Chemistry Project Abstract
THE EFFECT OF SYSTEM PARAMETERS ON THE PRE-TRANSITION SWELLING OF CHARGED HYDROGELS
Presenters:
Kevin Patel, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506; kpatel18@imsa.edu
David Qasem, Illinois Mathematics and Science Academy, 1500 West Sullivan Road, Aurora, IL, 60506; dqasem@imsa.edu
Mentors:
Dr. Nily R. Dan, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104; 215-895-6624; dan@coe.drexel.edu
Dr. Anthony Lowman, Drexel University, College of Engineering, 3141 Chestnut Street, Philadelphia, PA, 19104; 215-865-2228; alowman@drexel.edu
Abstract:
We investigate the effects of pH, sub-chain length and suspension salt concentration on the pre-transition swelling of charged poly methacrylic acid (PMAA) hydrogels. We see that if no salt is added to the solution, the degree of swelling is set by the balance between the sub-chain stretching and the degree of charge dissociation. As a result, gels composed of longer subchains are significantly more swollen than their short-chain counterparts. However, when salt is added this trend may reverse, so that short sub-chain hydrogels are more swollen than the long-chain ones. This is due to the fact that salt plays a dual role: Increasing the charge degree of dissociation, but decreasing the range of electrostatic interactions