Cryogels that are constructed with cellulose nanofibrils (CNF) are important as green materials for a wide range of applications. However, their utilization is limited by inherent hydrophilicity and insufficient mechanical properties. Herein, a processable CNF/nanochitin (NCh)-stabilized Pickering emulsion that contains polylactide (PLA) in the oil phase is developed to directly produce ternary composite cryogels via freeze-drying. The complexation of CNF with NCh promotes CNF adsorption at the surface of PLA droplets, resulting in formation of uniform Pickering PLA droplets. The CNF/NCh complex-stabilized PLA droplets are easy to be translated to the internal structure of the cryogels, exhibiting lightweight nature and possessing highly porous structure. The interconnected network and lamellar structure formed by the CNF/NCh complexes, associating with inclusion of PLA particles, improve the cryogel structure integrity upon post-processing and endow hydrophilic cryogel with water resistance. This study offers a straightforward and eco-friendly Pickering emulsion template on fabrication of the CNF-based composite cryogel with controllable microstructure and mechanical performance, broadening construction of nanocellulose-based composites.

中文翻译：

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用于含有纤维素纳米纤丝和纳米甲壳素的复合冷冻凝胶的可加工皮克林乳液

用纤维素纳米原纤维 (CNF) 构建的冷冻凝胶作为绿色材料具有广泛的应用价值。然而，它们的利用受到固有的亲水性和机械性能不足的限制。在此，开发了一种在油相中含有聚丙交酯（PLA）的可加工的CNF/纳米壳丁（NCh）稳定的Pickering乳液，通过冷冻干燥直接生产三元复合冷冻凝胶。 CNF 与 NCh 的络合促进 CNF 在 PLA 液滴表面的吸附，从而形成均匀的 Pickering PLA 液滴。 CNF/NCh复合物稳定的PLA液滴很容易转化为冷冻凝胶的内部结构，表现出轻质性质并具有高度多孔的结构。 CNF/NCh复合物形成的互连网络和层状结构，与PLA颗粒的包合物相结合，改善了后处理后的冷冻凝胶结构完整性，并赋予亲水性冷冻凝胶耐水性。这项研究为制造具有可控微观结构和机械性能的 CNF 基复合冷冻凝胶提供了一种简单且环保的 Pickering 乳液模板，拓宽了纳米纤维素基复合材料的结构。