Structural heterogeneities in starch hydrogels

• Published in: Carbohydrate polymers 2020-12, Vol.249, p.116834-116834, Article 116834
• Main Authors: Koev, Todor T., Muñoz-García, Juan C., Iuga, Dinu, Khimyak, Yaroslav Z., Warren, Frederick J.
• Format: Article
• Language: English
• Subjects: CP/MAS NMR; CPSP/MAS NMR; Internal dynamics; Network organisation; NMR spectroscopy; Starch hydrogels
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2020.116834

•Produced starch hydrogels through high temperature-pressure gelatinisation.•Employed a range of NMR methods to probe the molecular mobility and water dynamics.•Reported for the first time highly dynamic starch chains in the solvent phase of gels.•Correlated the degree of chain structural mobility with bulk properties.•Revealed a previously unknown level of molecular organisation in starch gels. Hydrogels have a complex, heterogeneous structure and organisation, making them promising candidates for advanced structural and cosmetics applications. Starch is an attractive material for producing hydrogels due to its low cost and biocompatibility, but the structural dynamics of polymer chains within starch hydrogels are not well understood, limiting their development and utilisation. We employed a range of NMR methodologies (CPSP/MAS, HR-MAS, HPDEC and WPT-CP) to probe the molecular mobility and water dynamics within starch hydrogels featuring a wide range of physical properties. The insights from these methods were related to bulk rheological, thermal (DSC) and crystalline (PXRD) properties. We have reported for the first time the presence of highly dynamic starch chains, behaving as solvated moieties existing in the liquid component of hydrogel systems. We have correlated the chains’ degree of structural mobility with macroscopic properties of the bulk systems, providing new insights into the structure-function relationships governing hydrogel assemblies.