Synthesis and solution properties of a temperature-responsive PNIPAM–b-PDMS–b-PNIPAM triblock copolymer

Cook, M. T., Filippov, S. K. and Khutoryanskiy, V. V. ORCID: https://orcid.org/0000-0002-7221-2630 (2017) Synthesis and solution properties of a temperature-responsive PNIPAM–b-PDMS–b-PNIPAM triblock copolymer. Colloid and Polymer Science, 295 (8). pp. 1351-1358. ISSN 0303-402X doi: 10.1007/s00396-017-4084-y

Abstract/Summary

In this paper, we report the synthesis and self-assembly of a novel thermoresponsive PNIPAM60–b-PDMS70–b-PNIPAM60 triblock copolymer in aqueous solution. The copolymer used a commercially available precursor modified with an atom transfer radical polymerization (ATRP) initiator to produce an ABA triblock copolymer via ATRP. Small-angle neutron scattering (SANS) was used to shed light on the structures of nanoparticles formed in aqueous solutions of this copolymer at two temperatures, 25 and 40 °C. The poly(dimethylsiloxane) block is very hydrophobic and poly(N-isopropylacrylamide) (PNIPAM) is thermoresponsive. SANS data at 25 °C indicates that the solutions of PNIPAM–b-PDMS–b-PNIPAM copolymers form well-defined aggregates with presumably core–shell structures below cloud point temperature. The scattering curves originating from nanoparticles formed at 40 °C in 100% D2O or 100% H2O were successfully fitted with the Beaucage model describing aggregates with hierarchical structure.