Wang Kaitlin, Winey Karen I
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America.
Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America.
ACS Macro Lett. 2024 Sep 17;13(9):1192-1197. doi: 10.1021/acsmacrolett.4c00438. Epub 2024 Aug 26.
This study examines nanoparticle diffusion in crowded polymer nanocomposites by diffusing small AlO nanoparticles (NPs) in SiO-loaded P2VP matrices. Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) measures AlO NP diffusion coefficients within a homogeneous PNC background of larger, immobile SiO NPs. By developing a geometric model for the average interparticle distance in a system with two NP sizes, we quantify nanocomposite confinement relative to the AlO NP size with a bound layer. At low SiO concentrations, AlO NP diffusion aligns with the neat polymer results. In more crowded nanocomposites with higher SiO concentrations where the interparticle distance approaches the size of the mobile AlO NP, the 6.5 nm AlO NPs diffuse faster than predicted by both core-shell and vehicular diffusion models. Relative to our previous studies of NPs diffusing into polymers, these findings demonstrate that the local environment in crowded systems significantly complicates NP diffusion behavior and the bound layer lifetimes.
本研究通过在负载SiO的P2VP基质中扩散小的AlO纳米颗粒（NPs），研究了纳米颗粒在拥挤的聚合物纳米复合材料中的扩散。飞行时间二次离子质谱（ToF-SIMS）测量了在较大的、固定的SiO NPs的均匀PNC背景内的AlO NP扩散系数。通过为具有两种NP尺寸的系统中的平均粒子间距离建立几何模型，我们用一个束缚层来量化相对于AlO NP尺寸的纳米复合材料限制。在低SiO浓度下，AlO NP扩散与纯聚合物的结果一致。在SiO浓度较高、粒子间距离接近可移动的AlO NP尺寸的更拥挤的纳米复合材料中，6.5 nm的AlO NPs扩散速度比核壳扩散模型和载体扩散模型预测的都要快。相对于我们之前对NPs扩散到聚合物中的研究，这些发现表明，拥挤系统中的局部环境显著使NP扩散行为和束缚层寿命复杂化。
