The effect of the filler size on the structural and mechanical properties of an attractive fibrillated network composed of oxidised cellulose nanofibrils (OCNF) in water was investigated. Silica nanoparticles with a diameter of ca. 5 nm (SiNp₅) and and ca. 158 nm (SiNp₁₅₈) were chosen as non-interacting fillers of the OCNF network. These filler sizes were chosen, respectively, to have a particle size which was either similar to that of the network mesh size or much larger than it. Contrast matched small angle neutron scattering (SANS) experiments revealed that the presence of the fillers (SiNp₅ and SiNp₁₅₈) did not perturb the structural properties of the OCNF network at the nanometer scale. However, the filler size difference strongly affected the mechanical properties of the hydrogel upon large amplitude oscillatory shear. The presence of the smaller filler, SiNp₅, preserved the mechanical properties of the hydrogels, while the larger filler, SiNp₁₅₈, allowed a smoother breakage of the network and low network recoverability after breakage. This study showed that the filler-to-mesh size ratio, for non-interacting fillers, is pivotal for tailoring the non-linear mechanical properties of the gel, such as yielding and flow.

中文翻译：

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有吸引力的原纤化网络中的填料尺寸效应：结构和流变学的观点

研究了填料尺寸对水中由氧化纤维素纳米纤丝（OCNF）组成的有吸引力的原纤化网络的结构和机械性能的影响。二氧化硅纳米粒子的直径约为 5 nm（SiNp ₅）和。选择158 nm（SiNp ₁₅₈）作为OCNF网络的非交互填充物。分别选择这些填料的尺寸，以使其具有与网络筛孔尺寸相似的粒径或比其大得多的粒径。对比匹配小角中子散射（SANS）实验表明存在填料（SiNp ₅和SiNp ₁₅₈）在纳米尺度上没有干扰OCNF网络的结构特性。然而，在大振幅振荡剪切时，填料尺寸差异强烈影响水凝胶的机械性能。较小的填料SiNp ₅的存在保留了水凝胶的机械性能，而较大的填料SiNp ₁₅₈可使网状结构更平滑地断裂，断裂后的网络可恢复性较低。这项研究表明，对于非相互作用的填料，填料与筛孔的尺寸比对于调整凝胶的非线性机械性能（例如屈服和流动）至关重要。