Download or read book Multiscale Modeling of Self-assembly and Phase Behavior of Complex Fluids written by Kyeong-jun Jeong and published by . This book was released on 2020 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembly and phase separation in mixtures are processes of great interest which provide large opportunities for designing novel nanomaterials. Since the aggregation behaviors are governed by noncovalent interactions and configurational entropy of molecules, computational modeling can shed light on the design principles by detecting molecular details beyond the resolution of experiments. We use molecular dynamics (MD) simulations to model bulk condensed matter systems, then inspect the topology and time evolution of the systems from atomic scales to nanometer scales for time of nanoseconds. We characterize the thermodynamic driving force of the association of ionic 'gemini' surfactants in water. We find that different headgroup electrostatics and size lead to qualitatively different intermolecular configurations of the surfactant associates, then discriminate whether the process is energetically or entropically driven. We also model low-symmetry packing phases comprised of spherical micelles of simple ionic surfactants. Here we notice the frustration of ideal packing by electrostatic interactions brings total inhomogeneity of structure and dynamics. These studies provide insight that the detailed topology and conditions of amphiphile self-assembly are hierarchically affected by chemical details of individual molecules and overall partitions of the system constituents. In another path, we utilize first-principles to develop force fields which can explicitly represent electronic polarizations as a response to environments. We demonstrate the polarization feature grants large benefits on the model transferability on hydrogen-bonding systems, regarding our applications on the urea/water mixture, and the choline chloride/urea mixture. Our new polarizable force field of urea is working well on both crystal and aqueous solution phases, and it is superior than nonpolarizable force field especially in the prediction of temperature-dependent solubility in water. Also, our choline chloride force field is combined with urea, and shows fair accuracy of predicting hydrogen bond network microstructure and self-diffusion of the bulk liquid. Thus, we conclude our studies enable comprehensive modeling of nanoscale processes while implementing chemical details with reasonable computational costs.