Functionalization of PET fabric via silicone based organic–inorganic hybrid coating
Introduction
With the improvement of people’s living standards, the requirements for textile materials are not limited to styles and materials, but also required its functionality. Functionalization of fabrics has become a hot topic of current research, such as fabric acting as a biosensor for colorimetric recognition of urea [1], fabric coated by luminescent composite with antimicrobial activity and ultraviolet protection [2], fabric with water repellent and flame retardant [3], carbon-nanotube fibers for wearable devices [4], smart textiles [5], technical textiles [6], and biomimetics textiles [7]. Nano-technology plays an important role in textile functionality such as water repellency and self-cleaning property. Ibrahim et al. [8] studied multifunctionalization of cellulose-containing fabrics through added Ag or TiO2 nanoparticles, the finished fabrics demonstrated a remarkable improvement in their self-cleaning capacity. In addition, Fahmy et al. [9] founded that Ag and TiO2 nanoparticles were incorporated as functional additives to enhance the self-cleaning performance of treated viscose fabrics.
Inspired by water repelling and self-cleaning properties of the lotus leaf, artificial hydrophobic surfaces have attracted extensive interest in academic and industrial areas [10], [11], [12], [13]. It is well known that a hydrophobic surface generally has low surface energy and particular roughness [14], [15]. Textiles are composed of fibers with microscale structure and low surface energy layers, and the application of further nanoscale coatings is needed for their transformation into hydrophobic surfaces. Following this principle, numerous hydrophobic textile fabrics have been prepared by various methods, such as phase inversion [16], [17], surface polymerization [18], [19], and electrospinning method [20]. However, most of these techniques have disadvantages such as being time-consuming, using expensive and toxic fluorine-containing reagents, and showing low mechanical stability of hydrophobic fabrics, which limit their practical applications. Textiles are easily wetted and contaminated, and stains on the surface of fabrics are difficult to remove [21]. The cleaning of the stain consumes a large amount of water and detergent, which will produce waste water and pollution to the environment. It is very important to produce functional fabrics with stable self-cleaning and environmentally friendly properties [22], [23], [24].
In recent years, surface modification with organic–inorganic hybrid materials has attracted considerable attention [25], [26]. The organic materials of alkylsilanes and silicon can be used to modify materials to obtain excellent hydrophobic properties, and inorganic components such as SiO2 can provide better thermal stability, strength, surface roughness and oxidation resistance for hybrid polymers. However, the SiO2 particles easily agglomerate which restricts their application. Hence, it is necessary to modify the surface of SiO2 particles to expand their application [27], [28]. In addition, some special active functional groups can be introduced to improve the compatibility between SiO2 nanoparticles and other substances. SiO2 is easily modified with silane and used for the coating of textile surfaces by the introduction of hydrophobic ingredients, which will improve the water-repellent ability, and further achieve the self-cleaning effect.
The hydrophobic property can be characterized by measuring the water contact angle. However, for many soft porous materials such as cotton and silk, it is difficult to identify hydrophobicity using water contact angles since water droplets may be trapped in the concave structures, making the necessary contact line to define the contact angle unobtainable. The water impact behavior is a comprehensive method to characterize the surface wettability of hydrophobic soft porous materials [29]. Crick et al. [30] studied the relationship between water contact angle and the number of water bounces on superhydrophobic polymers, which provided a universal indication of surface superhydrophobicity and avoided the potential disparity in measuring the static water contact angle. The impact of droplets is followed by spreading, receding, or bouncing which all depend on the impact viscosity, surface tension, density and radius of the droplets and the properties of the surface [31]. To further expand the application of hydrophobic textiles, the morphology variation, spreading diameter, energy conversion and adhesion of the droplets impact behavior need to be investigated.
In this study, we reported an environmentally friendly and fluorine-free method to fabricate the hydrophobic PET textiles. Organic–inorganic hybrid materials composed of n-octadecyltriethoxysilane (OD) modified silica nanoparticles (OD-SiO2) were prepared via a modified Stöber method [32]. The OD-SiO2 nano hybrid materials were coated onto the surface of PET textiles via a conventional “dipping–drying” approach with the help of triethylamine (Et3N) and toluene. The hydrophobic fabrics features such as water contact angle (CA), water droplet impact behavior, rubbing and washing durability, mechanical and chemical stability, and self-cleaning property were measured.
Section snippets
Materials
PET fabrics (76 × 68, 100 g/m2) were purchased from Wujiang Zhongpeng Textile Co., Ltd. (Jiangsu, China). Tetraethoxysilane (TEOS), n-octadecyltriethoxysilane (ODTES) were obtained from Shanghai Aladdin biochemical technology Co., Ltd. (Shanghai, China). Toluene, anhydrous ethanol, triethylamine (Et3N), hydrochloric acid, sodium hydroxide and ammonium hydroxide were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). ANOSET® Yellow 4GN was provided from Shanghai Anoky Group Co.,
Characterization of OD-SiO2
As the hydrolysis rate of TEOS was relatively higher than that of ODTES, the reaction proceeds in stepwise fashion. TEOS was hydrolyzed and condensed first to form SiO2 in ethanol and deionized water solution with ammonium hydroxide as the catalyst. In this process, ODTES was subsequently hydrolyzed and co-condensed on the SiO2 surface, which indicated that the ODTES was located on the surface of SiO2. ODTES and TEOS gradually co-condensed to form OD-SiO2 nanocomposite [16]. There were two main
Conclusions
We successfully fabricated durable and robust hydrophobic self-cleaning PET fabric by coating with fluoro-free organic–inorganic OD-SiO2 hybrid materials. Compared with the pristine PET fabric, the surface of the coated PET fabric showed a double-layered coarse structure of micro/nano spherical particles and fibers. The coated PET fabric presented hydrophobic properties with an average water contact angle of 141°. In the water droplet impact experiment, it could be demonstrated that the coated
Conflict of interest
The authors declare that they have no conflict of interest.
Acknowledgments
This work is supported by the Natural Science Foundation of Jiangsu Province (Grants No. BK20180588) and the Fundamental Research Funds for the Central Universities (Grant No. JUSRP11702). Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No. KYCX19_1853).
References (47)
- et al.
React. Funct. Polym.
(2019) - et al.
Carbohydr. Polym.
(2013) - et al.
Mater. Lett.
(2016) - et al.
Cellulose
(2014) - et al.
J. Colloid. Interface Sci.
(2005) - et al.
J. Colloid. Interface Sci.
(1988) - et al.
J. Colloid. Interface Sci.
(2009) - et al.
J. Fluoresc.
(2019) - et al.
ChemistrySelect
(2019) - et al.
Adv. Mater.
(2016)