Stimuli-responsive copolymers of n-isopropyl acrylamide with enhanced longevity in water for micro- and nanofluidics, drug delivery and non-woven applications

The aim of this study is in radical copolymerization of stimuli-responsive poly(methyl methacrylate/N-isopropyl acrylamide) [P(MMA/NIPAM)] and poly(methyl methacrylate/N-isopropyl acrylamide/acrylic acid) [P(MMA/NIPAM/AAc)] copolymers with an enhanced longevity in aqueous surroundings. [P(MMA/NIPAM)] copolymers are shown to be thermo-responsive, whereas [P(MMA/NIPAM/AAc)] copolymers are shown to be pH-responsive. Such copolymers of NIPAM and MMA or NIPAM, MMA and AAc are synthesized as random polymers, where all monomer units are randomly arranged along the polymer backbone (or as comb-like polymers) and connected by covalent bonds. In distinction from the traditional copolymers based on NIPAM, the copolymers synthesized in the present work possess covalent bonds connecting all the monomers, which enhances their stability in water. In addition, these novel copolymers have sufficiently high molecular weight, which allows for their processing via electrospinning. Non-woven materials of these novel copoloymers are of interest for such applications as micro- and nanofluidics, disposable wipers, drug carriers, and tissue engineering.