Preparation of thermoresponsive poly(N-vinylcaprolactam-co-2-methoxyethyl acrylate) nanogels via inverse miniemulsion polymerization

Stimuli-responsive polymeric nanogels hold great potential in biological applications. In this work, thermoresponsive polymeric nanogels were conveniently prepared through inverse miniemulsion polymerization of two monomers with a good biocompatibility, N -vinylcaprolactam and 2-methoxyethyl acrylate. A macromolecular crosslinker, poly(ethylene glycol) dimethacrylate (PEGDMA), was used to achieve a better thermoresponsiveness, compared with low-molecular-weight crosslinkers. The prepared poly( N -vinylcaprolactam- co -2-methoxyethyl acrylate) (poly(NVCL- co -MEA)) nanogels could be well redispersed in aqueous systems, displaying a reversible thermoresponsive transition behavior. The influences of the synthesis parameters including the emulsifier content, PEGDMA content, and monomer composition on the particle properties of poly(NVCL- co -MEA) nanogels both in inverse emulsions and in aqueous dispersions were systematically investigated. Furthermore, the impacts of the monomer composition and PEGDMA content on the thermoresponsiveness of poly(NVCL- co -MEA) nanogels were also studied. Promisingly, the introduction of MEA monomeric units to the copolymer chains only slightly reduced the thermoresponsiveness of poly(NVCL- co -MEA) nanogels. This feature allows to improve the biocompatibility of polymeric nanogels by using MEA as the comonomer without need to compromise the thermoresponsiveness of nanogels. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48237.