E-textile additive process management

"Pireta Ltd is an e-textile start-up business that has been spun out of the National Physical Laboratory (NPL). Pireta's technology uses an innovative chemical process to add electrical conductivity to areas of fabric. Conductive patterns can be prepared onto textiles with high resolution. Our technology is similar to, and competes with, conventional inks but differs in important respects. Pireta technology allows electronic systems to be assembled directly on fabrics, enabling a new generation of truly wearable smart garments and e-textiles.

The fabric is first printed with a silver nanoparticle (AgNP) catalyst pattern. The fabric is then passed into an electroless copper (e-Cu) plating bath, in which the process attaches a thin, highly-durable copper layer at the fibre level, resulting in excellent conductivity but with no impact on the performance of the textile. This means that electronics can be integrated into stretchable, breathable, washable smart garments that can be worn close to the body with ease and comfort, making them truly wearable.

The vision of this project is to create high quality ink system at volume. Today we have a laboratory scale process and need to create new process interventions to achieve our aim. In detail we need to achieve high retention of silver nanoparticles on the fabric substrate from a printing process. Leeching of nanoparticles (NP), creates waste, poisons our e-Cu, reduces conductivity in a final product. Innovation by NML working on developing metrology methods that will provide critical feedback to Pireta, to allow it innovate and create deposition techniques for AgNP. Furthermore, in our e-Cu process with very high deposition rates, because we plate on fabrics, the dynamic between consumption and replenishment will be studied. NML's compositional measurement of the e-Cu will be invaluable in creating the replenishment strategy.

NML will develop a single particle analysis technique, and Pireta will innovate new AgNP deposition techniques. The reduction in silver nanoparticle leach out will include washing procedures of printed fabric samples and analysis of the silver nanoparticle concentration. Hence, new procedures for the deposition will lead to reduced amounts of silver nanoparticle leach-out from printed fabric, significantly improving e-Cu bath quality. The project will validate techniques for a range of fabrics."