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Temperature-sensitive PVA/PNIPAAm semi-IPN hydrogels with enhanced responsive properties.

Abstract

A series of temperature-sensitive hydrogels of semi-interpenetrating polymeric networks (semi-IPN) composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly(vinyl alcohol) (PVA) were prepared by radical polymerization. The PNIPAAm networks were cross-linked by N,N'-methylenebisacrylamide in the presence of linear PVA. The reaction processes were investigated by rheometry using oscillatory deformation tests. It was found that gelations were very fast and the modulus reached equilibrium within about 12.5min. The prepared semi-IPN hydrogels were characterized for their morphologies and thermal behaviors by scanning electron microscopy and differential scanning calorimetry, respectively. The interior network structures of the semi-IPN matrix became more porous with increasing PVA. In comparison to the conventional PNIPAAm gel, the newly reported semi-IPN hydrogels exhibited the same lower critical solution temperature. Their swelling properties, such as temperature dependence of equilibrium swelling ratio, shrinking kinetics and reswelling kinetics in water, were also studied. Experimental data indicated that the shrinking and reswelling rates of the semi-IPN hydrogels were much faster than those of the conventional PNIPAAm hydrogels. With this novel approach, water absorption and response properties could be adjusted by tuning the feed ratio of NIPAAm and PVA. These fast responsive hydrogels exhibited improved temperature sensitivity and swelling properties compared to the conventional PNIPAAm hydrogel, which would be critical and desirable for a gel to find potential applications in biomedical fields, such as drug delivery systems and sensors.

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  • Authors+Show Affiliations

    ,

    Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University Jena, Lödergraben 32, D-07743 Jena, Germany.

    ,

    Source

    Acta biomaterialia 5:1 2009 Jan pg 488-97

    MeSH

    Acrylamides
    Acrylic Resins
    Animals
    Calorimetry, Differential Scanning
    Cell Survival
    Fibroblasts
    Hydrogels
    Kinetics
    Mice
    Microscopy, Electron, Scanning
    Oscillometry
    Polymers
    Polyvinyl Alcohol
    Rheology
    Temperature
    Time Factors

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    18656431