(6s) Design of Thermodynamically Consistent Coarse-Grained Models in Soft Matter

Authors: 
Chremos, A., Imperial College London

The world's population growth is enhancing the need for efficient materials, however, the design, synthesis and processing of novel materials with optimal properties for applications is an important challenge, due to the manipulation of matter at ever decreasing length scales. Computer simulation methods are essential for improving the design of novel materials, because they can provide quick and cost-effective promising directions for materials synthesis, by indicating improvements in process design or identifying reasons for shortcomings. To date, my research has been in the broad area of soft matter and with particular emphasis on methods to control or enhance self-organization on those systems. Through my work I had tackled a series of challenging problems including, but not limited to developing models to successfully reproduce morphologies with long-range order of thin films of diblock copolymers under shear [1-4] (which show promising use in synthesizing nanowires, surface modification, and pattern transfer) and provide a fundamental understanding of the structural as well as the dynamical properties of solvent-free grafted nanoparticles [5-7] (which show promising use in carbon dioxide (CO2) capture, energy capture and storage, as well as water purification). Most of these problems are multi-scaled ranging from the atomic scale to the macroscale. My current work, focus on the thermodynamics of the vapor-liquid equilibria of pure and mixed solvents of multi-functional amines, which is of great relevance for CO2 capture processes. By coupling together a predictive equation of state (EoS) for the thermodynamics and phase behavior together with robust coarse-grained models for use in explicit molecular simulation greatly enhance predictive solvent design for CO2 capture processes. The advantage of such approach is that a molecular-based equation of state can be used to obtain effective coarse-grained models that reproduce the macroscopic experimental thermophysical properties over a wide range of conditions, while conventional molecular simulation with these coarse-grained models can be performed to obtain properties (such as structure or dynamics) that are not directly accessible with the EoS. The realization of these exciting models and methodologies require a new level of understanding of the structure and properties of complex systems, as well as the capability to engineer and optimize their performance. More importantly they are not restricted to one field of research thus making them very versible. For specific molecular structures (e.g., block copolymers) there are well established methods and understanding of their behavior. We still lack a fundamental understanding of self-assembly as the building blocks deviate from the ideal molecular structures that theories are built on. Nevertheless, a more complex molecular structure would offer new possible venues for creating building blocks with selective functionality. One such example is hollow particles, e.g., nano-scale vesicles, protein cages. Such systems can be excellent candidates as nano-capsules for enzyme encapsulation and controlled release of drugs, which would have immediate relevance to many applications in physical and biological sciences. My interdisciplinary research program will therefore be dedicated to the science and engineering soft matter systems with optimal properties.

Selected Publications
[1] A. Chremos, K. Margaritis, A. Z. Panagiotopoulos, Soft Matter 6, 3588-3595 (2010).
[2] A. Chremos, P. M. Chaikin, R. A. Register, and A. Z. Panagiotopoulos, Macromolecules 45, 4406-4415 (2012).
[3] A. Chremos, P. M. Chaikin, R. A. Register, and A. Z. Panagiotopoulos, Soft Matter 8, 3803-3811, (2012).
[4] A. Chremos, A. Nikoubashman, and A. Z. Panagiotopoulos, J. Chem. Phys., 140, 054909, (2014).
[5] A. Chremos and A. Z. Panagiotopoulos, Phys. Rev. Lett. 107, 105503 (2011).
[6] A. Chremos, H. Y. Yu, D. L. Koch, and A. Z. Panagiotopoulos, J. Chem. Phys. 135, 114901 (2011).
[7] A. Chremos, D. L. Koch, and A. Z. Panagiotopoulos, J. Chem. Phys. 136, 044902 (2012).