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SANS Studies on Tetra-PEG Gel under Uniaxial Deformation

Macromolecules2011Vol. 44(5), pp. 1203–1210

Citations Over TimeTop 16% of 2011 papers

Takuro Matsunaga, H. Asai, Yuki Akagi, Takamasa Sakai, Ung‐il Chung, Mitsuhiro Shibayama

Abstract

Studies on the deformation mechanism of polymer networks with small-angle neutron scattering (SANS) were carried out for Tetra-PEG gels, that is, poly(ethylene glycol) (PEG) networks prepared from tetra-functional A- and B-type macromers consisting of PEG by cross-end-coupling. Tetra-PEG gels are hydrogels with narrow-dispersed polymer chains. The molecular weights of the prepolymers were 20k and 40k. SANS measurements were conducted for uniaxially stretched Tetra-PEG gels. Although the SANS patterns for deformed Tetra-PEG gel-20k showed small anisotropy, that is, prolate and oblate patterns with respect to the stretching direction at low and high-q regions, respectively, Tetra-PEG gel-40k exhibited no anisotropy at all in the low-q region, even in a gel stretched by five times. This indicates that Tetra-PEG gel-40k is a homogeneous network free from inhomogeneities, such as dangling chains and entanglements and can be regarded as an “ideal” polymer network. The deformation mechanism of Tetra-PEG gels was discussed in comparison with those for phantom Gaussian chain model and others, suggesting that the concentration fluctuations by thermal motions surpass the chain anisotropy introduced by deformation.

Citations Over TimeTop 16% of 2011 papers

Abstract

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