Objective

The goal of this project is to develop water-based and non-fluorinated Janus particle additives that can be directly added to coating formulations to produce omniphobic fabric coatings. Fabrics treated with such coatings can repel both hydrophilic and hydrophobic chemicals, without using per- and polyfluoroalkyl substances compounds. The composition, geometry and formulation of Janus particles will be investigated for both omniphobic performance and accomplishment of the required coating properties. The effort will focus on the repellency of coatings on nylon and cotton fibers. There are three objectives to show the proof-of-concept:

  1. Synthesize Janus particles that can stratify with the commercial textile coatings 
  2. Maximize the repellency through control of surface microstructures 
  3. Benchmark the performance of coatings added with Janus particles

Technical Approach

This project will use a novel Janus nanoparticle additive approach for achieving the omniphobic coatings. Instead of completely reinventing a new coating system, the idea is to work with the current commercially available binders and create omniphobic coatings by directly adding Janus particles as additives into the coating formulation. Janus particle additives are water dispersible and made from non-fluorinated Environment, Safety, and Occupational Health (ESOH) low-risk materials. This idea is based on the recent discovery that Janus particles can accumulate at the top of the coating surface through a unique self-stratification process. The hydrophobic side of the Janus particles will orient toward the air to create an omniphobic layer, while the hydrophilic side of the Janus particles embedded in the coating matrix to provide anchor and adhesion. By engineering both sides of the Janus particles through surface chemistry, crosslinking, surface roughness, and mixing particles of different sizes, the performance of the omniphobic surface can be further improved.

Benefits

There are several advantages of the new technology: 

  • Janus particle additives can be made with chemicals with no ESOH concerns. They are environmentally friendly and broadly compatible with different types of commercially available water-based textile coatings for different textile types. 
  • Through the design of surface chemistry and morphology of Janus particle additives, the impact of the coating properties can be minimized, such as adhesion and temperature cycling. 
  • The chemistry and composition of Janus particle additives can be optimized to maximize the key coating performance, including abrasion resistance, fastness, and resistance to ultra violet light. 
  • Janus particles are synthesized using scalable emulsion polymerization already adopted by the chemical industry; therefore, this method is scalable and can significantly lower the barrier to adoption by the coating industry.