Independent characterization of the elastic and the mixing parts of hydrogel osmotic pressure

Fuente: arXiv
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Autori principali: Shao, Zefan, Liu, Qihan
Natura: Preprint
Pubblicazione: 2023
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author Shao, Zefan
Liu, Qihan
author_facet Shao, Zefan
Liu, Qihan
contents Osmotic pressure is the driving force for the swelling of hydrogels. The hydrogel osmotic pressure can be decomposed into two parts: the mixing part due to polymer-solvent interaction and the elastic part due to polymer chain stretching. While the two components are distinguished in existing constitutive models, they have not been independently characterized in experiments. This paper reports a novel method to independently measure these two components using a fully constrained swelling test. The test allows the crosslink density to be varied at a fixed polymer content, thus varying the elastic part independently of the mixing part. Our measurement shows that the widely used Flory-Rehner model predicts the mixing part accurately for polyacrylamide hydrogel of a wide range of swelling ratios but predicts the elastic part with orders-of-magnitude error.
format Preprint
id arxiv_https___arxiv_org_abs_2308_04533
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Independent characterization of the elastic and the mixing parts of hydrogel osmotic pressure
Shao, Zefan
Liu, Qihan
Soft Condensed Matter
Osmotic pressure is the driving force for the swelling of hydrogels. The hydrogel osmotic pressure can be decomposed into two parts: the mixing part due to polymer-solvent interaction and the elastic part due to polymer chain stretching. While the two components are distinguished in existing constitutive models, they have not been independently characterized in experiments. This paper reports a novel method to independently measure these two components using a fully constrained swelling test. The test allows the crosslink density to be varied at a fixed polymer content, thus varying the elastic part independently of the mixing part. Our measurement shows that the widely used Flory-Rehner model predicts the mixing part accurately for polyacrylamide hydrogel of a wide range of swelling ratios but predicts the elastic part with orders-of-magnitude error.
title Independent characterization of the elastic and the mixing parts of hydrogel osmotic pressure
topic Soft Condensed Matter
url https://arxiv.org/abs/2308.04533