Synthesis of thermo-responsive polysiloxanes grafted by oligomeric ethylene oxide and their intelligent membranes

Abstract

Thermal responsive polymers, as a kind of smart materials that can undergo a reversible phase transition from soluble to insoluble status in water upon temperature change, have recevied a broad interests in various interesting fields, such as protein adsorption, tissue engineering and drug delivery. In recent years, lots of efforts were devoted to the synthesis of novel thermo-responsive ploymers with various kinds of amphiphilic structures. Due to its intrinsic hydrophobicity and biocompatibility, polysiloxane has been widely studied in thermo-responsive materials. In this study, thermo-responsive polysiloxanes containing oligomeric ethylene glycol (PMHS-OEG3) were successfully prepared by the highly efficient hydrosilylation reaction between polymethylhydrosiloxane (PMHS)and tri(ethylene glycol)allyl methyl ether with Karstedts catalyst. The PMHS-OEG3s were characterized by NMR, FTIR and UV-vis spectra. They showed the expected amphiphilic and thermoresponsive properties in an aqueous solution. Their Cloud Point (CP)decreased gradually with the increase of their degree of polymerization (DP)and could be tuned from 29.4℃ to 27.5℃. After cured with 1,3-divinyl-1, 1,3,3-tetramethyl disiloxane (MViMVi), the PMHS-OEG3s were crosslinked into smart thermo-responsive membranes and their inherent responsive character could also modulated by the DP of the PMHS-OEG3.