AI 中文总结
该研究探究了交联剂密度与微凝胶浓度对PNIPAM微凝胶稳定的水基泡沫发泡性及稳定性的影响，证实不同长度尺度间特性存在良好关联，为调控泡沫性能提供了多尺度依据。
AI 中文摘要
水基泡沫在不同长度尺度上具有多种结构基元：宏观泡沫、气泡、泡沫液膜以及空气/水界面。本研究中，通过向PNIPAM微凝胶的水分散体系中鼓入气体来制备宏观泡沫，这些微凝胶因具有表面活性而充当泡沫稳定剂。微凝胶的刚度及其界面活性可通过改变交联剂密度进行调控。研究人员探究了交联剂密度和微凝胶浓度对所得泡沫形成特性（发泡性）及泡沫稳定性的影响：较低的交联剂密度和较高的微凝胶浓度可提升发泡性，生成气泡更小、液体分数更高的泡沫，并增强泡沫稳定性。这些观测结果与微凝胶在单个空气/水界面的行为相关联，该行为通过悬滴张力法和朗缪尔压缩实验进行检测，同时微凝胶在单个自由泡沫液膜中的迁移率则通过薄膜压力天平测定。研究结果凸显了不同长度尺度间的良好一致性：发泡性提升与表面张力更快下降相关，而泡沫稳定性提高则与微凝胶覆盖的单个空气/水界面的表面弹性模量升高以及泡沫液膜中迁移率降低相关。
英文摘要
Aqueous foams possess multiple structural motifs across different length scales: macroscopic foam, bubbles, foam films and the air/water interface. In this study, macroscopic foams are generated by sparging gas through an aqueous dispersion of PNIPAM microgels which act as foam stabilisers due to their surface activity. The stiffness of the microgels and thus their interfacial activity are tuned by variation of the cross-linker density. The effect of the cross-linker density and the microgel concentration on the resulting foam formation properties (foamability) and the foam stability are investigated. A lower cross-linker density and a higher microgel concentration enhance the foamability, generate foams with smaller bubbles and higher liquid fractions, and increase the foam stability. These observations are correlated with the microgel behavior at the single air/water interface examined by pendant drop tensiometry and Langmuir compression experiments as well as the mobility in single free-standing foam films determined using a Thin Film Pressure Balance. Our findings highlight good agreement across all length scales: increased foamability correlates with a faster decrease in surface tension, and higher foam stability with a higher surface elastic modulus of a microgel-covered single air/water interface and decreasing mobility in foam films.
