Local Mechanism Governs Global Reinforcement of Nanofiller-Hydrogel Composites
Local Mechanism Governs Global Reinforcement of Nanofiller-Hydrogel Composites
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DOI：
10.1021/acsnano.3c00716
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发表时间：
2023-10-31
期刊：
影响因子：
17.1
通讯作者：
Bischofberger，Irmgard
中科院分区：
文献类型：
--
作者：
Dellatolas，Ippolyti;Bantawa，Minaspi;Bischofberger，Irmgard
我们揭示了有吸引力的纳米填料-水凝胶复合材料的强增强机制。测量含有填料纳米粒子的水凝胶的线性粘弹性，我们表明，当填料-水凝胶相互作用是有吸引力的，可以实现在出乎意料的低体积分数的纳米填料的模量的显着增加。使用三维数值模拟，我们确定了一个通用的微观机制的增强，常见的不同组成和浓度的水凝胶基质，并含有不同大小的纳米填料。有吸引力的相互作用诱导纳米填料周围的凝胶密度的局部增加。有效的填料，由纳米填料和它们周围的致密化区域组成，组装成一个膨胀的网络，这限制了凝胶位移，并增强了整个系统的应力耦合。当应力变得强耦合时，诱导复合材料的全局增强。这种增强的物理机制，它只依赖于有吸引力的填料-基质相互作用，提供了通用的复合材料，结合联合收割机低纳米填料分数与增强的机械强度的设计策略。
We reveal the mechanism for the strong reinforcement of attractive nanofiller-hydrogel composites. Measuring the linear viscoelastic properties of hydrogels containing filler nanoparticles, we show that a significant increase of the modulus can be achieved at unexpectedly low volume fractions of nanofillers when the filler-hydrogel interactions are attractive. Using three-dimensional numerical simulations, we identify a general microscopic mechanism for the reinforcement, common to hydrogel matrices of different compositions and concentrations and containing nanofillers of varying sizes. The attractive interactions induce a local increase in the gel density around the nanofillers. The effective fillers, composed of the nanofillers and the densified regions around them, assemble into a percolated network, which constrains the gel displacement and enhances the stress coupling throughout the system. A global reinforcement of the composite is induced as the stresses become strongly coupled. This physical mechanism of reinforcement, which relies only on attractive filler–matrix interactions, provides design strategies for versatile composites that combine low nanofiller fractions with an enhanced mechanical strength.