pH-responsive amphiphilic copolymers based on N-vinylpyrrolidone and fluoroacrylates with different structures: synthesis via RAFT process and surface properties

The copolymerization of 1,1,1,3,3,3-hexafluoroisopropylacrylate (HFIPA) and 2,2,3,3,4,4,5,5-octafluoropentyl acrylate (OFPA) with N-vinylpyrrolidone (NVP) in the presence of S,S’-dibenzyl trithiocarbonate (BTC) and polymeric RAFT agents based on fluoroacrylates were investigated. The copolymerization process proceeds in a control mode at any conditions investigated that was confirmed by the first order of reaction by monomer and SEC curves. Reactivity ratios of monomers were determined by the Fineman-Ross and Kelen-Tudos models. Aggregation behavior of copolymers at the air/water interface was studied by the Langmuir film balance technique. The influence of the composition and pH of the subphase on the surface properties of copolymers is considered. With the rise of subphase pH, as well as an increase in the mole fraction of NVP in the copolymer, the pressure of the plateau formation process increases. The morphology of LB films of various compositions was studied by atomic force microscopy. With the elevation in the proportion of NVP, a change in the size of micelles is traced.