenzel [1] to Cassie–Baxter [9] state owing to air

trapping. Moreover, this transition may occur by passing

through thermodynamically metastable states [13-16], where

the free energy surface presents one absolute minimum and one

or more local minima separated from the former by large free

energy barriers, as compared to the thermal energy. Metasta
bility can also have a technological importance, as in practice, it

represents a way of extending the range of stability of the

Cassie–Baxter state [14,17]. Conversely, a negative conse
quence of metastability is that it might prevent or slow down

the transition between Wenzel and Cassie–Baxter states [14,17].

Moreover, biomimetics [18,19] may be exploited in order to

realize cutting edge artificial surfaces [2,3,5] that mimicking

natural surface. In this way these surfaces can be optimized for

hydrophobic (lipophilic) and/or hydrophilic (lipophobic) appli
cations.

Motivated by this concept, we report here the fabrication of

highly hydrophobic coatings of self-assembling SWCNTs on

MWCNTs. Since the former are smaller than the latter (about

one order of magnitude), we observed that a surface hierarchy

naturally occurs by depositing layer by layer a SWCNT film

upon a MWCNT film. The particular two-fold hierarchical

morphology of the surface, resembling that observed in lotus

leaves [3] and rose petals [2] in which micropapillae are made

of nanopapillae, improves the hydrophobic behavior of carbon

nanotube coatings compared to bare SWCNT and MWCNT

films. Moreover, we report for the first time the experimental

Wenzel/Cassie–Baxter phase diagram [8,12,17] for a carbon

nanotube surface, showing that the transition between the

Wenzel and Cassie–Baxter states occurs by passing through

metastable states.

Generally, carbon nanotubes [20,21] are the one-dimensional
allotropic form of carbon with cylindrical symmetry and a sp 2

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

lattice. Carbon nanotubes may be single-walled or multi-walled

depending on the number of coaxially arranged graphite planes.

Moreover, owing to their honeycomb lattice, carbon nanotubes

are inherently hydrophilic (the contact angle of graphite with

water being approx. 86° [22]) but apolar. However, by surface

functionalization or textured arrangement it can be possible to

realize carbon nanotube films which offer versatility, high

stability, and multi-functionality owing to their exceptionally

unique properties [21], making their usage widespread in

hydrophobic surface applications [4,5,23-35].

Furthermore, self-assembly hierarchical nanostructured ma
terials [36-39] are nowadays investigated as a consequence of

their tunable peculiar properties and the easy, highly repro
ducible, and low-cost fabrication. In addition, they are ideal

low-dimensional materials for the fabrication of high aspect

ratio and large area devices [40].

## Results and Discussion

The films obtained from the process described in the

Experimental section are porous random networks of

SWCNTs and MWCNTs that exhibit a hierarchical

morphology made of micro- and nanostructures, as

evident from SEM micrographs in Figure 1. From SEM image

analysis (see Experimental section), we estimated the pore

radius ρ and the bundle diameter _d_ of the SWCNT and

MWCNT random networks. The obtained results are reported in

Table 1 together with the SWCNT microstructure area _S_

and height _h_ . However, in the case of MWCNT films, no

microstructures were observed. It is noteworthy that the charac
teristic dimension _d_ of MWCNTs is bigger by about one order

than that of SWCNTs.

In particular, we considered the microstructures shown in

Figure 1c as ripples randomly distributed within the film. Such

self-assembly occurs by an out-of-plane bending process during

evaporative drying of single-walled carbon nanotube film

during its preparation [36,37,41]. The out-of-plane assembly is

the result of the competition between attractive capillary forces

and bending stress due to the elasticity of SWCNT film. Once

the liquid is completely evaporated, a pattern of micrometer
sized randomly shaped islands is formed. If, after complete

evaporation, there is a balance between adhesion and elastic

energy, the microstructures are in a stable bent configuration

with respect to further wetting–dewetting cycles. This self
assembly leads to an intrinsic hierarchical microstructured

(ripples) and nanostructured (carbon nanotubes) roughness able

to enhance the wetting properties of the SWCNT film.

Conversely, the MWCNT sample (Figure 1d) just aligned verti
cally out of plane.

354

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

Figure 1: Scanning electron micrographs of SWCNT (a,c) and MWCNT (b,d) films at different magnifications 200,000× (a,b), and 10,000× (c,d). In the
images taken at grazing incidence (c,d) it is possible to observe that SWCNTs (c) self-assemble in ripples forming several microstructures, while
MWCNTs (d) just aligned in the out-of-plane vertical direction. (d) Black areas are holes in the film.

Table 1: Experimental results of SEM analysis and contact angle measurements.

sample ρ (nm) _d_ (nm) _S_ (μm 2 ) _h_ (μm) θ (°)

SWCNT 2–8 4–8 0.003–0.007 1.6–11.7 110 ± 3

MWCNT 40–44 34–84   -   - 97 ± 8

SWCNT/MWCNT 47–51 - 7.3–13.7 3.2–61.6 129 ± 8

MWCNT/SWCNT 5–7 - 7.7–14.3 2.3–76.2 103 ± 7

Furthermore, we induced an extrinsic hierarchical architecture

by depositing a SWCNT film on a MWCNT film (SWCNT/

MWCNT) and in reverse order (MWCNT/SWCNT), as shown

in Figure 2. From SEM image analysis, we obtained the two

film pore diameters, microstructure areas and heights, as

reported in Table 1. In both cases, a self-assembly led to the for
mation of several huge microstructures as compared to the those

of the SWCNT films.

Moreover, in Figure 3a and Figure 3b, images of water droplets

cast on our SWCNT and MWCNT films are shown, with

average contact angle values of θ = 110 ± 3° and θ = 97 ± 8°,

respectively. These results can be ascribed to the particular

morphology of both the films induced by the inherent prop
erties of the carbon nanotubes (e.g., self-assembly, nanotube

diameter and spatial orientation) and film preparation method.

We also found that for the SWCNT/MWCNT sample the

extrinsic surface hierarchy increased the hydrophobicity of the

MWCNT sample, exhibiting a highly hydrophobic average

contact angle value of θ = 129 ± 8° (Figure 3c), comparable to

the values of PTFE (Teflon) of 108–118° [22,42]. Conversely,

for the MWCNT/SWCNT sample (Figure 3d) a slightly

decrease of the average contact angle value (θ = 103 ± 7°) with

respect to the bare SWCNT sample was encountered.

Our results, summarized in Table 1, may be interpreted on the

basis of the microstructure characteristic dimensions _S_ and _h_ . In

both the SWCNT/MWCNT and MWCNT/SWCNT samples the

microstructure characteristic dimensions are comparable with

those of lotus and rose micropapillae [2,3]. Nevertheless, in the

latter the extrinsic hierarchical morphology is reversed (bigger

MWCNT scale superimposed on the smaller SWCNT scale),

thereby losing the hierarchical fakir effect [7,43]. Therefore, the

SWCNT/MWCNT sample has the best hydrophobic behavior

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_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

Figure 2: Scanning electron micrographs of SWCNT/MWCNT (a,c) and MWCNT/SWCNT (b,d) films at different magnifications 200,000 × (a,b),
1,000× (c,d), and 10,000× (c,d insets). In the images taken at grazing incidence (c,d and insets), it is possible to observe that in both cases the selfassembly forms several huge microstructures. (c,d insets) Details of the microstructures showing a hierarchical morphology very similar to that of
lotus leaves and rose petals.

high contact angle hysteresis, which pinned the droplets to the

surface [2].

In order to better understand the origin of the enhancement

provided by the SWCNT/MWCNT film over the MWCNT

film, we characterized the wetting state of the former composite

surface with respect to the latter. In Figure 4a, we report the

contact angle of both films as a function of the concentration in

volume percent of ethanol in water. It is possible to observe that

since ethanol has a lower liquid–vapor surface tension
(γLV = 22 mJ·m −2 ) than water (γLV = 72 mJ·m −2 ), the higher the
ethanol concentration in water, the lower the surface tension of

the solution. Furthermore, the contact angle is generally propor
tional to the liquid surface tension by the Young’s relation

Figure 3: Water droplets cast on SWCNT (a), MWCNT (b), SWCNT/
MWCNT (c), and MWCNT/SWCNT (d) films. Owing to the rough and
porous surface of the samples, water drops exhibit different contact
angle values, depending on the exact place at the surface on which
they are cast. In this case, the contact angle can be only defined on
average.

because is the most biomimetic. We remark that the large devia
tion of the average value of the contact angle is due to the

highly rough and porous surface of our samples. In addition, no

roll-off angle value could be measured, evidently due to the

(1)

where γSV and γSL are the solid–vapor and solid–liquid surface
tensions, respectively. Therefore, also the contact angles of the

carbon nanotube films decrease with the decrease in surface

tension of the liquid droplet. This phenomenon is connected to

the lipophilicity of the apolar surface of the carbon nanotube.

Indeed, on our carbon nanotube films no contact angle (θ ≈ 0)

can be measured for pure ethanol droplets. Therefore, we

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_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

Figure 4: (a) Contact angle of the SWCNT/MWCNT (blue squares) and MWCNT (red dots) films as a function of ethanol concentration in water.
(b) Wenzel/Cassie–Baxter phase diagram of the SWCNT/MWCNT surface respect to the MWCNT surface. Wetting states are studied changing
the liquid surface tension by adding different ethanol concentrations in water. Wenzel regime (green solid line) fit reports a roughness factor
_r_ = 1.08 ± 0.01, while lipophilic (blue solid line) and hydrophobic (red solid line) Cassie–Baxter regime fits report respectively a liquid fraction

and an air fraction . The Wenzel/Cassie–Baxter transition point in the hydrophobic regime is the intersection between
the red and green solid lines, while in the lipophilic regime it is the intersection between the blue and green solid lines. Error bars are standard deviations.

investigated all the wetting phenomena occurring on our carbon

nanotube surface, exploring all the wetting states. We further

noted that for θ ≈ 56°, (cos θ ≈ 0.56) there is an intersection

point between the two curves in Figure 4a, beyond which the

SWCNT/MWCNT surface becomes more lipophilic than the

MWCNT surface. That point corresponds to the transition point

from Wenzel to Cassie–Baxter state in the lipophilic region of

the Wenzel/Cassie–Baxter phase diagram, as confirmed from

the plot (first quadrant) in Figure 4b. However, the plot in

Figure 4b shows that the transition occurs by passing through

metastable states with an abrupt change in the wetting state. We

fitted our data with the lipophilic Cassie–Baxter’s equation [9]

(2)

with the surface solid fraction, the surface fraction wetted
by the liquid, θ _*_ the SWCNT/MWCNT surface contact angle

and θ the MWCNT surface contact angle. We obtained from fit

a liquid fraction in contact with the droplet.

However, we remark that these metastable Cassie–Baxter states

coexist with the Wenzel states, which are stable because lower

in surface free energy.

Moreover we fitted our data in Figure 4b with Wenzel’s equa
tion [1]

(3)

where _r_ is the roughness factor (i.e, the ratio between the actual

wet surface area and its projection on the plane). Interestingly,

the fit returned _r_ = 1.08 ± 0.01, which means that substantially

the SWCNT/MWCNT sample has the same roughness of the

MWCNT sample. It is noteworthy that in our case _r_ ≈ 1 does

not mean that the surface is smooth, because we are not

comparing the SWCNT/MWCNT with its corresponding

smooth surface with the same chemistry, such as plain graphite.

However, in the latter case we would have had a high rough
ness factor [41]. Therefore, we can exclude a roughness

enhancement, which we did not observe, as the reason of a such

improvement in hydrophobic behavior the SWCNT/MWCNT

sample over the MWCNT sample. In addition, from the rela
tion [44]

(4)

we can infer that the lipophilic Wenzel/Cassie–Baxter tran
sition point is cos θ′ = 0.88 (the intersection between the blue

and green solid lines in Figure 4b), which is beyond the

measured data, thus confirming that the achieved lipophilic

Cassie–Baxter states are metastable.

Conversely, in the hydrophobic region (third quadrant of the

plot) we observe a sharp discontinuity beyond cos θ = 0,

confirming again that the transition between the Wenzel and

Cassie–Baxter states is not continuous, but it undergoes

metastable states which slow down the dewetting process. Actu
ally, by fitting our data in Figure 4b with the hydrophobic

Cassie–Baxter’s equation

(5)

357

we obtained an air surface fraction below the

liquid droplet. Furthermore, by the relation [44]

(6)

we can infer that the hydrophobic Wenzel/Cassie–Baxter tran
sition point is cos θ′′ = −0.85 (the intersection between the red

and green solid lines in Figure 4b), which is beyond the

measured data, thus confirming that the achieved hydrophobic

Cassie–Baxter states are metastable. Nevertheless, this result

suggests a consistent air pocket formation [9].

Therefore, we can assert that the only cause of the improved

hydrophobicity/lipophilicity of the SWCNT/MWCNT film over

the MWCNT film, is the fakir effect induced by the two-fold

hierarchical morphology given by the SWCNT film superim
posed on the MWCNT film. This particular morphology

induces the formation of air pocket when the interaction with

the liquid is hydrophobic, otherwise it favourites the formation

of a precursor liquid film [44] that enhances the wettability of

the carbon nanotube surface, when the interaction with the

liquid is lipophilic.

Furthermore, we studied the stability of our carbon nanotube

films over time by performing suction experiments. Figure 5

reports the variations of the contact angle value as a function of

the elapsed time from dropping the liquid on the SWCNT,

MWCNT, SWCNT/MWCNT, and MWCNT/SWCNT coatings.

In such suction experiment, we show that although the samples

are porous, the contact angle trend is quite constant. In particu
lar, we demonstrated the stability over time of the hydrophobic

Cassie–Baxter metastable state for the SWCNT/MWCNT

sample. However, the slight linear decrease of the contact angle

in time is both due to liquid evaporation and suction by the

porous films. Our results are particularly remarkable, since the

water contact angle of carbon nanotube films has been reported

[45] so far to linearly decrease with time, from an initial value

of approx. 146° to about zero within 15 min.

## Conclusion

Single-walled and multi-walled carbon nanotube films were

prepared by vacuum filtration of an aqueous dispersion. Such

coatings were deposited by dry-transfer printing on glass, at

room temperature. Furthermore, SEM images revealed the

intrinsic hierarchical nature of carbon nanotube random

networks owed to a dry-induced out-of-plane self-assembly

phenomenon. Moreover, static contact angles of sessile water

drops cast on carbon nanotube composite surfaces were

measured, finding that our SWCNT random network films are

more hydrophobic than our MWCNT random network films.

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

Figure 5: Variations of the contact angle as a function of the elapsed
time from drop cast on the porous SWCNT (green triangles), MWCNT
(blue squares), SWCNT/MWCNT (orange inverted triangles), MWCNT/
SWCNT (red dots) films. The quite constant trend of the SWCNT/
MWCNT contact angle value shows the stability in time of the carbon
nanotube hydrophobic Cassie–Baxter metastable state.

This behavior may be ascribed to remarkable differences in the

two film morphology induced by our preparation method.

However, since the characteristic dimension of SWCNT is one

order of magnitude smaller than MWCNT, when a SWCNT

film is placed on a MWCNT film an extrinsic hierarchical

morphology occurs making the resulting composite surface

highly hydrophobic (θ = 129 ± 8°). We showed that our results

are due to two main reasons: (i) The characteristic dimension of

the self-assembly microstructures in the SWCNT/MWCNT

samples are comparable with those of micropapillae in

hydrophobic plant leaves. (ii) The hierarchical surface

morphology lead to the formation of a consistent amount of air

pockets, as a consequence of the transition from the

hydrophobic Wenzel state to the hydrophobic Cassie–Baxter

metastable state. In addition, we observed that the latter state is

fairly stable in time. Such highly hydrophobic hierarchical

carbon nanotube coatings may be very attracting for several

industrial applications such as waterproof surfaces [23], anti
sticking [31], anti-contamination [4], self-cleaning [46], anti
fouling [47], anti-fogging [48], low-friction coatings [5],

adsorption [30], lubrication [22], dispersion [44], and self
assembly [49].

## Experimental

Fabrication of carbon nanotube films

Highly pure SWCNT powder (Sigma-Aldrich, assay _>_ 90%,

diameter: 0.7–0.9 nm) and MWCNT powder (Nanocyl,

NC7000, assay _>_ 90%, diameter: 5–50 nm) were dispersed in
aqueous solution (80 μg·mL −1 ) with 2% w/v sodium dodecyl

sulfate (Sigma-Aldrich, assay _>_ 98.5%) anionic surfactant. In

addition, to better disperse the suspension, the carbon nanotubes

358

were tip-ultrasonicated (Branson S250A, 200 W, 20% power,

20 kHz) in an ice-bath for an hour and the unbundled super
natant was collected through a pipette. The result was a well
dispersed suspension that is stable for several months. Carbon

nanotube films were fabricated by a vacuum filtration process

of 1 mL in volume of the dispersion cast on mixed cellulose

ester filters (Pall GN6, 1 in diameter, 0.45 μm pore diameter).

In order to prepare hierarchical MWCNT/SWCNT films, after

filtering 1 mL of the SWCNT dispersion, 1 mL of the MWCNT

dispersion was filtered. This process was also carried out in

reverse order to produce SWCNT/MWCNT films. In this way,

a stack of two different film layers were obtained. Subse
quently, rinsing in water and in a solution of ethanol, methanol

and water (15:15:70) to remove as much surfactant as possible

was performed. Samples were made uniformly depositing by

the dry-transfer printing method carbon nanotube films on Carlo

Erba soda-lime glass slides. More details about this novel depo
sition technique without chemical deposition processes have

been reported elsewhere [41].

Sample characterization

Scanning electron microscopy micrographs were acquired with

Zeiss Leo Supra 35 field emission scanning electron micro
scope (FEG-SEM) and analyzed in order to measure carbon

nanotube bundle diameter, network pore, and microstructure

feature (height and area) distributions. A statistical analysis of

these quantities was performed and the values reported in

Table 1 were estimated by taking the quantity distribution mode

values and standard deviations. In particular, we performed

microstructure area measurements through analyzing the SEM

micrographs of the films at a magnification of 30,000× with a

threshold algorithm and considering their irregular shape. The

analysis of microstructure height was carried out on SEM

images acquired at a magnification of 10,000× at grazing angle,

i.e., by tilting the sample to an angle very close to 90° with

respect to the sample normal. In such a way, the height of film

microstructures can be estimated by trigonometric measure
ments. The film pore area defined as the area of the irregular

empty regions delimited by the intersection among carbon

nanotube bundles was quantified by the statistical analysis with

a threshold algorithm of film SEM images at the highest magni
fication (200,000×), at which pores are clearly observable. The

radius of the pore was calculated by considering the pore area

as that of a circle.

Contact angle measurements

Images of sessile water drops cast on carbon nanotube films

were acquired by a custom setup with a CCD camera. Static

advanced contact angles were measured by increasing the

volume of the drop by steps of 1 μL, and a plugin [50] for the

open-source software ImageJ was exploited to estimate the

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

contact angle values. This plugin exploits an algorithm based on

a small-perturbation solution of the Young–Laplace equation

[22]. Furthermore, the presented method is applied to a contin
uous image of the droplet by using cubic B-Spline interpolation

of the drop contour to reach subpixel resolution. Every contact

angle value reported is the average over five measures of

images of droplets cast on five different points of the film

(namely in the center, north, south, east, and west part). The

deionized water (18.2 MΩ·cm) drop volume used to achieve the

contact angles of samples was _V_ = 10 μL. Moreover, every

contact angle was measured 15 s after drop casting to ensure

that the droplet reached its equilibrium position.

## Acknowledgements

The authors thank R. De Angelis, F. De Matteis, and P.

Prosposito (Universitá di Roma Tor Vergata, Roma, Italy) for

their courtesy of contact angle instrumentation. This project was

financial supported by the European Office of Aerospace

Research and Development (EOARD) through the Air Force

Office of Scientific Research Material Command, USAF, under

Grant No. FA9550-14-1-0047.

## References

1. Wenzel, R. N. _Ind. Eng. Chem._ 1936, _28,_ 988–994.

[doi:10.1021/ie50320a024](http://dx.doi.org/10.1021%2Fie50320a024)

2. Feng, L.; Zhang, Y.; Xi, J.; Zhu, Y.; Wang, N.; Xia, F.; Jiang, L.

_Langmuir_ 2008, _24,_ [4114–4119. doi:10.1021/la703821h](http://dx.doi.org/10.1021%2Fla703821h)

3. Sun, M.; Luo, C.; Xu, L.; Ji, H.; Ouyang, Q.; Yu, D.; Chen, Y. _Langmuir_

2005, _21,_ [8978–8981. doi:10.1021/la050316q](http://dx.doi.org/10.1021%2Fla050316q)

4. Li, Y.; Huang, X. J.; Heo, S. H.; Li, C. C.; Choi, Y. K.; Cai, W. P.;

Cho, S. O. _Langmuir_ 2007, _23,_ [2169–2174. doi:10.1021/la0620758](http://dx.doi.org/10.1021%2Fla0620758)

5. Jung, Y. C.; Bhushan, B. _ACS Nano_ 2009, _3,_ 4155–4163.

[doi:10.1021/nn901509r](http://dx.doi.org/10.1021%2Fnn901509r)

6. Egatz-Gomez, A.; Majithia, R.; Levert, C.; Meissner, K. E. _RSC Adv._

2012, _2,_ [11472–11480. doi:10.1039/c2ra22267a](http://dx.doi.org/10.1039%2Fc2ra22267a)

7. Bittoun, E.; Marmur, A. _Langmuir_ 2012, _28,_ 13933–13942.

[doi:10.1021/la3029512](http://dx.doi.org/10.1021%2Fla3029512)

8. Shibuichi, S.; Onda, T.; Satoh, N.; Tsujii, K. _J. Phys. Chem._ 1996, _100,_

[19512–19517. doi:10.1021/jp9616728](http://dx.doi.org/10.1021%2Fjp9616728)

9. Cassie, A. B. D.; Baxter, S. _Trans. Faraday Soc._ 1944, _40,_ 546–551.

[doi:10.1039/tf9444000546](http://dx.doi.org/10.1039%2Ftf9444000546)

10.Bormashenko, E.; Bormashenko, Y.; Stein, T.; Whyman, G.;

Bormashenko, E. _J. Colloid Interface Sci._ 2007, _311,_ 212–216.

[doi:10.1016/j.jcis.2007.02.049](http://dx.doi.org/10.1016%2Fj.jcis.2007.02.049)

11.Gao, X.; Jiang, L. _Nature_ 2004, _432,_ [36. doi:10.1038/432036a](http://dx.doi.org/10.1038%2F432036a)

12.Lafuma, A.; Quéré, D. _Nat. Mater._ 2003, _2,_ 457–460.

[doi:10.1038/nmat924](http://dx.doi.org/10.1038%2Fnmat924)

13.Giacomello, A.; Chinappi, M.; Meloni, S.; Casciola, C. M.

_Phys. Rev. Lett._ 2012, _109,_ 226102.

[doi:10.1103/PhysRevLett.109.226102](http://dx.doi.org/10.1103%2FPhysRevLett.109.226102)

14.Giacomello, A.; Meloni, S.; Chinappi, M.; Casciola, C. M. _Langmuir_

2012, _28,_ [10764–10772. doi:10.1021/la3018453](http://dx.doi.org/10.1021%2Fla3018453)

15.Savoy, E. S.; Escobedo, F. A. _Langmuir_ 2012, _28,_ 16080–16090.

[doi:10.1021/la303407r](http://dx.doi.org/10.1021%2Fla303407r)

16.Murakami, D.; Jinnai, H.; Takahara, A. _Langmuir_ 2014, _30,_ 2061–2067.

[doi:10.1021/la4049067](http://dx.doi.org/10.1021%2Fla4049067)

359

17.Bico, J.; Thiele, U.; Quéré, D. _Colloids Surf., A_ 2002, _206,_ 41–46.

[doi:10.1016/S0927-7757(02)00061-4](http://dx.doi.org/10.1016%2FS0927-7757%2802%2900061-4)

18.Bhushan, B. _Philos. Trans. R. Soc. London, Ser. A_ 2009, _367,_

[1445–1486. doi:10.1098/rsta.2009.0011](http://dx.doi.org/10.1098%2Frsta.2009.0011)

19.Bar-Cohen, Y. _Biomimetics Biologically Inspired Technologies;_ CRC

Press: Boca Raton, 2005.

20.Iijima, S. _Nature_ 1991, _354,_ [56–58. doi:10.1038/354056a0](http://dx.doi.org/10.1038%2F354056a0)

21.Jorio, A.; Dresselhaus, G.; Dresselhaus, M. S. _Carbon Nanotubes_

_Advanced Topics in the Synthesis, Structure, Properties and_

_Applications;_ Springer: New York, 2008.

22.Adamson, A. W.; Gast, A. P. _Physical Chemistry of Surfaces;_ John

Wiley & Sons: New York, 1997.

23.Georgakilas, V.; Bourlinos, A. B.; Zboril, R.; Trapalis, C. _Chem. Mater._

2008, _20,_ [2884–2886. doi:10.1021/cm7034079](http://dx.doi.org/10.1021%2Fcm7034079)

24.Wang, N.; Xi, J.; Wang, S.; Liu, H.; Feng, L.; Jiang, L.

_J. Colloid Interface Sci._ 2008, _320,_ 365–368.

[doi:10.1016/j.jcis.2008.01.005](http://dx.doi.org/10.1016%2Fj.jcis.2008.01.005)

25.Yang, J.; Zhang, Z.; Men, X.; Xu, X.; Zhu, X. _J. Colloid Interface Sci._

2010, _346,_ [241–247. doi:10.1016/j.jcis.2010.02.040](http://dx.doi.org/10.1016%2Fj.jcis.2010.02.040)

26.Kakade, B. A.; Pillai, V. K. _J. Phys. Chem. C_ 2008, _112,_ 3183–3186.

[doi:10.1021/jp711657f](http://dx.doi.org/10.1021%2Fjp711657f)

27.Nasibulin, A. G.; Kaskela, A.; Mustonen, K.; Anisimov, A. S.; Ruiz, V.;

Kivistö, S.; Rackauskas, S.; Timmermans, M. Y.; Pudas, M.;

Aitchison, B.; Kauppinen, M.; Brown, D. P.; Okhotnikov, O. G.;

Kauppinen, E. I. _ACS Nano_ 2011, _5,_ 3214–3221.

[doi:10.1021/nn200338r](http://dx.doi.org/10.1021%2Fnn200338r)

28.Wang, C.-F.; Chen, W.-Y.; Cheng, H.-Z.; Fu, S.-L. _J. Phys. Chem. C_

2010, _114,_ [15607–15611. doi:10.1021/jp1047985](http://dx.doi.org/10.1021%2Fjp1047985)

29.Wang, K.; Hu, N.-X.; Xu, G.; Qi, Y. _Carbon_ 2011, _49,_ 1769–1774.

[doi:10.1016/j.carbon.2010.12.063](http://dx.doi.org/10.1016%2Fj.carbon.2010.12.063)

30.Li, J.; Wang, L.; Jiang, W. _Carbon_ 2010, _48,_ 2668–2671.

[doi:10.1016/j.carbon.2010.03.038](http://dx.doi.org/10.1016%2Fj.carbon.2010.03.038)

31.Wang, Z.; Koratkar, N.; Ci, L.; Ajayan, P. M. _Appl. Phys. Lett._ 2007, _90,_

[143117. doi:10.1063/1.2720761](http://dx.doi.org/10.1063%2F1.2720761)

32.Zhang, L.; Resasco, D. E. _Langmuir_ 2009, _25,_ 4792–4798.

[doi:10.1021/la8040264](http://dx.doi.org/10.1021%2Fla8040264)

33.Bu, I. Y. Y.; Oei, S. P. _Appl. Surf. Sci._ 2010, _256,_ 6699–6704.

[doi:10.1016/j.apsusc.2010.04.073](http://dx.doi.org/10.1016%2Fj.apsusc.2010.04.073)

34.Kakade, B.; Mehta, R.; Durge, A.; Kulkarni, S.; Pillai, V. _Nano Lett._

2008, _8,_ [2693–2696. doi:10.1021/nl801012r](http://dx.doi.org/10.1021%2Fnl801012r)

35.Li, S.; Li, H.; Wang, X.; Song, Y.; Liu, Y.; Jiang, L.; Zhu, D.

_J. Phys. Chem. B_ 2002, _106,_ [9274–9276. doi:10.1021/jp0209401](http://dx.doi.org/10.1021%2Fjp0209401)

36.Li, Q.; DePaula, R.; Zhang, X.; Zheng, L.; Arendt, P. N.; Mueller, F. M.;

Zhu, Y. T.; Tu, Y. _Nanotechnology_ 2006, _17,_ 4533–4536.

[doi:10.1088/0957-4484/17/18/001](http://dx.doi.org/10.1088%2F0957-4484%2F17%2F18%2F001)

37.Chakrapani, N.; Wei, B.; Carrillo, A.; Ajayan, P. M.; Kane, R. S.

_Proc. Natl. Acad. Sci. U. S. A._ 2004, _101,_ 4009–4012.

[doi:10.1073/pnas.0400734101](http://dx.doi.org/10.1073%2Fpnas.0400734101)

38.Bohn, S.; Platkiewicz, J.; Andreotti, B.; Adda-Bedia, M.; Couder, Y.

_Phys. Rev. E_ 2005, _71,_ [046215. doi:10.1103/PhysRevE.71.046215](http://dx.doi.org/10.1103%2FPhysRevE.71.046215)

39.Fusi, M.; Di Fonzo, F.; Casari, C. S.; Maccallini, E.; Caruso, T.;

Agostino, R. G.; Bottani, C. E.; Bassi, A. L. _Langmuir_ 2011, _27,_

[1935–1941. doi:10.1021/la103955q](http://dx.doi.org/10.1021%2Fla103955q)

40.Sauvage, F.; Di Fonzo, F.; Li Bassi, A.; Casari, C. S.; Russo, V.;

Divitini, G.; Ducati, C.; Bottani, C. E.; Comte, P.; Graetzel, M.

_Nano Lett._ 2010, _10,_ [2562–2567. doi:10.1021/nl101198b](http://dx.doi.org/10.1021%2Fnl101198b)

41.De Nicola, F.; Castrucci, P.; Scarselli, M.; Nanni, F.; Cacciotti, I.;

De Crescenzi, M. _Sci. Rep._ 2014, in press.

42.Clark, M. D.; Krishnamoorti, R. _Thin Solid Films_ 2012, _520,_ 4332–4338.

[doi:10.1016/j.tsf.2012.02.067](http://dx.doi.org/10.1016%2Fj.tsf.2012.02.067)

_Beilstein J. Nanotechnol._ 2015, _6,_ 353–360.

43.Quéré, D. _Nat. Mater._ 2002, _1,_ [14–15. doi:10.1038/nmat715](http://dx.doi.org/10.1038%2Fnmat715)

44.De Gennes, P.-G.; Brochard-Wyart, F.; Quéré, D. _Capillarity and_

_wetting phenomena;_ Springer: New York, 2003.

45.Huang, L.; Lau, S. P.; Yang, H. Y.; Leong, E. S. P.; Yu, S. F.

_J. Phys. Chem. B_ 2005, _109,_ [7746–7748. doi:10.1021/jp046549s](http://dx.doi.org/10.1021%2Fjp046549s)

46.Fürstner, R.; Barthlott, W.; Neinhuis, C.; Walzel, P. _Langmuir_ 2005, _21,_

[956–961. doi:10.1021/la0401011](http://dx.doi.org/10.1021%2Fla0401011)

47.Zhang, H.; Lamb, R.; Lewis, J. _Sci. Technol. Adv. Mater._ 2005, _6,_

[236–239. doi:10.1016/j.stam.2005.03.003](http://dx.doi.org/10.1016%2Fj.stam.2005.03.003)

48.Lai, Y.; Tang, Y.; Gong, J.; Gong, D.; Chi, L.; Lin, C.; Chen, Z.

_J. Mater. Chem._ 2012, _22,_ [7420–7426. doi:10.1039/c2jm16298a](http://dx.doi.org/10.1039%2Fc2jm16298a)

49.Huang, Y.; Zhou, J.; Su, B.; Shi, L.; Wang, J.; Chen, S.; Wang, L.;

Zi, J.; Song, Y.; Jiang, L. _J. Am. Chem. Soc._ 2012, _134,_ 17053–17058.

[doi:10.1021/ja304751k](http://dx.doi.org/10.1021%2Fja304751k)

50.Stalder, A. F.; Melchior, T.; Müller, M.; Sage, D.; Blu, T.; Unser, M.

_Colloids Surf., A_ 2010, _364,_ [72–81. doi:10.1016/j.colsurfa.2010.04.040](http://dx.doi.org/10.1016%2Fj.colsurfa.2010.04.040)

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