(95e) Designing Molecular Building Blocks to Minimize Defects in the Formation of Surface Covalent Organic Frameworks
Covalent organic frameworks (COFs) have a great potential for constructing molecular sieves for use in separations processes. COFs can form a diverse array of long-range porous networks from various combinations of molecular building blocks, and the intelligent selection of these building blocks can in principle allow the formation of targeted COF structures. While this selection process may be based on purely geometric arguments, neglecting thermodynamic and kinetic factors gives poor guidance on what COF structures could be realistically achieved. In this research, we used molecular dynamics simulations to study how the geometry of building blocks and the effective interactions between them affects the final structure of 2-dimensional COFs. We developed a general method for creating coarse-grained models of planar molecular building blocks and give guidance on how directionality, selectivity, and reaction chemistry could be represented. Through molecular dynamics simulations, we identified what properties of building blocks prevent misbonds, control the predominant pore geometry and the distribution of pore sizes, and facilitate self-assembly.