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pH-sensitivity of fast responsive superporous hydrogels
R A Gemeinhart1, J Chen, H Park
1Cornell University, School of Chemical Engineering, Ithaca, NY 14853-5201, USA.
Journal of Biomaterials Science. Polymer Edition
|March 23, 2001
Summary
Superporous hydrogels (SPHs) offer rapid swelling and shrinking responses, unlike traditional hydrogels. This fast-acting property, driven by capillary forces, enables new applications for stimuli-sensitive materials.
Area of Science:
- Materials Science
- Polymer Chemistry
- Chemical Engineering
Background:
- Stimuli-sensitive hydrogels exhibit slow swelling/shrinking due to water diffusion limitations.
- Traditional hydrogels require significant time for water penetration, limiting their responsiveness.
Purpose of the Study:
- To develop superporous hydrogels (SPHs) with significantly faster swelling and shrinking kinetics.
- To investigate the influence of environmental factors like pH and ionic strength on SPH behavior.
Main Methods:
- Synthesis of poly(acrylamide-co-acrylic acid) (p(AM-co-AA)) superporous hydrogels.
- Evaluation of swelling ratio in response to varying pH and ionic strength.
- Assessment of response time and reversibility of swelling/shrinking cycles.
Main Results:
- SPHs demonstrated swelling and shrinking rates orders of magnitude faster than conventional hydrogels.
- Swelling ratio was significantly influenced by pH and ionic strength, with pH having a pronounced effect.
- p(AM-co-AA) SPHs exhibited rapid, reversible swelling/shrinking upon alternating pH between 1.2 and 7.5.
Conclusions:
- Superporous hydrogels overcome the kinetic limitations of traditional stimuli-sensitive hydrogels.
- The rapid response of SPHs opens possibilities for applications requiring fast, reversible hydrogel actuation.
- SPHs are suitable for applications where single-piece hydrogels are preferred over microparticulates.