| Abstract Scope |
Aerosol jet printing of soft polymer microstructures requires rapid control of droplet spreading, solvent evaporation, and solidification on heated substrates. Here, we investigate model droplets of an aerosol-jet-printable PDMS-mesitylene ink deposited on silicon from room temperature to 250 °C using high-speed imaging. Three liquid systems are compared: mesitylene alone, PDMS Part A diluted in mesitylene without a curing agent, and full Sylgard 184 PDMS ink containing a curing agent. Increasing substrate temperature accelerates mesitylene evaporation, enriches the droplet in PDMS, and raises viscosity, causing progressive contact-line arrest. In the full ink, Thermal crosslinking provides an additional arrest mechanism, producing reduced spreading, higher apparent contact angle, and taller final deposits at elevated temperature. By resolving transient contact diameter, height, and apparent contact angle, this study identifies the coupled evaporation–viscosity–curing pathway that governs PDMS droplet morphology and supports thermally programmed aerosol jet printing of soft polymer microarchitectures. |