mz6b00830_si_001.pdf (411.92 kB)
pH-Tunable Thermoresponsive PEO-Based Functional Polymers with Pendant Amine Groups
journal contribution
posted on 2016-12-02, 20:19 authored by Joonhee Lee, Alaina J. McGrath, Craig J. Hawker, Byeong-Su KimThermoresponsive
polymers exhibiting lower critical solution temperatures
(LCSTs) in aqueous solution have garnered considerable attention for
the development of smart materials. Herein, we report the synthesis
and properties of pH-tunable thermoresponsive poly(ethylene oxide)
(PEO)-based functional polymers bearing pendant amine groups with
varying cloud points. Well-defined poly(ethylene oxide-co-allyl glycidyl ether) (P(EO-co-AGE)) copolymers
were prepared via controlled anionic ring-opening copolymerization
of ethylene oxide (EO) with 10 mol % of a functional allyl glycidyl
ether (AGE) comonomer. Facile, modular thiol–ene click chemistry
was then employed to introduce a library of different aminothiols
as side chains to the initial P(EO-co-AGE) copolymer.
Depending on the nature of the pendant amine groups (primary amine,
dimethylamine, and diethylamine) and the hydrophobicity of the side
chains (ethyl, propyl, and hexyl), the cloud points could be tuned
from 44–100 °C under different pH conditions. This is
the first systematic investigation into the effect of PEO copolymer
side chains on cloud point, which opens up the opportunity to make
new thermoresponsive polymers for a variety of smart material applications.