Molecular Dynamics Calculations for the Temperature Response of Poly(alkylated tri(ethylene oxide)isocyanate) Aqueous Solution

Aqueous solutions of conventional temperature-responsive amphiphilic polymers undergo a coil–globule conformational transition around the lower critical solution temperature (LCST) that causes the polymer surfaces to become hydrophobic and the polymers to aggregate together. Isocyanate polymers with...

Full description

Saved in:
Bibliographic Details
Published in:Macromol 2023-09, Vol.3 (3), p.653-664
Main Authors: Mizutani, Shunsuke, Kita, Shunya, Sakai, Naoya, Yamamoto, Takuya, Koleżyński, Andrej, Kakuchi, Toyoji, Sato, Shin-ichiro
Format: Article
Language:English
Subjects:
Aqueous solutions
Atoms & subatomic particles
Hydration
Hydrogen bonds
Neutrons
NMR
Nuclear magnetic resonance
Phase transitions
polyisocyanate
Polymerization
Polymers
rod polymer
Simulation
Solvents
Temperature
temperature responsive polymer
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Aqueous solutions of conventional temperature-responsive amphiphilic polymers undergo a coil–globule conformational transition around the lower critical solution temperature (LCST) that causes the polymer surfaces to become hydrophobic and the polymers to aggregate together. Isocyanate polymers with alkylated oligo(ethylene oxide) side chains are expected to have rigid main chains and, thus, do not undergo the coil–globule structural transition, but they have recently been reported to exhibit temperature-responsive properties. In this study, molecular dynamics was used to calculate the agglomeration tendencies of two chains of poly(alkylated tri(ethylene oxide)isocyanate) (PRTEOIC, where R = methyl (Me) or ethyl (Et)) in aqueous solution to elucidate the LCST phenomenon in the absence of coil–globule conformational transition. Our MD simulations showed that aggregation also occurs in rod polymers. Furthermore, we found that both (PMeTEOIC)2 and (PEtTEOIC)2 showed parallel agglomeration of the two molecular chains with increasing temperature, but only (PMeTEOIC)2 showed a metastable T-shaped agglomeration in the middle temperature range. The crossing-point temperature (TCRP) at which the density of the first hydrophobic hydration shell around the sidechain alkyl group equals the bulk water density is a useful indicator for predicting the LCST of rod polymers with dense side chains terminated by alkyl groups.
ISSN:2673-6209
2673-6209
DOI:10.3390/macromol3030036