ИСТИНА

The amphiphilic semifluorinated block copolymers are very attractive for creating omniphobic coatings capable of self-cleaning from inorganic and organic contaminants. Fluorinated polymer blocks provide a low surface energy of the coating. Due to the presence of functional groups in hydrophilic polymer blocks, the copolymer covalently binds to the treated surface. The amphiphilic nature of block copolymers leads to microphase separation and thus provides micro- and/or nano-roughness of the coating surface. When wetting a low-energy nanorough surface with polar and non-polar liquids, the Cassi state is realized, which provides high contact angles (CA) and low CA hysteresis (CAH). The aim of this work was to synthesize amphiphilic diblock copolymers (DCs) of 2,3,4,5,6-pentafluorostyrene (PFS) and 2-hydroxyethyl methacrylate (HEMA) with different composition and molecular weight characteristics, and to investigate the effect of both fluorinated poly(2,3,4,5,6-pentafluorostyrene) (PPFS) and anchor poly(2-hydrpxyethyl methacrylate) (PHEMA) blocks of DCs on surface properties of the DC coatings applied on cotton/polyester fabric coatings based on DC [1-2]. The DCs of various composition with narrow MWD have been obtained by two-stage reversible addition-fragmentation chain transfer polymerization. The surface properties of fabric coatings based on DCs of various compositions have been investigated. It has been shown that the main factor determining the transformation of hydrophobic surfaces into superhydrophobic ones and ensuring the stabilization of the Cassi state is the ratio of lengths of PPFS and PHEMA blocks PnPFS/PnHEMA (Fig. 1). The increase in PnPFS/PnHEMA is accompanied by a significant increase in water (θН2О) and diiodomethane (θCH2I2) CA, which reach the plateau at PnPFS/PnHEMA = 3.5 and remains almost constant up to PnPFS/PnHEMA = 6.2. Surface modification of the cotton/polyester fabric with the DC having PnPFS/PnHEMA = 6.2 produced superhydrophobic surface with θН2О = 158 ± 4 º and CAH = 5 ± 2 °, and θCH2I2 = 107 ± 3 º. Fig.1. Dependence of θ^(H_2 O) (1) and θ^(〖CH〗_2 I_2 ) (2) of polyester cotton fabric coated with DC on the PnPFS/PnHEMA. So, superhydrophobic or even superamphiphobic properties were obtained at application of DC already with PnPFS/PnHEMA = 3.5. The work was financially supported by Russian Science Foundation (project № 17-13-01359-П) Referenses: Chekurov K.E., Barabanova A.I., Blagodatskikh I.V., Lokshin B.V., Peregudov A.S., Abramchuk S.S., Khokhlov A.R. Synthesis and self-assembling of amphiphilic diblock copolymers of 2,3,4,5,6-pentafluorostyrene // Dokl. Chem. 2019. V. 484. № 2. P. 33–36. Chekurov K.E., Barabanova A.I., Blagodatskikh I.V., Lokshin B.V., Kondratenko M.S., Gallyamov M.O., Peregudov A.S., Khokhlov A.R. Synthesis and Surface Properties of Amphiphilic Fluorine-containing Diblock Copolymers // J.Appl.Polym.Sci. – 2021. V. 138. – P. 49714.