Loading…

Effects of solvation shell relaxation on chain association mechanisms in poly(3-hexylthiophene) solutions

Using poly(3-hexylthiophene) (P3HT) as a model conjugated polymer and atomistic molecular dynamics simulations with carefully verified force fields, we performed in-depth investigations of solvation shell properties of P3HT chains (15 repeating units per chain) in two representative groups of non-po...

Full description

Saved in:
Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2021-05, Vol.23 (2), p.125-1214
Main Authors: Wu, Ching H, Hua, Chi C, Wang, Chun I
Format: Article
Language:English
Subjects:
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:Using poly(3-hexylthiophene) (P3HT) as a model conjugated polymer and atomistic molecular dynamics simulations with carefully verified force fields, we performed in-depth investigations of solvation shell properties of P3HT chains (15 repeating units per chain) in two representative groups of non-polar (or aprotic) organic solvents (better solvents: ortho -dichlorobenzene, bromobenzene, and chlorobenzene; poorer solvents: chloroform, para -xylene, and toluene). We demonstrated that solvation shell relaxation properties in P3HT solutions dictate the formation of regular π-π associations and, hence, crystallinity through the initial chain association and subsequent chain sliding. In contrast, the mean features of polymer-solvent interactions, including solvation free energy and radial distribution function, present little or no difference for all solvent media investigated. Better-solvent media were revealed to bear relatively large values of the first solvation shell relaxation time ( τ 1 > 100 ps) as well as larger ratios of relaxation times for the first two solvation shells ( τ 1 / τ 2 > 2), and vice versa for poorer-solvent media ( τ 1 < 100 ps and τ 1 / τ 2 < 2). The linear hexyl side-chain unit was noted to substantially enlarge both quantities while notably reducing the solvation free energy as well. As discussed herein, these findings shed new light on the mechanistic features by which solvent quality impacts the degree of π-π association crucial for modern applications with crystalline conjugated polymers. Solvation shell relaxations impact chain association and sliding and thus help determine the crystallinity and nanofiber formation in P3HT solutions.
ISSN:1463-9076
1463-9084
DOI:10.1039/d1cp00869b