Houston Judith Elizabeth, Fruhner Lisa, de la Cotte Alexis, Rojo González Javier, Petrunin Alexander Valerievich, Gasser Urs, Schweins Ralf, Allgaier Jürgen, Richtering Walter, Fernandez-Nieves Alberto, Scotti Andrea
European Spallation Source ERIC, Box 176, SE-221 00 Lund, Sweden.
Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), 52425 Jülich, Germany.
Sci Adv. 2022 Jul;8(26):eabn6129. doi: 10.1126/sciadv.abn6129. Epub 2022 Jul 1.
The bulk modulus, , quantifies the elastic response of an object to an isotropic compression. For soft compressible colloids, knowing is essential to accurately predict the suspension response to crowding. Most colloids have complex architectures characterized by different softness, which additionally depends on compression. Here, we determine the different values of for the various morphological parts of individual nanogels and probe the changes of with compression. Our method uses a partially deuterated polymer, which exerts the required isotropic stress, and small-angle neutron scattering with contrast matching to determine the form factor of the particles without any scattering contribution from the polymer. We show a clear difference in softness, compressibility, and evolution of between the shell of the nanogel and the rest of the particle, depending on the amount of cross-linker used in their synthesis.
体积模量 (K) 量化了物体对各向同性压缩的弹性响应。对于柔软可压缩的胶体，了解 (K) 对于准确预测悬浮液对拥挤的响应至关重要。大多数胶体具有以不同柔软度为特征的复杂结构，而柔软度还取决于压缩情况。在此，我们确定了单个纳米凝胶各个形态部分的不同 (K) 值，并探究了 (K) 随压缩的变化。我们的方法使用一种部分氘代聚合物，它施加所需的各向同性应力，并利用对比度匹配的小角中子散射来确定颗粒的形状因子，而聚合物不会产生任何散射贡献。我们表明，根据纳米凝胶壳层与颗粒其余部分在合成中使用的交联剂数量不同，它们在柔软度、可压缩性以及 (K) 的演变方面存在明显差异。
