Superhydrophobic Fabric Based On Polydopamine And Its Stability

With the developing of technology and advancing of people’ living quality, people require more functionalities for the fabric, not only keeping warm and comfortable but also self-cleaning, anti-bacterial, and so on. Surface modification is helpful to improve the performance of fabric and meet the requirements of people for fabric. In recent years,as a kind of functional fabric, superhydrophobic fabric（SF） has received the widespread attention, and some methods have been developed to fabricate the SF. However, these methods still exist some defects, which limit the practical application of SF in the daily life. For example, the preparation is generally performed in harsh conditions and the stability of the so-obtained SF is not good.In this thesis, a method based on polydopamine（PDA） has been proposed to fabricate the SF. PDA served as “double faced adhesive” firmly sticking to the polyethylterephalate（PET） fabric and inducing the deposition of silver oxide nanoparticles（Ag₂O NPs）, which were further modified by 1H, 1H, 2H, 2H-perfluorodecanethiol（PFDT）. In this condition, the inter-layer interaction is supposed to be strong and the stability of the so-obtained SF is enhanced. This method is simple and universal. The main research contents are as follows:（1） Surface wettability. SF has been fabricated via the sequential deposition of PDA,Ag₂ O, and PFDT. The static contact angle and sliding angle on the SF are 162.4 ±2.5 ° and 3.2 ± 0.4 °, respectively. The surface morphologies and compositions are characterized by field emission scanning electron microscopy（FE-SEM） and X-ray photoelectron spectroscopy（XPS）, respectively. The results show that the surface of SF is composed of multi-scale Ag₂ O particles and PFDT, the former has increased the surface roughness and the latter has lowered the surface energy.（2） Stability. The stability of the SF is assessed by a series of tests. The results show that the SF possesses excellent chemical resistance, wear resistance, and washing resistance. Specifically, after immersing into aqueous solution with different p H values（such as the hydrochloric acid solution with a p H value of 1, the sodium chloride solution with a p H value of 7, and the sodium hydroxide solution with a p H value of 14） for 7 days, the contact angles on the SF are all above 150 °. The chemical resistance is mainly because that the SF is waterproof and the surfacemicro-structures and low-surface-energy compositions will not be destroyed by the corrosive species in the solution. After dry friction test for 100 cycles, the contact angles on the SF remain above 150 °. After accelerate washing test for 30 cycles（equal to 150 cycles of home washing）, the contact angles on the SF remain above150 °. The excellent stability of the SF is probably attributed to the strong inter-layer interaction.（3） Anti-bacterial property. The antibacterial activity of the SF is evaluated against Staphylococcus aureus（Gram-positive） and Klebsiella pneumoniae（Gram-negative）. The results show that the reduction rate of bacterial is above99.99 %, and the antibacterial activity is above 2.0. This excellent anti-bacterial property is due to the weak bacterial attachment for the low protein adsorption and easy protein attachment and the release of silver ions, which can kill bacteria.