Methylcellulose (MC) is a chemically modified polysaccharide that is partially substituted by methoxy groups. When the average substitution per monomer is intermediate, MC is water soluble, and these materials see use in a wide variety of commercial products. MC undergoes gelation and phase separation (LCST) upon heating, though the gelation mechanism of MC is poorly understood. Determination of the physical structure of MC solutions will elucidate the intermolecular interactions of MC. The sol-gel transition has been probed using rheology, and MC solutions display Winter-Chambon critical gelation. Transmission electron microscopy at cryogenic conditions (cryo-TEM) has allowed for direct observation of MC solutions at elevated temperature. Cryo-TEM investigations have shown that MC aggregates into fibril structures upon heating, which are comprised of numerous polymer chains. Small-angle x-ray and neutron scattering have been utilized to probe the physical structure of MC chains and the fit to theoretical models show good correlation to cryo-TEM results.

Physical structure of methylcellulose hydrogels near the sol-gel transition

244th National Meeting (2012)

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