2 research outputs found
Hyperbranched Multiarm Copolymers with a UCST Phase Transition: Topological Effect and the Mechanism
A novel thermoresponsive
hyperbranched multiarm copolymer with
a hydrophobic hyperbranched polyÂ[3-ethyl-3-(hydroxymethyl)Âoxetane]
core and many polyÂ(acrylamide-<i>co</i>-acrylonitrile) (PÂ(AAm-<i>co</i>-AN)) arms was for the first time synthesized through
a reversible addition–fragmentation chain-transfer polymerization.
These copolymers show reversible, sharp, and controlled temperature-responsive
phase transitions at the upper critical solution temperature (UCST)
in water and electrolyte solution. It is the first report on the hyperbranched
copolymers with a UCST transition. Two series copolymers with variable
AN content (series A) and variable arm length (series B) were synthesized
to study the influence of molecular structure on the UCST transition.
It was found that the UCST of copolymers could be raised by increasing
the AN content or decreasing the arm length. Most interestingly, the
amplification effect of the hyperbranched topological structure leads
to a broad change of the UCST from 33.2 to 65.2 °C with the little
change of AN content (5.9%). On the basis of variable temperature
nuclear magnetic resonance, dynamic light scattering, and transmission
electron microscopy, a UCST transition mechanism, in combination with
hydrophilic/hydrophobic balance and multimicelle aggregate (MMA),
was proposed. This work enriches the UCST copolymer topology and may
extend the knowledge on the structure–activity relationship
as well as the mechanism of the UCST polymers
MOESM1 of Facile synthesis of N- (4-bromophenyl)-1- (3-bromothiophen-2-yl)methanimine derivatives via Suzuki cross-coupling reaction: their characterization and DFT studies
Additional file 1: Figure S1. HOMO, HOMO−1, HOMO−2, HOMO−3 and LUMO, LUMO+1, LUMO+2, LUMO+3 surfaces of 3b–3i