title: Self-assembly behavior of a stimuli-responsive water-soluble [60]fullerene-containing polymer.
abstract: A novel pH- and temperature-responsive water-soluble [60]fullerene-containing poly[2-(dimethylamino)ethyl methacrylate] (C60-b-PDMAEMA) was synthesized by atom transfer radical polymerization. The pH and temperature dependence of the physical properties of the aqueous C60-b-PDMAEMA solution was studied by potentiometric and conductometric titrations, UV-vis transmittance, and laser light scattering techniques. At low pH and at temperatures ranging from 25 to 55 degrees C, in addition to C60-b-PDMAEMA unimers, micelle-like aggregates are produced in the aqueous solution containing C60 hydrophobic cores and protonated PDMAEMA shells. Only unimeric C60-b-PDMAEMAs are found to exist in solution at high pH and low temperature, where PDMAEMA segments form a charge-transfer complex with C60 molecules. However, C60-b-PDMAEMA precipitates from aqueous solution at temperatures exceeding the lower critical solution temperature of PDMAEMA of approximately 45 degrees C. The pH and temperature stimuli-responsive properties of the [60]fullerene-containing polymer in aqueous solution are completely reversible.
authors.affiliation: Singapore-MIT Alliance, Nanyang Technological University, 50 Nanyang Avenue, 639798, Republic of Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Dai
authors.forename: P
authors.initials: P
authors.lastname: Ravi
authors.forename: C H
authors.initials: CH
authors.lastname: Tan
authors.forename: K C
authors.initials: KC
authors.lastname: Tam