Abstract To meet the requirements of applications, the viscoelasticity of hydrogels is usually improved by some ways, such as incorporating nanoparticles, designing network nanostructure and regulating cross-linking density. However, it is rare to improve the viscoelasticity by designing pore microstructure for hydrogels. In this work, cellulose nanocrystal (CNC)/collagen hydrogels with different pore structures (ordered tubular pores and disordered interconnected pores) and CNC concentrations (2.5–15 wt%) were prepared. The hydrogen bonding interaction between CNCs and collagen was confirmed by FTIR. The effects of pore structure and CNC concentration on the shear viscoelasticity of hydrogels were investigated, including creep, stress relaxation, frequency and strain response. The anisotropic structure and CNCs affected the creep and stress relaxation of the hydrogels, and enhanced the stiffness and dissipated energy, which demonstrated their reinforcing effect. The anisotropic structure with horizontally tubular array not only constrained collagen network rearrangement, but enhanced the elastic properties and torsion resistance of the hydrogels under torsional oscillation compared to the disordered porous structure. The mechanism for the multi-complexation between CNCs, collagen network and pore structure was proposed to understand the relationship between component, structure and hydrogel properties.

中文翻译：

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各向异性结构增强的纤维素纳米晶/胶原水凝胶：剪切粘弹性和相关增强机制

摘要 为满足应用要求，水凝胶的粘弹性通常通过掺入纳米颗粒、设计网络纳米结构和调节交联密度等方法来提高。然而，通过设计水凝胶的孔隙微结构来提高粘弹性的情况很少见。在这项工作中，制备了具有不同孔结构（有序管状孔和无序互连孔）和 CNC 浓度（2.5-15 wt%）的纤维素纳米晶（CNC）/胶原蛋白水凝胶。CNCs 和胶原蛋白之间的氢键相互作用通过 FTIR 得到证实。研究了孔结构和 CNC 浓度对水凝胶剪切粘弹性的影响，包括蠕变、应力松弛、频率和应变响应。各向异性结构和 CNCs 影响了水凝胶的蠕变和应力松弛，并增强了刚度和耗散能，这证明了它们的增强作用。与无序多孔结构相比，具有水平管状阵列的各向异性结构不仅限制了胶原网络重排，而且在扭转振荡下增强了水凝胶的弹性和抗扭性。提出了CNCs、胶原网络和孔结构之间多重络合的机制，以了解组分、结构和水凝胶性质之间的关系。与无序多孔结构相比，具有水平管状阵列的各向异性结构不仅限制了胶原网络重排，而且在扭转振荡下增强了水凝胶的弹性和抗扭性。提出了CNCs、胶原网络和孔结构之间多重络合的机制，以了解组分、结构和水凝胶性质之间的关系。与无序多孔结构相比，具有水平管状阵列的各向异性结构不仅限制了胶原网络重排，而且在扭转振荡下增强了水凝胶的弹性和抗扭性。提出了CNCs、胶原网络和孔结构之间多重络合的机制，以了解组分、结构和水凝胶性质之间的关系。