# A Novel Approach to Cure-on-Demand Coatings Using Ammonia to Catalyze Thiol-Acrylate and Thiol-Epoxy Reactions

## TL;DR

A new coating method uses ammonia to control chemical reactions, offering a one-pot, eco-friendly approach with adjustable curing times.

## Contribution

A novel ammonia-catalyzed, one-pot coating system using a urea-urease clock reaction for programmable curing.

## Key findings

- Ammonia from urea-urease reaction delayed curing for up to 30 days with stabilizers.
- Thiol-epoxy coatings showed better mechanical strength despite longer cure times.
- Aluminum foil effectively prevented ammonia loss during delayed curing.

## Abstract

Cure-on-demand thiol-acrylate and thiol-epoxy coatings
were developed
by using ammonia as a catalyst. This novel method is a one-pot formulation
that eliminates the need for volatile organic components and introduces
a novel curing technique for coatings. Two ammonia sources were employed:
a 30% aqueous solution of ammonia and ammonia generated by the urea-urease
clock reaction with watermelon seed powder (WMSP) serving as a source
of the urease enzyme. The pot lives were extended to at least 30 days
by adding stabilizers. The use of the urea-urease clock reaction produced
ammonia after a programmable delay, which allowed the coating to be
covered with aluminum foil to prevent ammonia loss. The cure times
for thiol-acrylate coatings were shorter, although their mechanical
strengths were lower compared to thiol-epoxy coatings, which had longer
cure times but superior mechanical properties.