Compositional Tuning Reveals a Pathway to Achieve a Strong and Lubricious Double Network in Agarose-Polyacrylamide Hydrogels
Compositional Tuning Reveals a Pathway to Achieve a Strong and Lubricious Double Network in Agarose-Polyacrylamide Hydrogels
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DOI：
10.1007/s11249-022-01604-4
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发表时间：
2022-05
影响因子：
3.2
通讯作者：
Tooba Shoaib;P. Prendergast;R. Espinosa‐Marzal
中科院分区：
文献类型：
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作者：
Tooba Shoaib;P. Prendergast;R. Espinosa‐Marzal
水凝胶具有生物组织的微观结构特征，是翻译替代材料的主要候选者。其中，双网络（DN）水凝胶以其比传统单网络水凝胶优越的上级力学性能而处于前沿。然而，控制机械和摩擦学性能的微结构的功能设计仍然是一个挑战。在这里，由物理交联的琼脂糖和化学交联的聚丙烯酰胺组成的水凝胶进行了研究，光谱，动态光散射，原子力显微镜和流变学。用最低的丙烯酰胺浓度形成可行的水凝胶，但是松散的PAAm网络没有增强琼脂糖网络。增加单体和交联剂浓度导致第二网络的快速凝胶化，产生琼脂糖网络内的不良互连的富含丙烯酰胺的结构域，以及弱且异质的水凝胶。将交联度降低到一半减缓了凝胶化，这有利于形成互穿PAAm网络，从而使强度增加两倍。虽然所研究的水凝胶的粘附性被琼脂糖显著地支配和降低，但它们的摩擦特性对组合物高度敏感。重要的是，可以通过改变吸入的流体来调节摩擦。
Hydrogels, bearing microstructural semblance to biological tissues, are prime candidates for translation replacement materials. Among them, double network (DN) hydrogels are at the forefront with their superior mechanical properties compared to conventional single network hydrogels. However, the functional design of the microstructure to control mechanical and tribological performance still poses a challenge. Here, hydrogels composed of physically crosslinked agarose and chemically crosslinked poly(acrylamide) were studied by spectroscopy, dynamic light scattering, atomic force microscopy and rheology. A viable hydrogel formed with the lowest acrylamide concentration, but the loose PAAm network did not reinforce the agarose network. Increasing the monomer and crosslinker concentration led to fast gelation of the second network, yielding poorly interconnected acrylamide-rich domains within the agarose network, and a weak and heterogenous hydrogel. Reducing the crosslinking degree to the half slowed down gelation, which favored the formation of an interpenetrating PAAm network, affording a two-fold increase in strength. While the adhesion of the investigated hydrogels is remarkably dictated and reduced by agarose, their frictional characteristics are highly sensitive to the composition. Importantly, friction can be modulated by varying the imbibed fluid.