Tuning the cross-linking of phenolic aerogel by templates and solvents: a molecular dynamics study

Understanding the microscopic mechanisms of pore formation is essential for designing high-performance phenolic resin (PF) aerogels. In this work, a reaction-radius-driven Perl algorithm was developed to construct three-dimensional crosslinked PF networks, and molecular dynamics simulations were employed to investigate the roles of PMMA templates and solvents during reaction-induced phase separation (RIPS). The results reveal that the templates jointly regulate chain mobility and molecular interactions, thereby controlling pore size, morphology, and distribution of PF. Higher PMMA content enlarges pore size by strengthening PF-PMMA interactions and weakening PF-PF network constraints. Notably, an optimal PMMA chain length (DP60) was identified, at which relatively weaker PF-PMMA interfacial interactions promote PMMA self-aggregation, leading to the maximum pore size and FFV. Solvent molecules preferentially interact with both PF and PMMA, weakening direct PF-PMMA interactions and promoting hierarchical pore formation. This study provides molecular-level insights into how templating agents regulate aerogel architecture and offers a framework for rationally designing PF aerogels with tailored porosity.