Fabrication of superhydrophobic and antibacterial surface on cotton fabric by doped silica- based sols with nanoparticles of copper
© Berendjchi et al; licensee Springer. 2011
Received: 13 May 2011
Accepted: 15 November 2011
Published: 15 November 2011
The study discussed the synthesis of silica sol using the sol-gel method, doped with two different amounts of Cu nanoparticles. Cotton fabric samples were impregnated by the prepared sols and then dried and cured. To block hydroxyl groups, some samples were also treated with hexadecyltrimethoxysilane. The average particle size of colloidal silica nanoparticles were measured by the particle size analyzer. The morphology, roughness, and hydrophobic properties of the surface fabricated on cotton samples were analyzed and compared via the scanning electron microscopy, the transmission electron microscopy, the scanning probe microscopy, with static water contact angle (SWC), and water shedding angle measurements. Furthermore, the antibacterial efficiency of samples was quantitatively evaluated using AATCC 100 method. The addition of 0.5% (wt/wt) Cu into silica sol caused the silica nanoparticles to agglomerate in more grape-like clusters on cotton fabrics. Such fabricated surface revealed the highest value of SWC (155° for a 10-μl droplet) due to air trapping capability of its inclined structure. However, the presence of higher amounts of Cu nanoparticles (2% wt/wt) in silica sol resulted in the most slippery smooth surface on cotton fabrics. All fabricated surfaces containing Cu nanoparticles showed the perfect antibacterial activity against both of gram-negative and gram-positive bacteria.
Keywordscotton superhydrophobicity antibacterial sol-gel method contact angle
Studying over 200 species of water repellent plants, Neinhuis and Barthlott  found an ideally wonderful superhydrophobic effect on lotus (Nelumbo nucifera) leaves which leads to supreme self-cleaning properties, so-called lotus effect [2, 3]. The rough structure of lotus leaves (hills and valleys template) causes a reduced contact area with water. The presence of the hydrophobic nanoparticles, however, will prevent water from penetrating hills .
To simulate or produce such superhydrophobic surface on substrates, among different methods ( such as chemical vapor deposition , phase inversion , electrospinning , electrowetting , lithography , and etching ), the sol-gel method seems more conventional to be used on textile materials, due to easy processing and acceptable treatment conditions (e.g., low temperature) [11–17]. In this method, hydrolysis and condensation reactions of the precursor material are carried out to form a nano-colloidal solution, and a network of nanoparticles will be formed on the substrate through the gradual evaporation of the solvent. The precursors are often based on metal organic compounds such as acetylacetonate, or metal alkoxides like tetraethoxysilane Si(OC2H5)4 (TEOS), titanium(IV) isopropoxide Ti(OC3H7)4, and Al(OC4H9)3.
According to its natural properties, cotton fabric is among the very popular textiles. Producing superhydrophobic surface on cotton fabric will guarantee its dryness and cleanness which are considered as desired features, in particular on its outside facet [11–17, 19–21]. Furthermore, cotton fabric is an ideal place for settling and growing pathogenic bacteria because of its porous and hydrophilic structure. So, antibacterial finishing is also of importance, especially in some specific applications like medical usage. There are many antibacterial agents used in this field, including metal nanoparticles like silver and copper [22–29]. The latter is the most familiar antibacterial agent used for centuries. Like many other particles, the desired properties of copper may be improved by reducing its size to nano-scale. Hence, these nanoparticles can be developed and applied in various new fields, such as water purification, medical science, human tissue, antifouling and antibacterial agent, etc. .
Few researches have been focused on developing two abovementioned properties on cellulosic substrates like cotton fabric, simultaneously [30–32]. On the other hand, nanoparticles of copper and core shell SiO2/Cu have been less developed for textile finishing [33–36]. The current aimed to fabricate an antibacterial and superhydrophobic surface on the cotton fabric, by introducing Cu nanoparticles into the silica sols. It was expected that due to their chemical activities, such nanoparticles would change the morphology and arrangement of silica nanostructure, and in addition, promote antibacterial activity on cotton fabrics.
Bleached and desized cotton fabric was provided by Polpine Co (Iran, Rasht). Tetraethylorthosilicate (TEOS), hydroxide ammonium (NH4OH 25%) and ethanol (C2H5OH 98%) were purchased from Merck Company. Nano-Cu (average particle size, 40 ±5 nm) was obtained from Plasma Company (PlasmaChem GmbH, Berlin, Germany), and hexadecyltrimethoxysilane (HDTMS) was purchased from Fluka Company (Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany). All chemicals were used as received without any further purification.
Colloidal SiO2 nanoparticle solutions were prepared considering the principles of Stöber method: 25 ml of ethanol, 1 ml of ammonium hydroxide, 3.6 ml of distilled water, and 11.5 ml of TEOS were mixed for 2 h at room temperature .
The prepared silica sols doped with two different amounts (0.5% and 2.0% wt/wt) of Cu nanoparticles, and were then sonicated for 30 min. Cotton fabric samples were immersed in the sols at 30°C for 5 min, dried for 24 h at ambient temperature and cured at 160°C for 5 min, respectively. Some samples were immersed in hydrolyzed and diluted HDTMS (with 4% wt/wt ethanol) for 4 h at room temperature. Again, these samples were cured at 120°C for 1 h .
Particle sizes of the silica sols prepared were measured with a particle size analyzer (Malvern Instruments, Malvern, Worcestershire, UK). The surface morphology was investigated by the scanning electron microscope (SEM) (XL30, Philips, Royal Philips Electronics, Amsterdam, Netherlands), while the surface roughness was analyzed via the scanning probe microscope (SPM) (DualScope™ C26, DME, Herlev, Denmark) using AC mode. The SiO2/Cu hybrid structure was observed with the transmission electron microscope (TEM) (EM 10C, Zeiss, Oberkochen, Germany). The static water contact angle (SWC) was determined by using a contact angle measurement device (Krüss G10, KRÜSS GmbH, Hamburg, Germany). At 23 ± 5°C, a 10-μl droplet of deionized water was placed into five different positions on the sample surfaces, and the angles of drops on the fabrics were determined. The static contact angle values for the sample reported were the average of five measurements.
Water shedding angle (WSA) of various samples was measured by the method of Zimmermann et al. . After releasing a drop of water (15 μl) in a height of 1 cm, the minimum angle of inclination at which the drop completely rolls off the surface was determined.
The antibacterial activity of samples was quantitatively evaluated using AATCC 100 method. Two non-spore-forming bacteria, one Gram-positive Staphylococcus aureus (ATCC = 25923) and one Gram-negative Escherichia coli (ATCC = 25922), were used for antibacterial testing.
For determining the number of bacteria after 0 contact time, autoclaved swatches were placed in wide mouth glass jars and 100 μl of inoculums (containing 106 colony-forming units (CFU) was poured on each of them. Immediately after inoculation ("0" contact time), 100 ml of neutralizing solution (phosphate-buffered saline (PBS)) was added to each jar. After vigorous stirring (2,500 rpm for 1 min), the solution in each jar was poured on a nutrient agar plate.
where R is the percent reduction, A is the number of bacteria recovered from the inoculated treated test specimen swatches in the jar incubated over 24 h, and B is the number of bacteria recovered from the inoculated treated test specimen swatches in the jar immediately after inoculation (at "0" contact time).
Results and discussions
Static water and water shedding angles of fabricated surface on cotton fabric samples
Kind of surface
Mean of static contact angle "SWC" (°)
Standard error of "SWC"
Mean of waster shedding angle "WSA" (°)
Standard error of "WSA"
The addition of 0.5% wt/wt Cu into silica sol caused the flocculation of colloidal silica nanoparticles (Figure 5b). The emersion of two peaks and the broadening of silica peaks in a size distribution graph just 5 min after introducing Cu nanoparticles may be attributed to the gradual agglomeration of silica and Cu particles (Figure 1b).
Such agglomeration would produce more grape-like clusters on the final fabricated surface. Compared with ordinary SiO2 nanostructured surface, this morphology showed higher air trapping capability and SWC(Table 1).
where R f denotes the roughness factor, and θ and θ 0 are the contact angles of liquid droplets on rough and flat surfaces, respectively. The WSA value for such sample was decreased and reached to 24°, and also, the slippery of treated surface was increased.
Post post hoc test (Duncan's multiple range test) for three samples
Subset for alpha = 0.05
Percent reduction of bacteria on the fabricated control and doped silica surfaces
Undoped silica sol
Copper, especially in its nano scale, has noticeable antibacterial activity with a more low cost compared with other similar antibacterial metals. In addition, the sol-gel method is a conventional process to coat thermo-sensitive substrates like cotton fabrics by nanoparticles. Introducing Cu nanoparticles into silica sol will fabricate a surface with higher air trapping capability on cotton fabrics. Therefore, it can imply superior properties of superhydrophobicity on the substrate and eliminate the need for post-treatment of silica surfaces with alkylsilane. Besides the intrinsic antibacterial properties, disintegration of Cu nanoparticle through the settling on SiO2 particles will simultaneously lead to an efficient antibacterial activity of the surface fabricated. Further study can also be conducted on more interesting properties such as self-cleaning capability of fabricated hierarchical surfaces.
The work is supported by Textile Research Center at Tehran South Branch, Islamic Azad University. We appreciate Mr. Rezaei in Tarbiyat Modarres University for preparing the micrographs of scanning electron microscope and energy dispersive X-ray spectroscopy graphs, and also Mr. Mojtaba Hoseinpour, a member of Advanced Materials & Nanotechnology Research Lab of KNTU University for preparing the micrographs of transmission electron microscope.
- Neinhuis C, Barthlott W: Characterization and distribution of water-repellent, self-cleaning plant surfaces. Annals of Botany 1997, 79: 667–677. 10.1006/anbo.1997.0400View ArticleGoogle Scholar
- Barthlott W, Neinhuis C: Purity of the sacred lotus, or escape from contamination in biological surfaces. Planta 1997, 202: 1–8. 10.1007/s004250050096View ArticleGoogle Scholar
- Mahltig B, Textor T: Improved water, oil and soil repellence. In Nanosols & Textiles. USA: World Scientific; 2008:66–89.View ArticleGoogle Scholar
- Hsieh CT, Wu FL, Yang SY: Superhydrophobicity from composite nano/microstructures: Carbon fabrics coated with silica nanoparticles. Surf Coat Tech 2008, 202: 6103–6108. 10.1016/j.surfcoat.2008.07.006View ArticleGoogle Scholar
- Ma M, Mao Y, Gupta M, Gleason KK, Rutledge GC: Superhydrophobic fabrics produced by electrospinning and chemical vapor deposition. Macromolecules 2005, 38: 9742–9748. 10.1021/ma0511189View ArticleGoogle Scholar
- Shi J, Alves NM, Mano JF: Towards bioinspired superhydrophobic poly(L-lactic acid) surfaces using phase inversion-based methods. Bioinspiration & Biomimetics 2008, 3: 1–6.View ArticleGoogle Scholar
- Han D, Steckl AJ: Superhydrophobic and oleophobic fibers by coaxial electrospinning. Langmuir 2009, 25: 9454–9462. 10.1021/la900660vView ArticleGoogle Scholar
- Heikenfeld J, Dhindsa M: Electrowetting on superhydrophobic surfaces: present status and prospects. J Adhesion Sci Tech 2008, 22: 319–334. 10.1163/156856108X295347View ArticleGoogle Scholar
- Pozzato A, Dal Zilio S, Fois G, Vendramin D, Mistura G, Belotti M, Chen Y, Natali M: Superhydrophobic surfaces fabricated by nanoimprint lithography. Microelectronic Engineering 2006, 83: 884–888. 10.1016/j.mee.2006.01.012View ArticleGoogle Scholar
- Kim SH, Kim JH, Kang BK, Uhm HS: Superhydrophobic CF x coating via in-line atmospheric RF plasma of He-CF4-H2. Langmuir 2005, 21: 12213–12217. 10.1021/la0521948View ArticleGoogle Scholar
- Bae GY, Min BG, Jeong YG, Lee SC, Jang JH, Koo GH: Superhydrophobicity of cotton fabrics treated with silica nanoparticles and water-repellent agent. J Colloid Interface Sci 2009, 337: 170–175. 10.1016/j.jcis.2009.04.066View ArticleGoogle Scholar
- Gao Q, Zhu Q, Guo Y: Formation of highly hydrophobic surfaces on cotton and polyester fabrics using silica sol nanoparticles and nonfluorinated alkylsilane. Ind Eng Chem Res 2009, 48: 9797–9803. 10.1021/ie9005518View ArticleGoogle Scholar
- Hao LF, An QF, Xu W, Wang QJ: Synthesis of fluoro-containing superhydrophobic cotton fabric with washing resistant property using nano-SiO 2 sol-gel method. Adv Mater Res 2010, 121–122: 23–26.View ArticleGoogle Scholar
- Li Z, Xing Y, Dai J: Superhydrophobic surfaces prepared from water glass and non-fluorinated alkylsilane on cotton substrates. Appl Surf Sci 2008, 254: 2131–2135. 10.1016/j.apsusc.2007.08.083View ArticleGoogle Scholar
- Yu M, Gu G, Meng WD, Qing FL: Superhydrophobic cotton fabric coating based on a complex layer of silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent. Appl Surf Sci 2007, 253: 3669–3673. 10.1016/j.apsusc.2006.07.086View ArticleGoogle Scholar
- Xue CH, Jia ST, Zhang J, Tian LQ: Superhydrophobic surfaces on cotton textiles by complex coating of silica nanoparticles and hydrophobization. Thin Solid Films 2009, 517: 4593–4598. 10.1016/j.tsf.2009.03.185View ArticleGoogle Scholar
- Xu B, Cai Z, Wang W, Ge F: Preparation of superhydrophobic cotton fabrics based on SiO2 nanoparticles and ZnO nanorod arrays with subsequent hydrophobic modification. Surf Coat Technol 2010, 204: 1556–1561. 10.1016/j.surfcoat.2009.09.086View ArticleGoogle Scholar
- Mahltig B, Textor T: Nanosol preparation and application. In Nanosols & Textiles. USA: World Scientific; 2008:1–32.View ArticleGoogle Scholar
- Erasmus E, Barkhuysen FA: Superhydrophobic cotton by fluorosilane modification. Indian J Fibre & Textile Res 2009, 34: 377–379.Google Scholar
- Hoefnagels HF, Wu D, De With G, Ming W: Biomimetic superhydrophobic and highly oleophobic cotton textiles. Langmuir 2007, 23: 13158–13163. 10.1021/la702174xView ArticleGoogle Scholar
- Xu B, Cai Z: Fabrication of a superhydrophobic ZnO nanorod array film on cotton fabrics via a wet chemical route and hydrophobic modification. Appl Surf Sci 2008, 254: 5899–5904. 10.1016/j.apsusc.2008.03.160View ArticleGoogle Scholar
- Ravindra S, Murali Mohan Y, Narayana Reddy N, Mohana Raju K: Fabrication of antibacterial cotton fibers loaded with silver nanoparticles via "green approach". Colloids Surf A: Phys Eng Aspects 2010, 367: 31–40. 10.1016/j.colsurfa.2010.06.013View ArticleGoogle Scholar
- Chen CY, Chiang CL: Preparation of cotton fibers with antibacterial silver nanoparticles. Mater Letters 2008, 62: 3607–3609. 10.1016/j.matlet.2008.04.008View ArticleGoogle Scholar
- Xu H, Shi X, Ma H, Lv Y, Zhang L, Mao Z: The preparation and antibacterial effects of dopa-cotton/AgNPs. Appl Surf Sci 2011, 257: 6799–6803. 10.1016/j.apsusc.2011.02.129View ArticleGoogle Scholar
- Hebeish A, El-Shafei A, Sharaf S, Zaghloul S: Novel precursors for green synthesis and application of silver nanoparticles in the realm of cotton finishing. Carbohydrate Polymers 2011, 84: 605–613. 10.1016/j.carbpol.2010.12.032View ArticleGoogle Scholar
- El-Rafie MH, Mohamed AA, Shaheen ThI, Hebeish A: Antimicrobial effect of silver nanoparticles produced by fungal process on cotton fabrics. Carbohydrate Polymers 2010, 80: 779–782. 10.1016/j.carbpol.2009.12.028View ArticleGoogle Scholar
- Perelshtein I, Applerot G, Perkas N, Wehrschuetz-Sigl E, Hasmann A, Guebitz G, Gedanken A: CuO-cotton nanocomposite: formation, morphology and antibacterial activity. Surf Coat Tech 2009, 204: 54–57. 10.1016/j.surfcoat.2009.06.028View ArticleGoogle Scholar
- Grace M, Chand N, Bajpai SK: Copper alginate-cotton cellulose (CACC) fibers with excellent antibacterial properties. J Engineered Fibers and Fabrics 2009, 4: 24–35.Google Scholar
- Chattopadhyay DP, Patel BH: Effect of nanosized colloidal copper on cotton fabric. J Engineered Fibers and Fabrics 2010, 5: 1–6.Google Scholar
- Shateri Khalil-Abad M, Yazdanshenas ME: Superhydrophobic antibacterial cotton textiles. J Colloid Interface Sci 2010, 351: 293–298. 10.1016/j.jcis.2010.07.049View ArticleGoogle Scholar
- Vilcnik A, Jerman I, Surca Vuk A, Kozelj M, Orel B, Tomsic B, Simoncic B, Kovac J: Structural properties and antibacterial effects of hydrophobic and oleophobic sol-gel coatings for cotton fabrics. Langmuir 2009, 25: 5869–5880. 10.1021/la803742cView ArticleGoogle Scholar
- Yang H, Deng Y: Preparation and physical properties of superhydrophobic papers. J Colloid Interface Sci 2008, 325: 588–593. 10.1016/j.jcis.2008.06.034View ArticleGoogle Scholar
- Kim YH, Kim CW, Cha HG, Cha HJ, Kang YC, Kang YS, Jo B, Ahn GW: Preparation and characterization of Cu-SiO 2 nanocomposite. Molecular Crystals and Liquid Crystals 2009, 515: 251–254. 10.1080/15421400903479872View ArticleGoogle Scholar
- Cioffi N, Torsi L, Ditaranto N, Tantillo G, Ghibelli L, Sabbatini L, Bleve-Zacheo T, D'Alessio M, Zambonin PG, Traversa E: Copper nanoparticle/polymer composites with antifungal and bacteriostatic properties. Chem Mater 2005, 17: 5255–5262. 10.1021/cm0505244View ArticleGoogle Scholar
- Kim YH, Lee DK, Cha HG, Kim CW, Kang YC, Kang YS: Preparation and characterization of the antibacterial Cu nanoparticle formed on the surface of SiO 2 nanoparticles. J Phys Chem B 2006, 110: 24923–24928. 10.1021/jp0656779View ArticleGoogle Scholar
- Zhang N, Gao Y, Zhang H, Feng X, Cai H, Liu Y: Preparation and characterization of core-shell structure of SiO2@Cu antibacterial agent. Colloids Surf B Biointerfaces 2010, 81: 537–543. 10.1016/j.colsurfb.2010.07.054View ArticleGoogle Scholar
- Stöber W, Fink A, Bohn E: Controlled growth of mono disperse silica spheres in the micron size range. J Colloid Interface Sci 1968, 26: 62–69. 10.1016/0021-9797(68)90272-5View ArticleGoogle Scholar
- Zimmermann J, Seeger S, Reifler FA: Water shedding angle: a new technique to evaluate the water-repellent properties of superhydrophobic surfaces. Textile Research Journal 2009, 79: 1565–1570. 10.1177/0040517509105074View ArticleGoogle Scholar
- Rao KS, El-Hami K, Kodaki T, Matsushige K, Makino K: A novel method for synthesis of silica nanoparticles. J Colloid Interface Sci 2005, 289: 125–131. 10.1016/j.jcis.2005.02.019View ArticleGoogle Scholar
- Ibrahim IAM, Zikry AAF, Sharaf MA: Preparation of spherical silica nanoparticles: Stober silica. J American Sci 2010, 6: 985–989.Google Scholar
- Cassie ABD, Baxter S: Wettability of porous surfaces. Trans Faraday Soc 1944, 40: 546–551.View ArticleGoogle Scholar
- Nosonovsky M, Bhushan B: Superhydrophobic surfaces and emerging applications: non-adhesion, energy, green engineering. Current Opinion in Colloid Interf Sci 2009, 14: 270–280. 10.1016/j.cocis.2009.05.004View ArticleGoogle Scholar
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