Recyclable L-Proline Functional Nanoreactors with Temperature-Tuned Activity Based on Core-Shell Nanogels

Research output: Contribution to journalLetterpeer-review

Authors

  • Annhelen Lu
  • Dafni Moatsou
  • Ian Hands-Portman
  • Deborah A. Longbottom
  • Rachel O'Reilly

Colleges, School and Institutes

Abstract

Recyclable core–shell (CS) nanogels based on l-proline-containing hydrophobic cores with a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) shell have been synthesized via a seeded precipitation polymerization process. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to verify the successful addition of the shell and investigate the thermoresponsive properties of the nanostructures. The catalytic activity of the nanogels was assessed in a model asymmetric aldol reaction, where an enhancement was observed with increasing temperature, attributed to the hydrophobic nature of the PNIPAM shell. However, when a nanogel was synthesized with core–shell morphology based on a gradient of cross-linking density in the corona (GS), a dramatic drop in activity was observed at elevated temperatures: the collapse of the outer, lightly cross-linked, “corona” polymer chains appears to block access to the catalytic core. High activity and enantioselectivity were maintained in a number of recovery and reuse cycles, highlighting the recycling potential of these catalytic nanostructures.

Details

Original languageEnglish
Pages (from-to)1235-1239
Number of pages5
JournalACS Macro Letters
Volume3
Issue number12
Early online date17 Nov 2014
Publication statusPublished - 16 Dec 2014