2024 AIChE Annual Meeting
Computational Modeling of Organic Vapor Phase Infiltration
Vapor Phase Infiltration (VPI) is a sequential, repeated process where precursors embed themselves into a substrate, altering material properties such as UV resistance or conductivity. VPI has previously been used to make organic-inorganic hybrid materials. However, VPI with organic precursors and an organic substrate is not well studied and could potentially result in significant material enhancements. Here, the thermodynamics of potentially significant VPI reactions between common Molecular Layer Deposition organic precursors and a common Atomic Layer Deposition organic substrate are discussed. Three reactions were examined: polyvinyl alcohol (PVA) with isophthaloyl chloride (IC), PVA with 1,4-Diisocyanatobenzene (CB), and PVA with terephthalaldehyde (TA). Each of these reactions was first tested experimentally and then analyzed using computational methods. While the reaction of IC and PVA was observed experimentally, the other two reactions did not occur to a significant extent, despite the considerable reactivity of CB. Through the use of ARC, an open-source software, the thermodynamics of these reactions was determined (with PVA approximated by smaller oligomers). The computational results confirmed that the reaction between IC and PVA is much more favorable, than the other two reactions. However, the reaction between CB and PVA is still somewhat favorable. While the reaction between alcohols (PVA) and isocyanates (CB) is generally quite favorable, the rigidity of the PVA and the lack of solvent in this gas phase reaction could explain why there is a significant kinetic barrier in this particular reaction. Both the experimental and computational results indicate the viability of the IC PVA reaction, and the lack of viability for the TA PVA and CB PVA reactions. Further research can build on this proof of concept to develop organic VPI.
