Camerin Fabrizio, Fernández-Rodríguez Miguel Ángel, Rovigatti Lorenzo, Antonopoulou Maria-Nefeli, Gnan Nicoletta, Ninarello Andrea, Isa Lucio, Zaccarelli Emanuela
CNR Institute for Complex Systems, Uos Sapienza , Piazzale Aldo Moro 2 , 00185 Roma , Italy.
Department of Basic and Applied Sciences for Engineering , Sapienza University of Rome , Via Antonio Scarpa 14 , 00161 Roma , Italy.
ACS Nano. 2019 Apr 23;13(4):4548-4559. doi: 10.1021/acsnano.9b00390. Epub 2019 Mar 19.
Soft particles display highly versatile properties with respect to hard colloids and even more so at fluid-fluid interfaces. In particular, microgels, consisting of a cross-linked polymer network, are able to deform and flatten upon adsorption at the interface due to the balance between surface tension and internal elasticity. Despite the existence of experimental results, a detailed theoretical understanding of this phenomenon is still lacking due to the absence of appropriate microscopic models. In this work, we propose an advanced modeling of microgels at a flat water/oil interface. The model builds on a realistic description of the internal polymeric architecture and single-particle properties of the microgel and is able to reproduce its experimentally observed shape at the interface. Complementing molecular dynamics simulations with in situ cryo-electron microscopy experiments and atomic force microscopy imaging after Langmuir-Blodgett deposition, we compare the morphology of the microgels for different values of the cross-linking ratios. Our model allows for a systematic microscopic investigation of soft particles at fluid interfaces, which is essential to develop predictive power for the use of microgels in a broad range of applications, including the stabilization of smart emulsions and the versatile patterning of surfaces.
与硬胶体相比，软颗粒具有高度多样的特性，在液 - 液界面更是如此。特别是由交联聚合物网络组成的微凝胶，由于表面张力和内部弹性之间的平衡，在吸附到界面时能够变形并变平。尽管有实验结果，但由于缺乏合适的微观模型，对这一现象仍缺乏详细的理论理解。在这项工作中，我们提出了一种在平坦水/油界面上对微凝胶进行高级建模的方法。该模型基于对微凝胶内部聚合物结构和单颗粒性质的真实描述，能够重现其在界面上实验观察到的形状。通过将分子动力学模拟与原位低温电子显微镜实验以及朗缪尔 - 布洛杰特沉积后的原子力显微镜成像相结合，我们比较了不同交联比下微凝胶的形态。我们的模型允许对流体界面处的软颗粒进行系统的微观研究，这对于开发微凝胶在广泛应用中的预测能力至关重要，这些应用包括智能乳液的稳定和表面的多功能图案化。
