Scripting approach in hybrid organic-inorganic condensation simulation: the GPTMS proof-of-concept

摘要

Silica-based hybrid organic-inorganic (O/I) materials prepared by sol-gel chemistry exhibit unique chemical and physical properties. (3-glycidoxypropyl)trimethoxysilane (GPTMS)-based networks represent an archetype of this class of substances, with a vast range of applications. In the present study, a new computational recipe has been developed within Materials Studio software platform to generate atomistic models of GPTMS crosslinked networks. The methodology is based on molecular mechanics/dynamics schemes and assumes close proximity as a criterion for crosslinking reaction to occur. The COMPASS force-field was selected for molecular model constructions, and two charge schemes - one obtained directly from the force field and one derived from quantum-chemical calculations - were employed and compared for the prediction of the final system thermophysical properties. Starting from fully-hydrolysed GPTMS molecules, a realistic 3D network was successfully constructed, including the presence of 4- and 6-membered cyclic structures. Mechanical moduli and specific heat values estimated from equilibrated structures were selected as benchmarks for model/procedure validation. Overall, the simulation results are reasonable and in the range of experimental data available in the literature on similar systems. Thus, the proposed computational strategy has a good potential in the design and optimisation of O/I hybrid materials.