The present work offers a comprehensive description of the acid-induced gelation of carboxymethylcellulose (CMC), a water-soluble derivative of cellulose broadly used in numerous applications ranging from food packaging to biomedical engineering. Linear viscoelastic properties measured at various pH and CMC contents allow us to build a sol–gel phase diagram and show that CMC gels exhibit broad power-law viscoelastic spectra that can be rescaled onto a master curve following a time–composition superposition principle. These results demonstrate the microstructural self-similarity of CMC gels and inspire a mean-field model based on hydrophobic interchain association that accounts for the sol–gel boundary over the entire range of CMC content under study. Neutron scattering experiments further confirm this picture and suggest that CMC gels comprise a fibrous network cross-linked by aggregates. Finally, low-field NMR measurements offer an original signature of acid-induced gelation from a solvent perspective. Altogether, these results open avenues for the precise manipulation and control of CMC-based hydrogels.

中文翻译：

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羧甲基纤维素溶液的酸诱导凝胶化

目前的工作全面描述了羧甲基纤维素（CMC）的酸诱导凝胶化，羧甲基纤维素是一种水溶性纤维素衍生物，广泛应用于从食品包装到生物医学工程的众多应用。在不同 pH 值和 CMC 含量下测量的线性粘弹性特性使我们能够构建溶胶-凝胶相图，并表明 CMC 凝胶表现出广泛的幂律粘弹性光谱，可以按照时间-组成叠加原理重新调整到主曲线上。这些结果证明了 CMC 凝胶的微观结构自相似性，并激发了基于疏水链间缔合的平均场模型，该模型解释了所研究的整个 CMC 含量范围内的溶胶-凝胶边界。中子散射实验进一步证实了这一点，并表明 CMC 凝胶包含由聚集体交联的纤维网络。最后，低场核磁共振测量从溶剂的角度提供了酸诱导凝胶的原始特征。总而言之，这些结果为精确操纵和控制基于 CMC 的水凝胶开辟了道路。