Article pubs.acs.org/JPCC
Mechanically Induced Self-Healing Superhydrophobicity Yanhua Liu,†,‡ Yupeng Liu,† Haiyuan Hu,† Zhilu Liu,*,† Xiaowei Pei,*,† Bo Yu,*,† Pengxun Yan,†,‡ and Feng Zhou† †
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China ‡ School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China S Supporting Information *
ABSTRACT: The design of materials with self-healing hydrophobicity induced by stimuli such as temperature, humidity, and pH has raised considerable interest because of the high practical potential of such materials. Mechanically induced self-healing superhydrophobicity was realized by facilely coating textiles with polydopamine (PDA) nanocapsule-encapsulated hydrophobic agents such as octadecylamine (ODA) and octadecanethiol (ODT). The polydopamine nanocapsules with hydrophobic agents trapped inside endow the textiles with hydrophobicity and fast self-healing ability; once hydrophobicity is lost because of damage to surface chemistry, hydrophobic agents are released with multiple mechanical stimuli including stretching, compression, friction, and even mechanical washing. Compared with stimuli including temperature, humidity, and pH, mechanical stimuli are easy to apply and more compatible with daily life, making the present hydrophobic textiles with rapid self-healing performance promising materials for practical and technological applications.
1. INTRODUCTION One shortcoming of textiles is that they are easily stained. To overcome this disadvantage, hydrophobization modification of textiles to enable anticontamination and self-cleaning has attracted increasing attention.1−3 However, application of these textiles in practice is limited because of low durability because their surfaces are generally in the metastable state and the surface structure and chemistry are liable to mechanical damage.4−7 One solution to solve the problem is biomimetic self-healing.8,9 Inspired by nature, self-healing surfaces with long-term wetting stability by gradual release of hydrophobic small molecules stored in nanoporous surfaces or nanocapsulecoated fabrics have been achieved.8−14 In this work, different stimuli such as temperature, humidity, and pH changes were employed to induce the release of hydrophobic molecules. However, the self-healing induced by these physical and chemical factors usually requires a long time; moreover, all the treatments are not simple enough for the self-healing process to be completed in daily life application. Therefore, it is still desirable to develop durable hydrophobic surfaces with a self-healing ability under easier and natural stimuli, such as mechanical strain. Mechanical strain is ubiquitous in body movement or very simple to apply externally. Thus, self-healing hydrophobicity induced by mechanical forces like stretch, compression, and friction, if possible, could be applied in patches of textiles that respond to body motions. Moreover, because mechanical washing, which applies mechanical forces © 2015 American Chemical Society
too, is unavoidable for clothing once contaminated, mechanical force-induced self-healing hydrophobic textiles, if compatible with mechanical washing, are beyond all doubt desirable for daily life. To date, to the best of our knowledge, mechanical force has been successfully used to induce the release of drug molecules, while stimulating release of hydrophobic agents to realize self-healable hydrophobicity has not been reported.15−18 According to a previous report by You et al, superhydrophobic surfaces can be prepared on any type of material surface using mussel-inspired polydopamine (PDA), in which PDA plays a critical role in material-independent superhydrophobic materials. Moreover, this kind of superhydrophobic surface presents enhanced mechanical stability.19 Hence, PDA can be used as a mediator to prepare robust superhydrophobic textiles. Herein, we describe a simple approach for preparing a self-healing hydrophobic surface induced by mechanical forces such as stretching, compression, friction, and mechanical washing. Polydopamine nanocapsule-encapsulated hydrophobic agents, polydopamine@octadecylamine (PDA@ODA) or polydopamine@octadecanethiol (PDA@ ODT), were used to modify textiles. They were spontaneously deposited from a microemulsion of octadecylamine or octadecanethiol and dopamine onto textiles with high adhesion Received: December 3, 2014 Revised: March 4, 2015 Published: March 20, 2015 7109
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
Article
The Journal of Physical Chemistry C
angle meter (Kruss Co., Ltd., Germany) at ambient temperature. A 5 μL amount of deionized water was dropped onto the samples using an automatic dispense controller, and the CAs were determined automatically using the Laplace−Young fitting algorithm. Average CA values were obtained by measuring the sample at five different positions, and images were captured with a digital camera (Sony, Ltd., Japan). SEM images were obtained on a JSM-6701F field emission scanning electron microscope (FE-SEM, Japan) at 5−10 kV, and TEM images were obtained on a FEI Tecnai G2 F30 transmission electronic microscope. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy was performed to investigate the characteristics of the specimens on a Nicolet iS10 instrument (Thermo Scientific). All the photos and videos were taken using a Canon camera.
strength and provided roughness to complement the microscale roughness inherent in the fabric weaves for hydrophobicity. When the coated surface is damaged and loses its liquid repellency because of hydrophobic molecules, ODA or ODT can migrate to the surface with the help of mechanical stimuli including stretching, compression, and friction and restore the fabric’s hydrophobicity rapidly. Remarkably, the coated fabric displays an excellent self-healing hydrophobicity with mechanical washing. Hydrophobic textiles with rapid self-healing performance under easy and natural mechanical stimuli are believed to be promising for practical and technological applications.
2. MATERIALS AND METHODS 2.1. Materials. Dopamine was purchased from Acros Organic. Octadecanethiol (ODT), octadecylamine (ODA), and tris (hydroxymethyl) aminomethane (Tris) were obtained from Shanghai Chemical Regent Co. Textiles was commercially available polyester fabric and cotton fabric. 2.2. Methods. A previously reported method was employed to prepare textiles coated with PDA@ODA or PDA@ODT nanocapsules.14 Typically, ODA or ODT was first added in deionized water by supersonic stirring to form a white emulsion. Then, the formed emulsion was dispersed in TrisHCl (pH 8.5) buffer with 0.5 mg/mL dopamine and a piece of clean elastic cord was soaked in the as-prepared mixture for 24 h at ambient temperature. Finally, the resulting brown elastic was washed with ethanol and deionized water to remove the residuals and then dried at room temperature for 12 h. Similarly, the sponge coated with PDA@ODT and the cotton fabric and glove coated with PDA@ODA were prepared separately using the same method as described above. 2.3. Plasma Treatment. The samples were subjected to 20 s of oxygen plasma treatment using a plasma machine (Diener Electronic, Germany) to simulate the surface chemistry damage. Such a plasma treatment can make the sample completely hydrophilic (contact angle, 0°). The plasma-treated samples were then carried out by stretching, compression, and friction tests at ambient temperature. 2.4. Dye Method. To make the fabric and glove modified with PDA@ODA nanocapsules more attractive, they were dyed blue. The coated cotton fabric was treated using oxygen plasma and then dipped in dyebaths (1% methylene blue solution) for 10 min. The unfixed dye was removed by water rinsing, and then the dyed fabric was dried in oven at 80 °C for 20 min. 2.5. General Procedure for Stretch Studies. The elastic cord coated with PDA@ODT was treated with plasma at first and then loaded into a tensile−compression tester (EZ-Test, Shimadzu, Japan) at a deformation rate of 500 mm/min using different stretching rates. Then, the contact angle was measured again after 500 stretching cycles. 2.6. General Procedure for Compression Studies. The sponge coated with PDA@ODT was treated with plasma at first and then loaded into a tensile−compression tester (EZTest, Shimadzu, Japan) at a deformation rate of 500 mm/min in air. Then, the contact angle was measured again after 50 compression cycles. 2.7. General Procedure for Friction Studies. The cotton fabric coated with PDA@ODA was treated with plasma at first and then was rubbed with hands for 1 min. Then contact angle was measured once again. 2.8. Characterization. Sessile water-droplet contact angle (CA) values were acquired using a DSA-100 optical contact-
3. RESULTS AND DISCUSSION Mechanical force-induced self-healing is expected to be of interest because of its practical advantages. A macroscopic stretch, compression, or even friction is a simple stimulus from a technical point of view to realize the self-healing of hydrophobicity on a fabric surface. In the present study, we used polydopamine with good surface-adherent ability as nanocapsules to a reserve hydrophobic agent such as octadecylamine (ODA) and coated PDA@ODA nanocapsules on textiles through a facile in situ polymerization method. As illustrated in Scheme 1a, the textile coated with PDA@ODA Scheme 1. Schematic Illustration of (a) Regeneration of Hydrophobicity through Mechanical Stimulation and (B) Mechanism in the Self-Healing Process during Compression
nanocapsules was destroyed by plasma treatment using oxygen. After the treatment, alkyl chains on the surface were removed and the treated surface became hydrophilic. However, when the textile treated by plasma was stretched, compressed, or rubbed using mechanical force, hydrophobic molecules would release from PDA reservoirs, as shown in Scheme 1b, and finally the liquid repellency of the treated textile was restored. 3.1. Stretching Force-Induced Self-Healing Hydrophobicity on Elastic Textiles. Figure 1 provides morphological information on elastic cord coated with PDA@ODT capsules. Without coating, the elastic cord showed a smooth surface (Figure 1a,b), while the coated elastic cord became much rougher (Figure 1c,d), which provides roughness at the nanoscale to compliment the microscale roughness inherent in the fiber of the elastic cord. To check if stretching force applied on the elastic cord coated with PDA@ODT capsules can trigger the release of ODT from PDA capsules and realize the self-healing of hydrophobicity, the coated elastic cord was treated by O2 plasma and then stretched by a tensile−compression tester, as shown in Figure S1 in Supporting Information. Figure 2a 7110
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
Article
The Journal of Physical Chemistry C
while the peak intensity of the ester group was reduced inversely. This result indicates that alkyl chains were detached from the coated layer by plasma treatment but reintroduced because of the stretching, leading to release of ODT molecules from the capsules. Importantly, upon repeated stretching, the rough surface formed with PDA@ODT nanocapsules maintained the initial structure without any cracks or peeling, as illustrated in Figure 2c,d, revealing its excellent robustness. The insert in Figure 2c verifies that the particle coated on the fabric is a capsule. To investigate the effect of stretch rate α, the ratio of stretched length to the original length of elastic cord, on the self-healing of hydrophobicity, evolution of water contact angle with stretching cycles under stretching rates α ranging between 0 and 100% was studied (Figure 3). As shown in Figure 3a, for Figure 1. SEM images of (a,b) uncoated and (c,d) PDA@ODT nanocapsule-coated elastic cord. Scale bars: 50 μm (a,c) and 5 μm (b,d).
Figure 3. (a) Evolution of water contact angle with stretching cycles under different stretch rates. Several stretch rates α were applied on the samples: from α = 0 to α = 100%. CA was measured after every 500 cycles of the cyclic tensile test. (b) Plot of the recovery of contact angle obtained after first 500 cycles of tensile test versus stretch rate.
the control sample, α = 0, the contact angle reached only 100° even after 2 days without stretching just because of the diffusion of trapped ODT, while the contact angle under stretching force (α = 20%, 40%, 60%, 80%, 100%) can recover rapidly, and the higher the α value, the faster the recovery. For α = 100%, the contact angle reached to about 150° after 2500 stretching cycles, illustrating that the destroyed surface has been recovered completely. Figure 3b shows the plot of contact angle after the first 500 stretching cycles with different stretching rates from 0 to 100%, which further illustrates that the higher the stretching rate, the bigger the contact angle, indicating that the self-healing of hydrophobicity is highly dependent on the stretching rate. The plot also demonstrates that the self-healing ability of the modified elastic cord increases with the stretching rate, which may result from the fast release of ODT molecules due to the more serious deformation of PDA nanocapsules under higher strain.22 3.2. Compression Force-Induced Self-Healing Hydrophobicity on a Sponge. To investigate the effects of load history on the self-healing ability, the PDA@ODT-coated sponge was employed because of its good compressibility. As observed by the SEM images in Figure 4a,b, the surface of the PDA@ODT-coated sponge is rough, resulting in the superhydrophobicity, with water contact angle of about 152°. However, after 20 s of oxygen plasma treatment, the superhydrophobicity of the PDA@ODT-coated sponge was lost and the water contact angle decreased to about 90°. However, when the sponge treated by plasma was compressed with compression tester 250 times (Figure 4c), its liquid repellency was restored (Figure S2a in Supporting Information). Similar to the PDA@ODT-coated elastic cord subjected to stretch tests, the intensity of FTIR characteristic peaks at
Figure 2. (a) Variation of contact angle with stretch times; (b) FTIR spectra of elastic cord coated with PDA@ODT nanocapsules, treated with plasma and stretching; SEM images of the coated sponge before (c) and after (d) stretch treatment. The inset in panel c shows a TEM image of PDA@ODT nanocapsule. Scale bars: 1 μm (c, d); 200 nm (the inset in panel c).
indicates the plot of contact angle variation with stretching times. After O2 plasma treatment, the water contact angle changed from 150° to 0°. With the increase of stretching cycles, the contact angle increased rapidly. After experiencing 2500 stretching cycles, the contact angle has been recovered completely. The chemical components of the coating layer were verified by FTIR, as illustrated in Figure 2b. After the cord was modified with PDA@ODT nanocapsules, the vibration peaks appearing at 2917 and 2856 cm−1 were attributed to C− H stretching vibrations of methylene and the peak at 720 cm−1 was attributed to the rocking vibration of −CH2−;20 the vibration peak appearing at 1718 cm−1 was attributed to −C O stretching vibrations of tautomer in PDA.21 FTIR results confirm that the elastic cord was covered with PDA@ODT nanocapsules with alkyl chain on the surface. After plasma treatment, the intensity of peaks at 2917 and 2856 cm−1 and that at 720 cm−1 decreased while the intensity of the peak at −CO of tautomer in PDA increased. After the cord was stretched 2500 times, the intensity of these peaks increased 7111
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
Article
The Journal of Physical Chemistry C
Figure S3a and Movie 1 in Supporting Information. The chemical components characterized by FTIR also verified the healed hydrophobic surface, as shown in Figure S3b in Supporting Information. Importantly, this feasible frictioninduced self-healing ability was repeatable. As shown in Figure 5d, 10 repetitions of the switching of water contact angle were achieved with plasma and rubbing treatment in turn. Note that 10 repetitions of plasma and rubbing treatment in turn resulted in the fiber surface becoming a bit rougher, whereas the microand nanoscale hierarchical structures remained and the nanocapsules coated on the fiber were still dense and uniform (Figure 5e,f). 3.4. Demonstration of Mechanical Force-Induced SelfHealing Hydrophobicity on Textiles. The glove coated with PDA@ODA nanocapsules was investigated as practical application using the concept of strain-responsive self-healing of hydrophobicity, as demonstrated in Figure 6. To
Figure 4. SEM images of (a) uncoated and (b) PDA@ODT-coated sponge. (c) Variation of contact angle with compression times. The inserts are pictures of water droplets on the compressed sponge. SEM images of the coated sponge before (d) and after (e) compress treatment. Scale bars: 5 μm (a,b); 2 μm (d,e).
2922, 2853, and 720 cm−1 (Figure S2b in Supporting Information) for the PDA@ODT-coated sponge decreased and then increased after the plasma treatment and compression test, respectively. It is also found that the high robustness of the PDA@ODT nanocapsule-coated sponge guaranteed the dense and uniform nanocapsule coating remained unchanged after compression healing tests (Figure 4d,e). The rapid self-healing hydrophobicity and excellent robustness under mechanical strain implies the PDA@ODT-coated textiles have high potential for practical applications. However, because of the smell of PDA@ODT, they are suitable for industry but might be unacceptable for daily life; thus, the nontoxic and odorless PDA@ODA nanocapsules were tested to investigate the feasibility of the method for self-healing hydrophobic clothing. 3.3. Friction-Induced Self-Healing Hydrophobicity on Cotton Textiles. Because cotton fabric is popular, PDA@ ODA nanocapsules were coated on cotton fabric to investigate the self-healing ability of superhydrophobicity. It exhibited rough structure, as shown in Figure 5a,b. For clothing, a gentle
Figure 6. (a) Wettability of glove modified with PDA@ODA nanocapsules after plasma treatment; (b) self-healing of hydrophobicity induced by mechanical force applied by opening and closing hand.
demonstrate the self-healing phenomenon directly, the PDA@ODA nanocapsule-coated glove was treated using plasma, and it became hydrophilic (Figure 6a). Figure 6b shows how the glove coated with PDA@ODA nanocapsules can be used as a strain-regulated self-healing model: the motion of gripping and stretching induced self-healing of hydrophobicity. In daily life, textiles with water repellence would be damaged occasionally, and then the destroyed part would be stained; thus, washing is inevitable. The reparable hydrophobicity of textiles with mechanical washing will be fantastic and significant. Inspired by friction-induced self-healing of water repellency, a mechanical washing process was applied to the PDA@ODA nanocapsule-coated cotton fabric to verify the feasibility, as showed in Figure 7. Initially, the PDA@ODA nanocapsule-coated cotton fabric had good hydrophobicity with milk droplets standing in perfect spheres, as demonstrated in Figure 7a. When the coated fabric was exposed to O2 plasma, it became hydrophilic and was contaminated easily by milk droplets (Figure 7b). In order to remove the contamination, the stained fabric was washed by hands rubbing in water, as showed in Figure 7c. After being rubbed for 5 min, the fabric was dried in the air at room temperature. It was found that the
Figure 5. SEM images of (a) uncoated and (b) PDA@ODA-coated cotton fabric; (c) friction healing test with hands; (d) contact angles of water on the coated fabric in the ten cycles of plasma and friction treatment; SEM images of the coated fabric before (e) and after (f) 10 cycles of plasma and friction. Scale bars: 5 μm (a,b), 2 μm (e,f).
rubbing or washing is desirable, rather than stretching or compressing. Therefore, friction-induced hydrophobicity selfhealing is quite important for clothing with a water-proof property. As was done previously, the PDA@ODA-coated cotton fabric was treated using oxygen plasma, which became hydrophilic with a contact angle of 0° to water. However, when the hydrophilic fabric was rubbed with hands for only 1 min (Figure 5c), its liquid-repellency was restored, as shown in 7112
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
Article
The Journal of Physical Chemistry C Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS This research project was financially supported by the National Natural Science Foundation of China (21303233, 51203173, 51403220).
■
(1) Leng, B.; Shao, Z.; de With, G.; Ming, W. Superoleophobic cotton textiles. Langmuir 2009, 25, 2456−2460. (2) Vasiljevic, J.; Gorjanc, M.; Tomsic, B.; Orel, B.; Jerman, I.; Mozetic, M.; Vesel, A.; Simoncic, B. The surface modification of cellulose fibres to create super-hydrophobic, oleophobic and selfcleaning properties. Cellulose (Dordrecht, Neth.) 2013, 20, 277−289. (3) Shillingford, C.; MacCallum, N.; Wong, T. S.; Kim, P.; Aizenberg, J. Fabrics coated with lubricated nanostructures display robust omniphobicity. Nanotechnology 2014, 25, 014019. (4) Xue, C. H.; Ma, J. Z. Long-lived superhydrophobic surfaces. J. Mater. Chem. A 2013, 1, 4146−4161. (5) Jin, H.; Tian, X.; Ikkala, O.; Ras, R. H. A. Preservation of superhydrophobic and superoleophobic properties upon wear damage. ACS Appl. Mater. Interfaces 2013, 5, 485−488. (6) Zhu, X.; Zhang, Z.; Yang, J.; Xu, X.; Men, X.; Zhou, X. Facile fabrication of a superhydrophobic fabric with mechanical stability and easy-repairability. J. Colloid Interface Sci. 2012, 380, 182−186. (7) Verho, T.; Bower, C.; Andrew, P.; Franssila, S.; Ikkala, O.; Ras, R. H. A. Mechanically durable superhydrophobic surfaces. Adv. Mater. (Weinheim, Ger.) 2011, 23, 673−678. (8) Li, Y.; Li, L.; Sun, J. Bioinspired self-healing superhydrophobic coatings. Angew. Chem, Int. Ed. 2010, 49, 6129−6133. (9) Wang, X.; Zhou, F.; Liu, W. Self-healing superamphiphobicity. Chem. Commun. (Cambridge, U.K.) 2011, 47, 2324−2326. (10) Wang, H.; Xue, Y.; Ding, J.; Feng, L.; Wang, X.; Lin, T. Durable, self-healing superhydrophobic and superoleophobic surfaces from fluorinated-decyl polyhedral oligomeric silsesquioxane and hydrolyzed fluorinated alkyl silane. Angew. Chem., Int. Ed. 2011, 50, 11433−11436. (11) Zhou, H.; Wang, H.; Niu, H.; Gestos, A.; Wang, X.; Lin, T. Fluoroalkyl silane modified silicone rubber/nanoparticle composite: A super durable, robust superhydrophobic fabric coating. Adv. Mater. (Weinheim, Ger.) 2012, 24, 2409−2412. (12) Wang, H.; Zhou, H.; Gestos, A.; Fang, J.; Niu, H.; Ding, J.; Lin, T. Robust, electro-conductive, self-healing superamphiphobic fabric prepared by one-step vapour-phase polymerisation of poly(3,4ethylenedioxythiophene) in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane and fluorinated alkyl silane. Soft Matter 2013, 9, 277−282. (13) Wong, T. S.; Kang, S. H.; Tang, S. K. Y.; Smythe, E. J.; Hatton, B. D.; Grinthal, A.; Aizenberg, J. Bioinspired self-repairing slippery surfaces with pressure-stable omniphobicity. Nature 2011, 477, 443− 447. (14) Liu, Y.; Liu, Z.; Liu, Y.; Hu, H.; Li, Y.; Yan, P.; Yu, B.; Zhou, F. One-step modification of fabrics with bioinspired polydopamine@ octadecylamine nanocapsules for robust and healable self-cleaning performance. Small 2015, 11, 426−431. (15) Hu, J.; Liu, S. Responsive polymers for detection and sensing applications: Current status and future developments. Macromolecules 2010, 43, 8315−8330. (16) Hyun, D. C.; Moon, G. D.; Park, C. J.; Kim, B. S.; Xia, Y.; Jeong, U. Strain-controlled release of molecules from arrayed microcapsules supported on an elastomer substrate. Angew. Chem., Int. Ed. 2011, 50, 724−727. (17) Vogt, C.; Mertz, D.; Benmlih, K.; Hemmerle, J.; Voegel, J. C.; Schaaf, P.; Lavalle, P. Layer-by-layer enzymatic platform for stretchedinduced reactive release. ACS Macro Lett. 2012, 1, 797−801. (18) Barthes, J.; Mertz, D.; Bach, C.; Metz-Boutigue, M. H.; Senger, B.; Voegel, J. C.; Schaaf, P.; Lavalle, P. Stretch-induced biodegradation
Figure 7. Demonstration of self-healable hydrophobicity induced by mechanical washing. Photos of milk droplets on cotton fabric (a) coated with PDA@ODA and (b) after plasma treatment, (c) mechanical washing of fabric stained with milk, (d) milk droplets on fabric with healed hydrophobicity induced by mechanical washing.
milk droplets dropped on the surface formed round balls again with a contact angle of about 151°, as demonstrated in Figure 7d, revealing the recovery of superhydrophobicity. Briefly, mechanical washing process can not only be used to remove contamination stained on textiles but also be utilized for the self-healing hydrophobicity of textiles.
4. CONCLUSIONS We demonstrated mechanical force-induced self-healing hydrophobicity on textiles. Polydopamine nanocapsules with trapped hydrophobic agents such as octadecanethiol and octadecylamine inside were coated on textiles via in situ polymerization, which were found to have responses to mechanical force including stretching, compression, friction, and even mechanical washing by triggering the release of hydrophobic molecules and subsequently the healing of water repellency. This strategy was successfully applied for the self-healing hydrophobicity induced by mechanical stimuli and daily mechanical washing process, thereby demonstrating its potential application in the field of mechanical stimuli-responsive hydrophobic fabrics.
■
ASSOCIATED CONTENT
S Supporting Information *
Stretching reparability test using tensile−compression tester (Figure S1); photograph of water droplets on PDA@ODT nanocapsule-coated sponge after compression test and FTIR spectra of sponge coated with PDA@ODT nanocapsules treated with plasma and repeat compression (Figure S2); photograph of water droplets on PDA@ODA nanocapsulecoated fabric after friction test and FTIR spectra of fabric coated with PDA@ODA nanocapsules, treated with plasma and friction (Figure S3); video of self-healing superhydrophobicity of cotton fabric using rubbing with hands. This material is available free of charge via the Internet at http://pubs.acs.org.
■
REFERENCES
AUTHOR INFORMATION
Corresponding Author
*18 Middle Tianshui Road, Lanzhou 730000, China. Tel: +860931-4968508. E-mail:
[email protected]. 7113
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
Article
The Journal of Physical Chemistry C of polyelectrolyte multilayer films for drug release. Langmuir 2012, 28, 13550−13554. (19) You, I.; Seo, Y. C.; Lee, H. Material-independent fabrication of superhydrophobic surfaces by mussel-inspired polydopamine. RSC Adv. 2014, 4, 10330−10333. (20) Zhou, H.; Wang, H.; Niu, H.; Lin, T. Superphobicity/philicity janus fabrics with switchable, spontaneous, directional transport ability to water and oil fluids. Sci. Rep. 2013, 3, 2964. (21) Ma, S.; Liu, J.; Ye, Q.; Wang, D.; Liang, Y.; Zhou, F. A general approach for construction of asymmetric modification membranes for gated flow nanochannels. J. Mater. Chem. A 2014, 2, 8804−8814. (22) Fernandes, P. A. L.; Delcea, M.; Skirtach, A. G.; Möhwalda, H.; Fery, A. Quantification of release from microcapsules upon mechanical deformation with AFM. Soft Matter 2010, 6, 1879−1883.
7114
DOI: 10.1021/jp5120493 J. Phys. Chem. C 2015, 119, 7109−7114
