Fabrication of stable biomimetic coating on PDMS surface: Cooperativity of multivalent interactions

• Published in: Applied surface science 2019-03, Vol.469, p.720-730
• Main Authors: Zhao, Yang, Wen, Jialun, Ge, Ying, Zhang, Xiting, Shi, Huan, Yang, Kewu, Gao, Xiang, Shi, Suqing, Gong, Yongkuan
• Format: Article
• Language: English
• Subjects: Biomimetic coating; Cooperativity; Multivalent zwitterionic copolymer; PDMS
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.11.056

[Display omitted] •A kind of multivalent zwitterionic poly(methacrylate) copolymers (PMGT) containing epoxy and –Si–(OCH3)3 ligands were designed and synthesized.•The molar ratio of epoxy and –Si–(OCH3)3 (ne/nSi) plays a crucial role in the regulation of the coating formation.•Lower ne/nSi is helpful to produce a more uniform and dense biomimetic coating on PDMS surface and achieve controllable surface properties. A series of multivalent zwitterionic poly(methacrylate) copolymers (PMGT) containing different reactive ligands (epoxy and –Si–OCH3) are designed and synthesized for surface modification of 3-aminopropyltriethoxysilane activated PDMS (PDMS-A) via a simple incubation and subsequent post-crosslinking procedure. The co-existence of protonated primary amine (NH3+), terminal primary amine (−NH2) and Si–OH/Si–OC2H5 surface receptors on PDMS-A created a platform to fabricate stable PMGT coatings through multivalent interactions with epoxy and –Si–OCH3 ligands in the polymer chains. The effect of molar ratio of epoxy and –Si–(OCH3)3 ligands (ne/nSi) in the polymer chains on the cooperativity of multivalent interactions is studied. The results show that ne/nSi in the PMGT polymer chain plays a crucial role in the regulation of the coating formation. At higher ne/nSi (1.78), a relatively rough and thin biomimetic coating is formed. By contrast, lower ne/nSi (1.04) in the polymer chain is helpful to produce a more uniform and dense polymer coating. It is attributed to the good balance between the anchoring of polymer chains and the growth of coating thickness in the incubation step through suppressing the competitive autocatalytic crosslinking reactions of epoxy-amine system, demonstrating positive cooperativity of multivalent interactions. The following post-crosslinking procedure under moisture atmosphere containing triethylamine (TEA) facilitates to realize the formation of durable PMGT polymer coating, in which zwitterionic PC moieties are orientated towards the outer surface, providing the PDMS with greatly improved controllable hydrophilicity, coating stability and antifouling properties.