Work

Unit-Cell Molecular Dynamics Framework for Cross-Linked Hydrogels: Linking Cross-Link Density, Hydration Shells, and Swelling

Year: 2026

Type: preprint

Abstract: Rational design of polyacrylamide (PAAm) hydrogels involves linking local amide–water interactions to macroscopic properties. This study combines molecular dynamics (MD) simulations of “unit-cell” PAAm segments with experimental data to explore how the acrylamide (Ac) to N,N′ methylenebisacrylamide (BAc) molar ratio affects network structure and water dynamics. By modeling PAAm chains at ratios from 4:1 to 7:1, we reframe a covalently cross-linked network using a non-covalently self-assembling unitcell analogy, bridging oligomer-proxy and supramolecular modeling paradigms. Validating our findings against gravimetric swelling, FTIR, SEM, and oscillatory rheology data, we identify a two-stage assembly mechanism. Initially, amide groups undergo intrasegment electrostatic pre-organization, followed by inter-segment hydrogen-bonding.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15008483/v1

Authors: Miteshkumar Moirangthem, Tanu Tiwari, Karthik Pushpavanam, Santosh Kumar Meena

Institutions: Indian Institute of Technology Ropar, Indian Institute of Technology Gandhinagar

Language: English

Topic: Hydrogels: synthesis, properties, applications

Subfield: Biomaterials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: Arthritis National Research Foundation, National Research Foundation, Department of Science and Technology, Ministry of Science and Technology, India, Indian Institute of Technology Ropar, Science and Engineering Research Board

Awards: G1062786212, G6625085623, G7330633165

OpenAlex ID: W7211933719

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