期刊
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
卷 24, 期 3, 页码 -出版社
MDPI
DOI: 10.3390/ijms24032003
关键词
water; hydrophobic effect; local order; relaxation times; self-diffusion
Interactions between nanoparticles have a significant impact on their organization and dynamics. The competition between hydrophobic and hydrophilic forces in nanoparticle solutions has been observed to undergo a transition from hydrophilic to hydrophobic behavior with increasing temperature. This transition is dependent on temperature and nanoparticle volume fraction, and the hydrophobic effect plays a crucial role in determining the interaction properties of the studied nanostructures' surface.
Interactions between nanoparticles (NPs) determine their self-organization and dynamic processes. In these systems, a quantitative description of the interparticle forces is complicated by the presence of the hydrophobic effect (HE), treatable only qualitatively, and due to the competition between the hydrophobic and hydrophilic forces. Recently, instead, a sort of crossover of HE from hydrophilic to hydrophobic has been experimentally observed on a local scale, by increasing the temperature, in pure confined water and studying the occurrence of this crossover in different water-methanol solutions. Starting from these results, we then considered the idea of studying this process in different nanoparticle solutions. By using photon correlation spectroscopy (PCS) experiments on dendrimer with OH terminal groups (dissolved in water and methanol, respectively), we show the existence of this hydrophobic-hydrophilic crossover with a well defined temperature and nanoparticle volume fraction dependence. In this frame, we have used the mode coupling theory extended model to evaluate the measured time-dependent density correlation functions (ISFs). In this context we will, therefore, show how the measured spectra are strongly dependent on the specificity of the interactions between the particles in solution. The observed transition demonstrates that just the HE, depending sensitively on the system thermodynamics, determines the hydrophobic and hydrophilic interaction properties of the studied nanostructures surface.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据