Synthesis of ABA-type double hydrophilic amphiphilic PU-based block copolymers of poly(N-Vinylpyrrolidone) and poly(N-isopropylacrylamide) via click chemistry

Abstract

Double hydrophilic ABA-type amphiphilic polyurethane (PU)-based poly(N-vinylpyrrolidone) (PNVP)-b-PU-b-PNVP and poly(N-isopropylacrylamide) (PNIPAM)-b-PU-b-PNIPAM triblock copolymers have successfully been synthesized via the combination of the step-growth polymerization, reversible addition-fragmentation chain transfer (RAFT) polymerization and azide-alkyne click reaction. All polymers are characterized by ¹H NMR, FTIR, and gel permeation chromatography. The cmcs of PNVP-b-PU-b-PNVP block copolymers increase with increase in PNVP block length: 0.0019 mg/mL for PNVP₃₉-b-PU-b-PNVP₃₉ and 0.005 mg/mL for PNVP₆₈-b-PU-b-PNVP₆₈. The iron-chelating ability and the reducing power of PNVP₆₈-b-PU-b-PNVP₆₈ are superior to that of PNVP owing to the presence of urethane moiety of PU block in copolymer. The LCST of PNIPAM-b-PU-b-PNIPAM are lower than that of PNIPAM (33 °C): 23.5 and 25.5 °C for PNIPAM₄₂-b-PU-b-PNIPAM₄₂ and PNIPAM₆₆-b-PU-b-PNIPAM₆₆, respectively.

Graphical Abstract

KEYWORDS:

• PNVP-b-PU-b-PNVP
• PNIPAM-b-PU-b-PNIPAM
• click reaction

Additional information

Funding

BR acknowledges the financial supports from the Department of Science and Technology, Government of India, through grant no. SR/S1/PC-25/2006 and the Council of Scientific and Industrial Research, Government of India, through Grant no. 02(0002)/11/EMR-II. VKP, NKV and AKM acknowledge CSIR, Government of India for the Research Fellowships.