Effect of Crosslinking Agent Concentration on the Properties of Unmedicated Hydrogels
Rachel Shet Hui Wong1, Mark Ashton2, Kalliopi Dodou3
1Department of Pharmacy Health and Wellbeing, Faculty of Applied Sciences, University of Sunderland, Science Complex, Wharncliffe Street, SR1 3SD Sunderland, UK. rachel.wong@research.sunderland.ac.uk.
Abstract:
Novel polyethylene oxide (PEO) hydrogel films were synthesized via UV crosslinking with varying concentrations of pentaerythritol tetra-acrylate (PETRA) as crosslinking agent. The aim was to study the effects of the crosslinking agent on the material properties of hydrogel films intended for dermatological applications. Fabricated film samples were characterized using swelling studies, scanning electron microscopy, tensile testing and rheometry. Films showed rapid swelling and high elasticity. The increase of PETRA concentration resulted in significant increase in the gel fraction and crosslinking density (ρc), while causing a significant decrease in the equilibrium water content (EWC), average molecular weight between crosslinks (\({\overline{M}}_{c}\)), and mesh size (ζ) of films. From the scanning electron microscopy, cross-linked PEO hydrogel network appeared as cross-linked mesh-like structure with interconnected micropores. Rheological studies showed PEO films required a minimum of 2.5% w/w PETRA to form stable viscoelastic solid gels. Preliminary studies concluded that a minimum of 2.5% w/w PETRA is required to yield films with desirable properties for skin application.
