Robust ZnO/HNTs-Based Superhydrophobic Cotton Fabrics With UV Shielding, Self-Cleaning, Photocatalysis, and Oil/Water Separation

doi:10.21203/rs.3.rs-978060/v1

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Research Article

Robust ZnO/HNTs-Based Superhydrophobic Cotton Fabrics With UV Shielding, Self-Cleaning, Photocatalysis, and Oil/Water Separation

https://doi.org/10.21203/rs.3.rs-978060/v1

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published 19 Mar, 2022

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In this work, robust superhydrophobic cotton fabrics with UV shielding, self-cleaning, photocatalysis, and oil/water separation were successfully prepared based on micro/nano hierarchical ZnO/HNTs (halloysite nanotubes) hybrid particles and silicone elastomer polydimethylsiloxane (PDMS). ZnO/HNTs hybrid particles were prepared by in-situ growth of ZnO nanoparticles on the surface of halloysite nanotubes (HNTs). ZnO/HNTs hybrid particles and PDMS were used to successively coat cotton fabric by dip-coating approach. The coated cotton fabric displayed excellent superhydrophobicity with a water contact angle of 162.5 ± 1° and photocatalytic degradation of methylene blue solution under UV irradiation owing to the roughness and photocatalytic performance provided by micro/nano hierarchical ZnO/HNTs hybrid particles and low surface energy achieved by PDMS. The as-prepared fabric also displayed outstanding self-cleaning and antifouling properties. In addition, due to its both superhydrophobic and superoleophilic characteristics, the as-prepared cotton fabric can be used to separate several oil/water mixtures and showed good recoverability. The superhydrophobic cotton fabric also exhibited excellent UV shielding performance with a large UV protection factor of 1643.28 due to strong ultraviolet-absorption, light scattering and frequent light reflection of ZnO nanoparticles in ZnO/HNTs composites coated on cotton fabric. Importantly, the as-prepared fabric retained superhydrophobic performance after 2000 cycles rubbing, 90h UV illumination, and immersing in acidic and alkali solutions with different pH values ranging from 1 to 14 for 1 h. These characteristics make multifunctional cotton fabrics a satisfactory candidate in various promising fields.

Cellular & Molecular Neuroscience

Cellular Metabolism

superhydrophobic

ZnO/HNTs hybrid particles

self-cleaning

Photocatalysis

UV shielding

oil/water separation

cotton fabrics

Cotton fabrics, one of the most common natural cellulosic fabrics, are used in costume, household textiles, and outdoor protection because of their softness, low cost, air permeability and environmental friendliness. Unfortunately, the cotton fabric can be easily wetted and contaminated by liquids such as water and cola owing to the great number of surface hydroxyl groups on the cellulose fibers of cotton fabric (Zhou et al. 2018). It has been demonstrated that introduction of superhydrophilicity is a sample and effective strategy to overcome the above-mentioned disadvantages (Xu et al. 2020; Yang et al. 2019; Yang et al. 2018).

Inspired by lotus leaf, many researches confirmed that preparation of superhydrophobic surfaces required the coordination of hierarchical micro/nano structures and ultralow surface free energy (Zhang et al. 2019; Shishodiaa et al. 2019; Tu et al. 2017). A large number of methods have been developed to prepare artificial superhydrophobic surfaces, such as layer-by-layer self-assembly technique (Lin et al. 2018, Jiang et al. 2017), deposition method (Rezaei et al. 2014; Gang et al. 2017), sol-gel method (Zhang et al. 2017; Banerjee et al. 2015), and spray method (Gao et al. 2017). However, to construct superhydrophobic surfaces, the fluoro compounds with ultralow surface energy are widely used, and they display excellent repellence to a wide range of liquids (such as water, glycerol, sunflower oil, n-hexadecane) (Kim et al. 2018; Ma et al. 2017; Wang et al. 2019). Unfortunately, the expensive long-chain perfluoroalkyl materials have a potential environmental risk due to difficult biodegradation, long-distance migration, and high bioaccumulation(Zuo et al. 2018; Martin et al. 2003; Cao et al. 2016). Recently, polydimethylsiloxane (PDMS) is an ideal candidate for the fabrication of superhydrophobic surface owing to its low surface energy, environmental friendliness, strong adhesion, and excellent chemical, thermal stability. Cao et al. have reported an environmentally friendly strategy to prepare robust superhydrophobic fabric by dipping in silica aerogel (ormosil) solution and PDMS solution respectively, which possessed self-cleaning and oil-water separation property (Cao et al. 2016). Zheng et al. studied a self-assembly approach to prepare conductive superhydrophobic cotton fabric, which employed carboxylated and aminated multiwalled carbon nanotubes to create hierarchical roughness with modification with PDMS (Zheng et al. 2019).

Moreover, for preparation of superhydrophobic surfaces, the construction of these micro/nano hierarchical structures often depends on synthetic nanoparticles (Lin et al. 2017; Jin et al. 2018), etching (Wen et al. 2017; Kim et al. 2007), and template (Jin et al. 2005). These building blocks applied for superhydrophobic coatings are often costly, complicated in process, and can easily cause environmental pollution problems, restricting broader applications. Superhydrophobic surface based on naturally occurring nanomaterials are strongly advocated, but so far, only a very few superhydrophobic coatings with natural nanomaterials have been developed. Zhang et al. obtained waterborne nonfluorinated superhydrophobic coatings based on natural nanorods, palygorskite (PAL), followed by methyl polysiloxane modification with polyurethane (PU) as the adhesive layer (Zhang et al. 2017). Qu et al. fabricated superamphiphobic materials employing kaolin particles and silanes (Qu et al, 2018). HNTs (halloysite nanotubes) is a kind of natural aluminosilicate clay mineral with a unique needlelike microstructure. The one-dimensional structure, large surface area, low cost, and tunable surface chemistry of HNTs could benefit for their application in the construction of organic-inorganic nanohybrid materials (Ma et al. 2018). The re-entrant structure could be formed when nanoparticles were introduced on surfaces of HNTs, resulting in rod-dot hybrid particles. Hierarchical micro/nano structures could be generated when a great number of rod-dot hybrid particles aggregated and/or stacked, and the vacancies or pores may be filled with air, showing the potential for water repellency. Liu et al. have reported a facile surface coating technique to fabricate superamphiphobic protein-based films materials based on fluorinated HNTs/SiO₂ particles (Liu et al. 2019). The micro/nano hierarchical HNTs/SiO₂ particles were prepared via situ growth of SiO₂ on the surface of HNTs though sol-gel method.

ZnO nanoparticles is characterized by eco-friendly, low cost, ultraviolet-proof, biocompatibility and photocatalysis activity, which could be used to prepare superhydrophobic surface and has potential applications in the field of multifunctional textiles(Yang et al. 2019). Yang et al. obtained multifunctional cotton textiles based on PDMS/ZnO composite solution via one-pot dip-coating method (Yang et al. 2019). Moreover, some studies reported that ZnO nanoparticle assembled on HNTs can improve photocatalytic activity and absorptivity. Cheng et al. reported an impregnation method to successfully synthesize N-doped ZnO nanoparticle assembled into HNTs, which exhibited remarkable photocatalytic activity compared to pure ZnO nanoparticles (Cheng et al. 2015). So far there is rare report on the facile fabrication of superhydrophobic cotton fabrics with self-cleaning, UV shielding, photocatalysis, and oil/water separation using hierarchical ZnO/HNTs hybrid particles.

In this paper, HNTs was used as the initial building block to prepare robust, superhydrophobic cotton fabrics with self-cleaning, UV shielding, photocatalysis, and oil/water separation after in-situ growth of ZnO nanoparticles. The surface morphologies, chemical composition, wettability, mechanical durability, UV stability, and anti-corrosion, self-cleaning, photocatalysis, and oil/water separation performances of all samples were characterized. These results demonstrated that the obtained multifunctional cotton fabric showed wide application even in harsh environment.

2.1 Materials

Zinc nitrate (Zn(NO₃)₂.6H₂O), methylene blue (MB), ammonium hydroxide (NH₃.H₂O,30%) were offered by Sinopharm Chemical Reagent Co. (China). Polydimethylsiloxane (PDMS) with the curing agent was purchased from Dow Corning Co. (USA). The halloysite nanotubes (HNTs, purity > 97%) were purchased from Ishu International.

2.2 Preparation of ZnO/HNTs nanocomposites

ZnO/HNTs nanocomposites were synthesized via situ growth of ZnO on the surface of HNTs by sol-gel method. Firstly, 2g Zn(NO₃)₂.6H₂O and 0.5g HNTs were added into 100 mL of deionized water and were stirred vigorously to form a homogenous solution at room temperature. Then pH of solution was adjusted to 9-10 with NH₃.H₂O. The mixed solution was further reacted at 60 °C for 2 h to obtain the ZnO/HNTs sol. After centrifugal washing and drying, a white powder was obtained. Finally, it was calcined in a muffle furnace at 450°C for 2 h to obtain a ZnO/HNTs hybrid particles.

2.3 Fabrication of ZnO/HNTs/[email protected], HNTs/[email protected], and [email protected]

Firstly, appropriate ZnO/HNTs hybrid particles were dispersed in water to formed homogeneous solution A. Besides, a certain amount of PDMS and curing agent (PDMS: 10:1 curing agent by mass ratio) were added to tetrahydrofuran to form solution B. The clean cotton fabric sample was immersed in the solution A and then dried at 80 °C. The obtained cotton fabric was called as ZnO/[email protected] Then the as-prepared ZnO/[email protected] was dipped in the solution B and then cured at 130 °C for 0.5 h in an oven. The resultant cotton fabrics were named as ZnO/HNTs/[email protected] The cotton fabric sample [email protected] coated by only PDMS was also prepared by the same method.

2.4 Sample characterization

The surface morphologies of samples were observed by using scanning electron microscope (SEM, Hitachi S-4800). The element distribution of cotton surface was examined by an energy dispersive spectrometer (EDS, Escalab250Xi). Chemical groups of samples were identified by Fourier transformer infrared spectrometer (Nicolet IS 10, Thermo, USA). Thermogravimetric analysis (TGA) was tested using a thermogravimetric analyzer (Q500, TA, USA). The UV-blocking property of the samples was measured by a Labsphere UV-2000 ultraviolet transmittance analyzer.

Wettability test

The static water contact angles (WCA) of cotton fabric surface were tested by Krüss DSA 30 (Krüss, Germany). The water shedding angle (WSA) was tested according to reported literature (Wu et al. 2013; Zhang et al. 2013). The average of five values from same sample was defined as the final WCA and WSA of the cotton fabric surface.

Durability test

The abrasion resistance was measured by a fabric abrasion tester according to previous literature (Xu et al. 2020). The superhydrophobic cotton fabric was illuminated under a UV lamp of 150 W for 90 h continuously. The contact angles of the ZnO/HNTs/[email protected] were recorded to evaluate the UV resistance. The chemical stability of the modified cotton fabric was investigated by testing contact angles of modified cotton fabric after immersing into corrosive liquids with different pH levels ranging from 1 to 14 for 1 h.

Oil/water separation test and oil absorption test

The oil/water separation experiment of coated cotton fabric was carried out by using a simple and facile laboratory-made setup. The coated cotton fabric was placed between cylindrical filter funnel and conical flask as filter membrane, and the 100 ml yellow oil and 100 ml blue water mixed solution were poured into the funnel. The separation efficiency (η) was calculated according to , where M_After and M_Before is the quality of the oil/water mixed solution before and after separation process.

The flux was obtained according to , where V is the volume of oil permeated coated fabric, S is valid area of the film, and t is the time for collect of V ml of oil.

Photocatalytic activity

The photocatalytic activity of the superhydrophobic cotton fabric with the size of 3 cm × 5 cm and other samples were investigated by degrading 10 mg/L methylene blue (MB) solution. To avoid adsorption effects, the samples were magnetically stirred thoroughly in the dark environment until reaching the adsorption–desorption equilibrium of MB with photocatalyst before 150W high-pressure Hg lamp. Every 30 minutes, 2ml of the reaction solution was extracted and centrifuged to remove photocatalyst particles. Then the corresponding absorbance of the characteristic peak at 665 nm was measured by UV-visible absorption spectrum to record the concentration change of MB.

3.1 Preparation of ZnO/HNTs and ZnO/HNTs/[email protected]

The preparation process of the ZnO/HNTs and ZnO/HNTs/[email protected] was schematically shown in Fig. 1. First, the Zn²⁺ ionized by Zn(NO₃)₂.6H₂O in the aqueous solution attracts water molecules to forme the solvent unit Zn(H₂O)₂. The solvent unit releases H⁺ in an alkaline environment to maintain the coordination number to generate the precursor Zn(OH)₂. Zn(OH)₂ combined with Al-OH and Si-OH groups on the inner and outer walls of HNTs nanotubes by hydrogen bonding. The active sites on the inner and outer surfaces of the HNTs nanotubes can play a role in dispersing the precursors and prevent the precursors from agglomerating. Subsequently, the precursor-loaded HNTs nanotubes were calcined at a high temperature of 450°C to obtain ZnO/HNTs nanocomposites. Then, the pristine cotton fabric was dipped into micro/nano hierarchical ZnO/HNTs hybrid particles dispersion to obtain ZnO/[email protected] The ZnO/HNTs hybrid particles dispersion can endow fibers desirable roughness, which could generate micro/nano hierarchical structure combined with the natural morphology of the cellulose fiber. Finally, the ZnO/[email protected] was modified by PDMS to obtain superhydrophobic cotton fabric,which can lowered the surface tension of ZnO/[email protected]

3.2 Characterization of ZnO/HNTs and superhydrophobic cotton fabrics

The surface morphology of HNTs, ZnO/HNTs, [email protected] and ZnO/HNTs/[email protected] were observed by SEM. As illustrated in Fig. 2A, HNTs showed a homogeneously nanorod-like structure with a length and a diameter range of 0.7-1.5 µm and 30-50 nm, respectively. Compared to nanorod-like structures of the HNTs, the ZnO/HNTs hybrid particles exhibited unique rod-dot micro/nano hierarchical structures when the ZnO nanoparticles were introduced on surfaces of HNTs (Fig. 2C, D). [email protected] fabric with relative smooth surface, but there were still special folds and grooves in the longitudinal direction (Fig. 2E, F). In contrast, the ZnO/HNTs/[email protected] became much rougher, with particulate protrusions compacted on the cotton fabric surface (Fig. 2G). Moreover, the higher magnification SEM image of ZnO/HNTs/[email protected] shown in Fig. 2H revealed that ZnO/HNTs coating was covered with a thin layer of PDMS coating.

For further investigation of coated cotton fabric, the chemical components of the untreated cotton fabric, [email protected], and ZnO/HNTs/[email protected] were characterized by EDS and FTIR. As shown in Fig. 2J, the C, O, Si and Zn elements were distributed on the surface of the coated fabric, suggesting the successful coating of ZnO/HNTs and PDMS on coated fabric surface and ZnO/HNTs/[email protected] was successfully prepared. In addition, the uniform distribution of C, O, Zn and Si elements indicated that ZnO/HNTs hybrid particles and PDMS were evenly covered on cotton surface (Fig. 2I).

As shown in Fig. 3A, in FT-IR spectrum of pristine cotton fabric, it could be clearly observed from the infrared spectrum that a strong and broad absorption peak appeared at 3332 cm⁻¹, which was the characteristic peak of the stretching vibration of the hydroxyl group in the cellulose macromolecule of the pristine cotton fabric. Two characteristic absorption peaks can be observed at 2893 cm⁻¹ and 1310 cm⁻¹, namely -CH₃ stretching vibration and bending vibration absorption. The strongest absorption peak at 1027 cm⁻¹ originated from the flexural vibration of the hydroxyl group (-OH) in the cotton cellulose macromolecule and the C-O-C stretching vibration absorption. When the cotton fabric was coated with PDMS, new peaks at 2967 cm⁻¹, 1258 cm⁻¹, and 783 cm⁻¹ occurred, which were assigned to –CH₃ stretching vibration, Si–C bend vibration and Si–O–Si symmetrical stretching vibration, respectively, which were due to a lot of -CH₃ groups and Si–O–Si groups of PDMS. The appearance of these characteristic peaks indicated that PDMS had been successfully grafted onto cotton fabrics. Compared with [email protected], there were no obvious new bands from FT-IR spectra of ZnO/HNTs/[email protected]

The thermal stability of the ZnO, ZnO/HNTs, pristine cotton fabric, [email protected] and ZnO/HNTs/[email protected] were investigated by thermo gravimetric analysis. As shown in Fig. 3B, there was 11% weight loss at temperatures below 350°C in the case of the pristine cotton fabric, and the weight loss was 13% for [email protected] and 10% for ZnO/HNTs/[email protected], respectively. The weight loss of the samples from room temperature to 350 ℃ was small, mainly due to the water volatilization and impurities decomposition which absorbed on cotton fabric surface. From 350℃ to 420℃, the weight loss of pristine cotton fabric was 78.5% because of the decomposition of cellulose. Untreated cotton fabric showed residual weight rate of about 0.01% after being heated to 700℃ because of the residual groups (such as -CH₂-, etc.) decomposition. It was indicated that there was little pristine fabric left. In contrast, the remaining weight percentage of [email protected] was 2.3%, which was higher than 0.3% of pristine cotton fabric. This was mainly caused by the incomplete decomposition of PDMS at high temperature. However, for ZnO/HNTs/[email protected], the residual weight percentage reached to 9.1%, showed the improved thermal stability. As mentioned above, ZnO/HNTs hybrid particles had excellent thermal stability. Thereby, TG result of ZnO/HNTs/[email protected] revealed the successful incorporation of ZnO/HNTs hybrid particles and PDMS on the cotton fabric surface.

3.3 Wettability of superhydrophobic cotton fabrics

Surface roughness and chemical composition are two key factors for preparation of superhydrophobic surface. Therefore, the controlled variable method was adopted to study the wettability of coated cotton fabric by changing the content of Zn(NO₃)₂.6H₂O and PDMS. As displayed in Fig. 4A, the HNTs/[email protected] exhibited hydrophobicity with a water contact angle of 143.9±1.2°. This result indicating that the only HNTs and PDMS were unable to endow pristine cotton fabric superhydrophobicity. With the mass fraction of Zn(NO₃)₂.6H₂O increasesed to 2 wt. %, the ZnO/HNTs/[email protected] displayed the superhydrophobicity with a WCA of 162.5±1°. This result can be explained that the cotton fabric surface was composed of hierarchical micro/nano structures with higher roughness after modified by ZnO/HNTs hybrid particles. However, the superhydrophobicity of ZnO/[email protected] was negatively affected by the further increase of Zn(NO₃)₂.6H₂O mass fraction (6 wt. %), the WCA was 150.2±0.7°. This may be caused by the slight disappearance of the micro/nano hierarchical structure of ZnO/HNTs/[email protected] due to excessive Zn(NO₃)₂.6H₂O, resulting in a decrease in roughness. Therefore, Zn(NO₃)₂.6H₂O with mass fraction of 2 wt. % was the optimal choice for subsequent experiments.

Similarly, in Fig. 4B, for only the ZnO/HNTs hybrid particles were employed to the pristine cotton fabric, the ZnO/[email protected] was easily wetted due to the inherent hydrophilic properties of the ZnO/HNTs hybrid particles and cellulose. The WCA of ZnO/[email protected] increased dramatically from 0° to 148.1±1° even if only 5% of PDMS was introduced. This was because the introduction of PDMS lowered the surface tension of ZnO/[email protected] As the PDMS mass fraction was up to 15%, the WCA of ZnO/[email protected] increased to 162.5±1° and the rolling angle dropped to 4°. However, the WCA of ZnO/[email protected] decreased to 152.4±0.8° when the mass fraction of PDMS reached 25%. This was because excessive PDMS completely cover ZnO/HNTs hybrid particles hierarchical micro/nano structure, which made the surface of ZnO/HNTs/[email protected] too smooth to construct roughness.

To further evaluate superhydrophobic property of the coated cotton fabric, the Cassie-Baxter model was used to explain the influence of hierarchical rough surface on wettability. According to Cassie-Baxter’s equation, the apparent contact angle on the surface(θ^*) is calculated as

cosθ * = rfcosθ＋f－1 (1)

where θ presents the Young’s contact angle that is obtained on the slippy surface with the same composition, r is the actual wetted area divided by the projected wetted area of the surface, f is the fraction of the projected area of the solid surface contacting the liquid.

In Equation (1), r is greater than 1, f is less than 1, and both are positive. The θ < 90° is due to the natural hydrophilic properties of cotton fabric. Therefore, if f is small enough, θ^*can be greater than 150° according to equation (1). One strategy to minimize the f value is to increase the surface roughness of the material, such as flower-like structure, and micro/nano re-entrant structure. As shown in Fig. 5A, after HNTs and PDMS coating, HNTs/[email protected] showed hydrophobicity with a WCA of 143.9°. Compared with the microrod-like HNTs stacked coating, the roughness factor of ZnO nanoparticles has increased, showing a certain degree of superhydrophobicity with a water contact angle of 152.4° (Fig. 5B). In this paper, a micro-/nano hierarchical re-entrant structure was constructed by depositing ZnO nanoparticles onto the rod-like HNTs surfaces. As displayed in Fig. 5C, the deposition of ZnO nanoparticles further increases the surface roughness of ZnO/HNTs hybrid particles, resulting in a significant reduction in the liquid/solid contact area. The coated cotton fabric displayed excellent superhydrophobicity with a water contact angle of 162.5° due to could trap the more air layer.

The surface wettability of superhydrophobic cotton fabrics were analyzed by evaluating their static/dynamic wettability performances and antifouling ability. As shown in Fig. 6A, different liquid droplets including blue colored water, juice, and cola were dropped on pristine cotton fabric and ZnO/HNTs/[email protected] These aqueous droplets collapsed on the untread cotton fabric due to its hydrophilic nature. In contrast, the ZnO/HNTs/[email protected] could hold on all liquid droplets in a spherical shape without any penetration. When pristine cotton fabric and ZnO/HNTs/[email protected] were immersed in water, photographs of cotton fabrics were shown in Fig. 6B. The untreated cotton fabric promptly sank to the bottom of water. However, ZnO/HNTs/[email protected] can float on water without any wetting. As illustrated in Fig. 6C, when the fixed ZnO/HNTs/[email protected] was immersed in water, a sliver mirror surface was observed due to the existence of an air cushion surrounded by the coating. Additionally, a jet of red water could easily bounce off from the coated cotton fabric surface without leaving a trace. In contrast, a jet of red colored water easily wet on pristine cotton fabric (Fig. 6D, E).

3.4 Durability evaluation of the superhydrophobic cotton fabrics

In practical applications, most of superhydrophobic coatings easily lose their superhydrophobicity under harsh conditions, such as mechanical abrasion and UV irradiation. As illustrated in Fig. 7A, after 2000 abrasion cycles, the WCA of ZnO/HNTs/[email protected] showed only slight change, still higher than 150°. This result indicated that ZnO/HNTs hybrid particles with silicone elastomer PDMS coating still maintained excellent superhydrophilicity after mechanical abrasion although ZnO/HNTs hybrid particles of the fiber surface was partially destroyed (Fig. 7B). This was attributed to PDMS, which not only lowered the surface energy of the coating, but also formed a dense film on the surface of the cotton fabric coating and bonded the ZnO/HNTs hybrid particles tightly on the surface of the cotton fiber to enhance the mechanical durability of superhydrophobic cotton fabric. In addition, as presented in Fig. 7C the WCAs of superhydrophobic cotton fabric remained around 150° after 150W UV irradiation for 90h, showing good UV-durability. From Fig. 7D, typical micro/nano hierarchical structure was retained on the microscale fiber surface of ZnO/HNTs/[email protected] after UV irradiation for 90h. This was mainly due to the anti-ultraviolet properties of ZnO/HNTs hybrid particles and the strong bond energy of the -Si-O-Si- bond contained in the PDMS layer, which made PDMS resistant to UV decomposition Moreover, the chemical stability of the coated cotton fabric was also evaluated. The influence of acid and alkali on the wettability of the superhydrophobic cotton fabric was tested by immersing in different pH value solutions ranging from 1 to 14 for 1 h. As displayed in Fig. 7E, the WCA of ZnO/HNTs/[email protected] after dipping in solution with pH value varying from 1 to14 still kept higher than 151°. As shown in Fig. 7F, there were still hierarchical rough morphology on ZnO/HNTs/[email protected] fiber surface. These results indicated that the prepared cotton fabric showed great potential in arousing consumer interest and large-scale industrial applications.

3.5 Self-cleaning antifouling performance

Self-cleaning behavior refers to the phenomenon that various contaminants on solid surfaces can be eliminated under natural circumstance. To investigate self-cleaning of the cotton fabric samples prepared in this study, a layer of methyl orange powder was used as contaminant. When a continuous process of water droplets was dropped onto ZnO/HNTs/[email protected] surface, they quickly rolled off and picked up the dissolved methyl blue powder without adhering to it (Fig. 8A). Consequently, the preferable superhydrophobic self-cleaning ability of the ZnO/HNTs/[email protected] was confirmed.

Moreover, to demonstrate the excellent antifouling ability of the superhydrophobic cotton fabric, liquid pollutants experiments were carried out. As presented in Fig. 8B, the ZnO/HNTs/[email protected] was immersed in red colored aqueous solutions and then taken out. The superhydrophobic cotton fabric still maintained dry without any residue due to the presence of a layer of air between the surface and the liquid, which protects the cotton fabric from wetting.

3.6 Photocatalytic performance

To investigate the photocatalytic degradation of samples, photodegradation experimental toward MB was carried out. Fig. 9A displayed the photodegradation efficiencies of ZnO, ZnO/HNTs, ZnO/[email protected], and ZnO/HNTs/[email protected] toward MB under UV-vis irradiation. Fig. 9B given the UV–vis absorption spectra of MB in ZnO/HNTs/[email protected] photocatalytic process. As can be seen in Fig. 9A, the ZnO photodegradation efficiencies reached 98% after UV-vis irradiation about 1.5 hours. While the absorption bands of MB solution in the presence of the ZnO/HNTs hybrid particles decreased significantly and 96.7% photodegradation efficiencies was obtained after UV-vis irradiation for 0.5 hours. The excellent photocatalytic performance of the ZnO/HNTs hybrid particles may be ascribed the active sites on the inner and outer surfaces of HNTs hinder the agglomeration of precursors to form smaller-sized ZnO nanoparticles and HNTs support as adsorbent. Compared with ZnO/HNTs photocatalyst, ZnO/[email protected] and ZnO/HNTs/[email protected] takes longer time to achieve the similar photocatalytic efficiencies. Interestingly, ZnO/[email protected] mostly floated on the surface of methyl blue dilution because of its excellent superhydrophobicity. Undoubtedly, this great superhydrophobicity of ZnO/[email protected] negatively affected its degradation effect in this experiment. When ZnO/[email protected] was coated on cotton fabric, its photocatalytic efficiencies were reduced. This was because the contact area between ZnO/HNTs/[email protected] and methylene blue was smaller than that of ZnO/[email protected] As can be seen in Fig. 9B, in 0-3 h, the degradation rate of ZnO/HNTs/[email protected] to MB gradually decreases. This can be attributed to the fact that in the range of 0-3h, as the degradation reaction progresses, the MB concentration in the system gradually decreased, resulting in the gradually decreased of the contact between ZnO/HNTs/[email protected] and MB. When the degradation reaction progressed to 3h, the degradation rate of ZnO/HNTs/[email protected] to MB gradually increased. This can be explained by the fact that as the degradation reaction progresses, the hydrophobicity of ZnO/HNTs/[email protected] was getting worse and the contact surface with MB gradually becames larger, and this effect was greater than the reduction of MB concentration in the system on the degradation reaction.

3.7 Oil-water separation of the superhydrophobic cotton fabrics

The ZnO/HNTs/[email protected] possessed both superhydrophobic and superoleophilic characteristics and had a certain attraction for the separation of oil/water mixtures. Herein, dichloromethane was used to measure the oil/water separation ability of the ZnO/HNTs/[email protected] Fig. 10A shown the separation processes of dichloromethane by the as-prepared cotton fabric. As expected, while the dichloromethane/water mixture was poured into the filter apparatus, yellow dichloromethane could permeate through the superhydrophobic cotton fabric filter membrane instantaneously due to gravity, leaving only the water above the filter. After 10 cycles of separation, the superhydrophobic cotton fabric still exhibited high separation efficiency, and the separation efficiency and flux of dichloromethane/water mixture was up to 94.6% and 636 Lm⁻²s⁻¹, indicating excellent recyclability (Fig. 10B). As displayed in 10C, with the increase of oil/water separation cycles, WCA of ZnO/HNTs/[email protected] decreased slightly but remained above 150°. These results above mentioned demonstrated that ZnO/HNTs/[email protected] showed wide application prospects in the field of oil/ water separation.

3.8 UV-shielding property of the superhydrophobic cotton fabrics

Figure 10 shows the ultraviolet transmittance spectra and UPF values of pristine cotton fabric, [email protected], and ZnO/HNTs/[email protected] From Fig. 11, pristine cotton fabric and [email protected] displayed similar transmittances curves and didn’t show UV shielding performance. In comparison, pristine cotton fabric and [email protected], ZnO/HNTs/[email protected] exhibited high UV shielding effect and UPF value significantly improved to 1643.28 and T(UVA) and T(UVB) were only 0.3% and 0.05%, respectively. This result was attributed to strong ultraviolet-absorption, light scattering and frequent light reflection of ZnO nanoparticles in ZnO/HNTs hybrid particles coated on cotton fabric (Momen et al. 2012).

In summary, a facile approach to prepare robust, ultraviolet-proof superhydrophobic cotton fabric based on PDMS and hierarchical ZnO/HNTs hybrid particles for self-cleaning, photocatalysis, and oil/water separation. When the mass fraction of Zn(NO₃)₂.6H₂O and PDMS were 2% and 15% respectively, the prepared coated cotton fabric achieved superhydrophobicity with a WCA of 162.5 ± 1°. Moreover, the superhydrophobic fabric displayed desirable self-cleaning, antifouling, photocatalysis, and oil/water separating performance. The prepared functional cotton fabric also demonstrated good ultraviolent-proof performance. Importantly, the superhydrophobic cotton fabric was stable enough to withstand mechanical abrasion test, chemical corrosion, and UV irradiation. This work provides a low cost and environmentally friendly approach for development of multifunctional textiles, which can be employed in self-cleaning, degradation of dye waste and UV shielding fields.

Acknowledgements

This work was financially supported by Shanghai Natural Science Foundation (21ZR426200); National Natural Science Foundation of China (51703123).

Zhou Q Q, Chen G Q, Xing T L (2018) Facile construction of robust superhydrophobic tea polyphenol/[email protected] fabric for self-cleaning and efficient oil–water separation. Cellulose 25:1513–1525. https://doi.org/10.1007/s10570-018-1654-1
Xu L H, Liu Y D, Yuan X L, Wan J, Wang L M, Pan H, Shen Y (2020) One-pot preparation of robust, ultraviolet-proof superhydrophobic cotton fabrics for self-cleaning and oil/water separation. Cellulose 27:9005-9026. https://doi.org/10.1007/s10570-020-03369-2
Yang M P, Liu W Q, Jiang C, Xie K Y, Shi H Y, Zhang F Y (2019) Facile fabrication of robust fluorine-free superhydrophobic cellulosic fabric for self-cleaning, photocatalysis and UV shielding. Cellulose 26: 8153-8164. https://doi.org/10.1007/s10570-019-02640-5
Yang M P, Liu W Q, Jiang C, Liu C H, He S, Xie Y K, Wang Z F (2018) Facile Preparation of Robust Superhydrophobic Cotton Textile for Self-Cleaning and Oil-Water Separation. Ind Eng Chem Res 58: 187-194. https://doi.org/10.1021/acs.iecr.8b04433
Zhang X T, Liu S Q, Salim A, Seeger S (2019) Hierarchical structured multifunctional self-cleaning material with durable superhydrophobicity and photocatalytic functionalities. Small 15(34):1901822. https://doi.org/10.1002/smll.201901822
Shishodiaa A, Aroraa H S, Babua A, Mandalb P, Grewala H S (2019) Multidimensional durability of superhydrophobic self-cleaning surface derived from rice-husk ash. Prog Org Coat 136:105221. https://doi.org/10.1016/j.porgcoat.2019.105221
Tu Y Y, Zou H L, Lin S D, Hu J W (2017) Understanding the mechanism for building woven fabrics with wettability ranging from superhydrophobic to superamphiphobic via an aqueous process. React Funct Polym 119:75-81. https://doi.org/10.1016/j.reactfunctpolym.2017.08.004
Lin D M, Zeng X R, Li H Q, Lai X J (2018) Facile fabrication of superhydrophobic and flame-retardant coatings on cotton fabrics via layer-by-layer assembly. Cellulose 25: 3135-3149. https://doi.org/10.1007/s10570-018-1748-9
Jiang B, Zhang H J, Sun Y L, Zhang L H, Xu L D, Hao L, Yang H W (2017) Covalent layer-by-layer grafting (LBLG) functionalized superhydrophobic stainless steel mesh for oil/ water separation, Appl Surf Sci 406:150-160. https://doi.org/10.1016/j.apsusc.2017.02.102
Rezaei S, Manoucheri I, Moradian R, Pourabbas B (2014) One-step chemical vapor deposition and modification of silica nanoparticles at the lowest possible temperature and superhydrophobic surface fabrication. Chem Eng J 252: 11-16. https://doi.org/10.1016/j.cej.2014.04.100
Gang W, Guo Z G, Liu W M (2017) Biomimetic polymeric superhydrophobic surfaces and nanostructures: from fabrication to applications. Nanoscale 9: 3338-3366. https://doi.org/10.1039/c7nr00096k
Zhang D Q, Williams B L, Shrestha S B, Nasir Z, Becher E M, Lofink B J, Santos V H, Patel H, Peng X H, Sun L Y (2017) Flame retardant and hydrophobic coatings on cotton fabrics via sol-gel and self-assembly techniques. J Colloid Interf Sci 505:892-899. https://doi.org/10.1016/j.jcis.2017.06.087
Banerjee S, Dionysios D D, Pillai S C (2015) Self-cleaning applications of TiO₂ by photo-induced hydrophilicity and photocatalysis. Appl Catal B-Environ 176: 396-428. https://doi.org/10.1016/j.apcatb.2015.03.058
Gao S W, Dong X L, Huang J Y, Li S H, Chen Z, Lai Y K (2017) Rational construction of highly transparent superhydrophobic coatings based on a non-particle, fluorine-free and water-rich system for versatile oil-water separation. Chem Eng J 333: 621-629. https://doi.org/10.1016/j.cej.2017.10.006
Kim J H, Mirzaei A, Hyoun W (2018) Novel superamphiphobic surfaces based on micro-nano hierarchical fluorinated Ag/SiO₂ structures. App Surf Sci 445: 262–271. https://doi.org/10.1016/j.apsusc.2018.03.148
Ma W, Higaki Y J, Takahara A (2017) Superamphiphobic coatings from combination of a biomimetic catechol-bearing fluoropolymer and halloysite nanotubes. Adv Mater Interfaces 4: 1700907. https://doi.org/10.1002/admi.201700907
Wang W J, Liu R P, Chi H J, Zhang T, Xu Z G, Zhao Y (2019) Durable superamphiphobic and photocatalytic fabrics: tackling the loss of super-non-wettability due to surface organic contamination. ACS Appl Mater Inter 11: 35327-35332. https://doi.org/10.1021/acsami.9b12141
Zuo H, Chen L, Kong M, Qiu L P, Wu P, Yang Y H, Chen K P (2018) Toxic effects of fluoride on organisms. Life Sci 198:18-24. https://doi.org/10.1016/j.lfs.2018.02.001
Martin J W, Mabury S A, Solomon K R (2003) Bioconcentration and tissue distribution of perfluorinated acids in rainbow trout (oncorhynchus mykiss). Environ Toxicol Chem 22: 196-204.
Martin J W, Mabury S A, Solomon K R, Muir DCG (2003) Dietary accumulation of perfluorinated acids in juvenile rainbow trout (Oncorhynchus mykiss). Environ Toxicol Chem 22:189-195.
Cao C Y, Ge M Z, Huang J Y, Li S H, Deng S, Zhang S N, Chen Z, Zhang K Q, Al-Deyab S S, Lai Y K (2016) Robust fluorine-free superhydrophobic [email protected] for highly effective self-cleaning and efficient oil-water separation. J Mater Chem A 4:12179-12187. https://doi.org/10.1039/c6ta04420d
Zheng L Z, Su X J, X.J. Lai, W.J. Chen, H.Q. Li, X.R. Zeng (2019) Conductive superhydrophobic cotton fabrics via layer-by-layer assembly of carbon nanotubes for oil-water separation and human motion detection. Mater Lett 253: 230-233. https://doi.org/10.1016/j.matlet.2019.06.078
Lin M, Parida K, Cheng X (2017) Flexible superamphiphobic film for water energy harvesting. Adv Mater Technol-us 2: 1600186. https://doi.org/10.1002/admt.201600186
Jin G W, Kim J Y, Min B G (2018) Superhydrophobic and antibacterial properties of cotton fabrics treated with PVDF and nano-ZnO through phase inversion process. Fiber Polym 19: 1835–1842. https://doi.org/10.1007/s12221-018-8313-x
Wen B N, Peng S, Yang X J, Long M Y, Deng W S, Chen G Y, Chen J Q, Deng W L (2017) A Cycle‐Etching Approach Toward the Fabrication of Superamphiphobic Stainless Steel Surfaces with Excellent Anticorrosion Properties. Adv Eng Mater 19: 1600879. https://doi.org/10.1002/adem.201600879
Kim M, Kim K, Lee N Y, Shin K, Kim Y S (2007) A simple fabrication route to a highly transparent superhydrophobic surface with a poly(dimethylsiloxane) coated flexible mold. Chem Commun 22:2237-2239. https://doi.org/10.1039/b618123f
Jin M, Feng X, Feng L, Sun T, Zhai J, Li T, Jiang L (2005) Superhydrophobic Aligned Polystyrene Nanotube Films with High Adhesive Force. Adva Mater 17: 1977-1981. https://doi.org/10.1002/adma.200401726
Zhang J P, Gao Z Q, Li L X, Li B C, Sun H X (2017) Waterborne Nonfluorinated Superhydrophobic Coatings with Exceptional Mechanical Durability Based on Natural Nanorods. Adv Mater Interfaces 4: 1700723. https://doi.org/10.1002/admi.201700723
Qu M N, Ma X R, Hou L G, Yuan M J, He J, Xue M H, Liu X G, He J M. Fabrication of Durable Superamphiphobic Materials on Various Substrates with Wear-Resistance and Self-Cleaning Performance from Kaolin. Appl Surf Sci 456: 737-750. https://doi.org/10.1016/j.apsusc.2018.06.194
Ma W, Wu H, Higaki Y J, Takahara A (2018) Halloysite Nanotubes: Green Nanomaterial for Functional Organic‐Inorganic Nanohybrids. Chem Rec 18: 986-999. https://doi.org/10.1002/tcr.201700093
Liu X R, Wang K L, Zhang W, Zhang J P, Li J Z (2019) Robust, self-cleaning, anti-fouling, superamphiphobic soy protein isolate composite films using spray-coating technique with fluorinated HNTs/SiO₂. Compos Part B-Eng 174: 107002. https://doi.org/10.1016/j.compositesb.2019.107002
Yang M P, Liu W Q, Jiang C, Xie Y K, Shi H Y, Zhang F Y, Wang Z F (2019) Facile construction of robust superhydrophobic cotton textiles for effective UV protection, self-cleaning and oil-water separation. Colloids Surfaces A 570:172-181. https://doi.org/10.1016/j.colsurfa.2019.03.024
Yang M P, Jiang C, Liu W Q, Liang L Y, Pi K (2019) A less harmful system of preparing robust fabrics for integrated self-cleaning, oil-water separation and water purification. Environ Pollut 255:113277. https://doi.org/10.1016/j.envpol.2019.113277
Cheng Z L, Sun W (2015) Preparation of N-doped ZnO-loaded halloysite nanotubes catalysts with high solar-light photocatalytic activity. Water Sci Technol 72: 1817–1823. https://doi.org/10.2166/wst.2015.403
Wu L, Zhang J P, Li B C (2013) Mimic nature, beyond nature: facile synthesis of durable superhydrophobic textiles using organosilanes. J Mater Chem B 1:4756–4763. https://doi.org/10.1039/c3tb20934b
Zhang J P, Li B C, Wu L, Wang A Q (2013) Facile preparation of durable and robust superhydrophobic textiles by dip coating in nanocomposite solution of organosilanes. Chem Commun 49: 11509-11511. https://doi.org/10.1039/c3cc43238f
Momen G, Farzaneh M (2012) A ZnO-based nanocomposite coating with ultra-water repellent properties. Appl Surf Sci 258:5723-5728. https://doi.org/10.1016/j.apsusc.2012.02.074

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Robust ZnO/HNTs-Based Superhydrophobic Cotton Fabrics With UV Shielding, Self-Cleaning, Photocatalysis, and Oil/Water Separation

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Journal Publication

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Abstract

Figures

1. Introduction

2. Experimental

3. Results And Discussion

3.1 Preparation of ZnO/HNTs and ZnO/HNTs/[email protected]

3.2 Characterization of ZnO/HNTs and superhydrophobic cotton fabrics

3.3 Wettability of superhydrophobic cotton fabrics

3.4 Durability evaluation of the superhydrophobic cotton fabrics

3.5 Self-cleaning antifouling performance

3.6 Photocatalytic performance

3.7 Oil-water separation of the superhydrophobic cotton fabrics

3.8 UV-shielding property of the superhydrophobic cotton fabrics

4. Conclusion

Declarations

Acknowledgements

References

Status:

Journal Publication

Version 1