RESEARCH

Kinetics and Chemical Mechanisms of ALI

ALI process kinetics are a complex convolution of the precursor vapor’s sorption into the polymer, solution diffusion throughout the polymer, and potential reaction with heteroatom functional groups on the polymer.  We have created a reaction-diffusion model that attempts to capture many of these processes, including the non-Fickian diffusional hindering that frequently occurs as the polymer is converted to a hybrid material.  A Google Colab simulator (based on Python code) that can be run by anyone through just a web browser can be accessed here.

Reaction–Diffusion Transport Model to Predict Precursor Uptake and Spatial Distribution in Vapor-Phase Infiltration Processes – Link

The Chemical Structure of ALI Hybrid Materials

The chemical structure of ALI hybrids is complex and often involves mixing of organic and inorganic constituents at the molecular level especially for single cycle ALI processes.  Our lab has begun classifying the structure by first whether or not the inorganic species forms a primary chemical bond to the polymer, effectively creating cross-links.

Properties and Applications of ALI Hybrid Materials

When a polymer is transformed into a hybrid material via ALI, it gains new properties unique from its parent polymer.  We have reported on a number of interesting chemical, thermophysical, electronic, and optical properties of these materials including increases in chemical stability, shifting of the glass transition temperature, altering the crystallization behavior, electronic doping of conductive polymers, and increases to the refractive index.