Spatial atomic layer deposition for high-performance moisture barrier coatings

Overview

This solution offers a roll-to-roll spatial atomic layer deposition (SALD) capability for producing ultra-thin metal oxide moisture barrier coatings on flexible substrates such as plastics, metals, and papers. The technology enables fast, solvent-free deposition at metres-per-second speeds, making it suitable for scalable manufacturing of barrier primers and top coatings. By engineering multilayered oxide stacks, the approach aims to deliver superior moisture barrier performance compared to thicker, single-component coatings, while minimizing material usage and maintaining flexibility during processing and end-use.

The coatings are designed for applications requiring robust moisture protection, including flexible packaging, organic electronics, and other roll-to-roll manufactured products. Because the oxide layers form primary chemical bonds with the substrate, they provide strong adhesion and stability across a range of processing temperatures.

Technical specifications

• Deposition method: Spatial atomic layer deposition (SALD), enabling solvent-free, roll-to-roll coating at metres per second
• Coating materials: Non-toxic metal oxides including aluminum oxide, zinc oxide, titanium oxide, tin oxide, tungsten oxide, and copper oxide
• Thickness precision: Approximately 0.1 nanometers
• Typical coating thickness: A few tens of nanometers, preserving flexibility
• Substrate compatibility: Metals, plastics, and papers
• Coating architecture: Single-component and multilayer stacks (e.g., ZnOx-TiOx-ZnOx) designed to suppress grain boundary formation and enhance barrier performance
• Demonstrated performance: Single-component spatial ALD aluminum oxide coatings have achieved water vapor transmission rates below 3×10⁻³ grams per square metre per day under laboratory conditions
• Processing tolerance: Stable across a range of processing temperatures, with chemical bonding for strong adhesion

Technology readiness level

The technology has been validated at laboratory scale, with demonstrated water vapor transmission rates for single-component aluminum oxide coatings on flexible substrates. The research group has designed and built the first two spatial ALD systems in Canada, including a commercial-scale system (patent pending), and is actively developing novel spatial ALD reactors for commercial roll-to-roll coating.

Future validation work will deposit different single-component and multilayer non-toxic metal oxide coatings as both primer and top coatings, measure water vapor transmission rates before and after exposure to simulated processing conditions (such as vertical form-fill-seal forming conditions), and characterize the coatings to explain performance variation and optimize multilayer barrier designs. Biodegradability evaluation will also be performed in accordance with applicable standards.