The Rubber Elasticity of Poly(N-isopropylacrylamide) Hydrogel Networks

Abstract:

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, ω 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).

• Periodical: Advanced Materials Research (Volume 812)
• Pages: 210-215
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.812.210
• Online since: September 2013
• Authors: Nadia Adrus, Mathias Ulbricht
• Keywords: Hydrogel, Network Structure, Photopolymerization, PNIPAAm, Rubber Elasticity

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