The rubber elasticity of poly (N-isopropylacrylamide) hydrogel networks

We report here on the characterization of classical bulk poly (N-isopropylacrylamide) (PNIPAAm) hydrogel networks. The classical PNIPAAm hydrogels were prepared from N-isopropylacrylamide (NIPAAm) as a main monomer and N,N-methylenebisacrylamide (MBAAm) as a crosslinker. The viscoelastic character o...

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Bibliographic Details
Main Authors: Adrus, Nadia, Ulbricht, Mathias
Format: Article
Published: 2013
Subjects:
Online Access:http://eprints.utm.my/id/eprint/40838/
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Institution: Universiti Teknologi Malaysia
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Summary:We report here on the characterization of classical bulk poly (N-isopropylacrylamide) (PNIPAAm) hydrogel networks. The classical PNIPAAm hydrogels were prepared from N-isopropylacrylamide (NIPAAm) as a main monomer and N,N-methylenebisacrylamide (MBAAm) as a crosslinker. The viscoelastic character of bulk hydrogels was examined using rheological measurements under frequency sweep mode (20 °C). A range of frequency, ? from 0.1 to 100 rad/s, was employed as this is a typical range for rubber plateau. Within this range, almost frequency independent of storage moduli (G'; ~ 104 Pa as a function of hydrogel compositions were obtained. Indeed, the perfect soft-rubbery behaviour of PNIPAAm hydrogels could be confirmed and thus enabled the estimation of mesh size. Interestingly, the mesh size rubbery hydrogels determined from rheological data was in a good agreement to that from swelling experiments (~ 4 to 9 nm).