Superporous hydrogels: Synthesis and applications
Abstract
The purpose of this study was to synthesize a new type of material, superporous hydrogel, and to explore its potential applications. Superporous hydrogels have numerous supersize pores inside them, and the typical pore sizes are several hundred micrometers. These unique structures give them distinctive properties from the traditional non-porous hydrogels and the macroporous hydrogels (pore size of several micrometers). Superporous hydrogels were prepared by a gas blowing method. The crosslinking polymerization occurred when the foam was stabilized so that the pores were permanently captured in the polymer matrix. Various types of superporous hydrogels were synthesized in this study. Superporous hydrogels can be used in various applications. In this study, four applications were explored. The first one was to make fast swelling superabsorbents. In aqueous solution, superporous hydrogels swelled several times larger and hundreds of times faster than the conventional non-porous hydrogels. The key factors for the fast swelling were well connected capillary channels and good polymer surface wettability. Ethanol dehydration, moistening, wetting agent, and superdisintegrants all improved the swelling rate of superporous hydrogels. The second application was to make degradable superporous hydrogels. Sucrose based superporous hydrogels were synthesized and they showed several times faster degradation than the non-porous hydrogels. The third application of superporous hydrogels was in the controlled drug delivery. Gastric retentive superporous hydrogels were synthesized for sustained oral drug delivery. The dosage forms had a small dry size, a large swollen size, a fast swelling time, strong mechanical properties, and were retained in the stomach for up to 4.5 h in the fasted dog and up to 27 h in a dog that was fed in the first 6 h after the administration of the dosage form but was fasted thereafter. Factors attributed to the fast swelling and strong mechanical properties were studied. The fourth application was to make fast responsive thermo-reversible superporous hydrogels. They responded to the environmental temperature changes within 1∼2 min, while the non-porous hydrogels took hours.
Degree
Ph.D.
Advisors
Park, Purdue University.
Subject Area
Pharmaceuticals|Polymers|Chemical engineering
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