Tuning the low critical solution temperature of polymer brushes grafted on single-walled carbon nanotubes and temperature dependent loading and release properties

Abstract

A nondestructive method was developed for grafting and retrieving polymer brushes from single-walled carbon nanotubes (SWCNT)s based on mussel-inspired chemistry. Thermo-responsive polymer brushes were grafted on SWCNTs by coating the tubes with polydopamine as a reactive underlayer and sequential surface-initiated atom transfer radical polymerization of oligo(ethylene glycol) methacrylate (OEGMA, Mn = 475) and 2-(2'-methoxyethoxy)ethyl methacrylate (MEO2MA). Copolymer brushes were retrieved from the SWCNTs using 1 M NaOH to destroy the crosslinked polydopamine coating, and after that, the pristine properties of the SWCNTs were preserved. The low critical solution temperature (LCST) and molecular weight of the copolymer were measured using a nephelometer and gel permeation chromatograph, respectively. The loading and release behavior of Rhodamine 6G on responsive polymer-grafted SWCNTs demonstrates that the copolymer brushes confer the SWCNTs an LCST dependence. This method can accurately confirm the molecular weights and polydispersity of stimuli-responsive polymers grafted on any other nanoparticles and predict their controlled release behavior. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1807–1814