目的：微凝胶与刚性纳米颗粒的络合是一种有效的方法，可以为所得的杂化颗粒赋予新颖的性能和功能，以用于例如在光学中的应用，催化作用,或用于稳定泡沫/乳液。纳米颗粒影响聚合物网络的构象，无论是在大量含水环境中，还是在微凝胶吸附在流体界面时，通过调节微凝胶的大小，刚度和表观接触角。
方法：这里，我们提供详细的调查，使用光散射，原位原子力显微镜和纳米压痕实验，在水性悬浮液中混合后，聚（N-异丙基丙烯酰胺）微凝胶与疏水化二氧化硅纳米颗粒之间的相互作用，以阐明纳米颗粒掺入后的网络重组。
结果：纳米颗粒的添加降低了微凝胶的体积溶胀和热响应。当吸附在油水界面时，更高的纳米粒子的比例影响微凝胶的刚度以及它们的疏水/亲水特性通过增加它们的有效接触角，因此调节界面压缩时的单层响应。总的来说,这些结果提供了对不同环境中混合微凝胶的复杂构象的基本理解，并为设计新材料提供了灵感，其中软聚合物网络和纳米颗粒的组合可能导致额外的功能。
OBJECTIVE: The complexation of microgels with rigid nanoparticles is an effective way to impart novel properties and functions to the resulting hybrid particles for applications such as in optics, catalysis, or for the stabilization of foams/emulsions. The nanoparticles affect the conformation of the polymer network, both in bulk aqueous environments and when the microgels are adsorbed at a fluid interface, in a non-trivial manner by modulating the microgel size, stiffness and apparent contact angle.
METHODS: Here, we provide a detailed investigation, using light scattering, in-situ atomic force microscopy and nano-indentation experiments, of the interaction between poly(N-isopropylacrylamide) microgels and hydrophobized silica nanoparticles after mixing in aqueous suspension to shed light on the network reorganization upon nanoparticle incorporation.
RESULTS: The addition of nanoparticles decreases the microgels\' bulk swelling and thermal response. When adsorbed at an oil-water interface, a higher ratio of nanoparticles influences the microgel\'s stiffness as well as their hydrophobic/hydrophilic character by increasing their effective contact angle, consequently modulating the monolayer response upon interfacial compression. Overall, these results provide fundamental understanding on the complex conformation of hybrid microgels in different environments and give inspiration to design new materials where the combination of a soft polymer network and nanoparticles might result in additional functionalities.
