Verification of scaling laws for degrading PLA-b-PEG-b-PLA hydrogels

✍ Scribed by Andrew T. Metters; Christopher N. Bowman; Kristi S. Anseth

• Book ID: 101431237
• Publisher: American Institute of Chemical Engineers
• Year: 2001
• Tongue: English
• Weight: 113 KB
• Volume: 47
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690470619

✦ Synopsis

Abstract

Several macroscopic properties of degrading poly(lactic acid)‐b‐poly(ethylene glycol)‐b‐poly(lactic acid) (PLA‐b‐PEG‐b‐PLA) hydrogels were compared to one another as functions of degradation time. The specific hydrogel properties measured were the compressive modulus (K), the volumetric swelling ratio (Q), and the normalized compressive modulus (K~NORM~ = KQ^1/3^). Their comparisons were used to evaluate the applicability of fundamental thermodynamic theories developed for nondegradable hydrogels on a degradable system. The equations predict scaling factors of −2, −5/3, and 6/5 for the dependence of K on Q, K~NORM~ on Q, and K on K~NORM~, respectively. These important experimental data for a degrading hydrogel system initially show good agreement with the scaling predictions. Further examination, however, reveals the scaling factors to change over the course of the degradation process. These changes are attributed, at least in part, to the changing chemical, mechanical, and ionic properties of the degrading copolymer networks.