Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile.
Departamento de Química Analítica e Inorgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Chile.
Int J Biol Macromol. 2022 Apr 15;204:635-643. doi: 10.1016/j.ijbiomac.2022.02.059. Epub 2022 Feb 14.
One-dimensional nanoparticles such as fibers, wires, represent an exciting type of filler for obtaining nanocomposite hydrogels due to their high aspect ratio. Unlike continuous fibers, in composites with short fibers, stress transfer occurs not only at the cylindrical surface of the fiber but also at the fiber ends. This work aimed to study the influence of the length of low aspect ratio one-dimensional nanoparticles on the rheological, swelling and thermal properties of nanocomposite hydrogels. We synthesized nanocomposite hydrogels via photopolymerization of methacrylated alginate macromonomers and aluminum oxide nanoparticles, nanowires and nanofibers as fillers. The main difference between the nanoparticles lies in their length. Longer nanoparticles (nanofibers) provided a glassier structure and a more significant reinforcement to the hydrogel, for example, at the concentration of 0.5 wt% the complex modulus increased approximately 2-fold and 8-fold for nanowires and nanofibers, respectively. Similarly, the incorporation of nanofibers produced hydrogels with a lower swelling capacity (2.5-fold decrease), which was attributed to a more connected network structure due to the higher aspect ratio of the nanofibers. Finally, both nanoparticle types produced an increase in the activation energy of thermal degradation.
一维纳米粒子，如纤维、线，代表了一种令人兴奋的填充剂类型，可用于获得纳米复合水凝胶，这是由于它们的高纵横比。与连续纤维不同，在短纤维复合材料中，应力传递不仅发生在纤维的圆柱面上，也发生在纤维末端。这项工作旨在研究低纵横比一维纳米粒子的长度对纳米复合水凝胶的流变、溶胀和热性能的影响。我们通过光聚合甲基丙烯酰化海藻酸钠大分子单体和氧化铝纳米线、纳米纤维作为填充剂来合成纳米复合水凝胶。纳米粒子的主要区别在于它们的长度。较长的纳米粒子（纳米纤维）为水凝胶提供了更脆的结构和更显著的增强效果，例如，在浓度为 0.5wt%时，纳米线和纳米纤维的复模量分别增加了约 2 倍和 8 倍。同样，纳米纤维的加入使水凝胶的溶胀能力降低（降低了 2.5 倍），这归因于纳米纤维的高纵横比导致更连通的网络结构。最后，这两种类型的纳米粒子都增加了热降解的活化能。
