Aggregation Behavior of Doubly Thermoresponsive Polysulfobetaine-b-poly(N-isopropylacrylamide) Diblock Copolymers

• DOI: 10.1021/acs.macromol.6b01186
• Publication Date: 2016-08-16T17:03:51Z
• Authors: Natalya S. Vishne...; Viet Hildebrand; Bart-Jan Niebuur; Isabelle Grillo; Sergey K. Filippov; André Laschewsky; Peter Müller-Busc...; Christine M. Papa...
• Keywords: Poly(N-isopropylacrylamide); Cloud point

A 2-fold thermoresponsive diblock copolymer PSPP430-b-PNIPAM200 consisting of a zwitterionic polysulfobetaine (PSPP) block and nonionic poly(N-isopropylacrylamide) (PNIPAM) is prepared by successive RAFT polymerizations. In aqueous solution, the corresponding homopolymers PSPP PNIPAM feature both upper lower critical solution temperature (UCST LCST) behavior, respectively. The exhibits thermally induced “schizophrenic” aggregation behavior in solutions. Moreover, ion sensitivity cloud point to ionic strength nature salt offers possibility create switchable systems which respond sensitively changes electrolyte type concentration. solutions D2O are investigated means turbidimetry small-angle neutron scattering (SANS) with respect phase self-assembled structures dependence on content. Marked differences below UCST-type above LCST-type transition observed. addition small amount NaBr (0.004 M) does not affect overall only aggregate slightly altered, reflecting well-known block.