Self-Healing and Mechanical Properties of Predesigned Supramolecular Polyampholyte Hydrogels

Abstract

The polyampholyte (PA) hydrogels were successfully synthesized by thermal-polymerization method Polyampholytes are composed of randomly dispersed cationic and anionic repeating groups The physical cross-linking of ionic side-chains gives the hydrogels self-healing and strong mechanical properties In this study N N’-methylenebis(acrylamide) (Bis-Am) is served as chemical cross-linker to enhance the mechanical property of hydrogels 2-hydroxyethyl methacrylate (HEMA) containing hydroxyl group is incorporated to improve water content Introducing of non-ionic units changes supramolecular construction and significantly affects the properties of the fabricated gels The results showed the hydrogels cross-linked with Bis-Am exhibiting strong mechanical property but losing water content simultaneously The results suggest that chemical cross-linker hold the polymer network more tightly and made the hydrogel rigid but offered less space for water storage In contrast to Bis-Am HEMA indeed helped to absorb more water but caused the hydrogels weak due to incapability of joining ion-pair cross-linking system By introducing such agents the Young’s modulus was promoted from 0 4 to 2 4 MPa and the water content was boosted from 62% to 73% With proper molar ratio of ionic groups the PA hydrogels showed great self-healing performance Adding of excess non-ionic agents interrupted the re-forming of ionic side chains led to fail in self-healing In this study a simple approach to adjust the properties of PA hydrogels was developed

Date of Award	2017 Jul 19
Original language	English
Supervisor	Jui-Hsiang Liu (Supervisor)