Development of robust printed circuit textile based on layer-by-layer assembly with PEDOT:PSS and ionic polymer compounds

Abstract

In contrast with rigid silicon-based devices, electronic textile (e-textile) that provides desired electronic functionalities into garments shows unique superior characteristics, such as light weight, high flexibility, high stretchability, conformality, and daily usability. Regarding the integration level, e-textile technology shows excellent application capabilities, including human health monitoring, environmental sensing, information displaying, human-machine interfacing, and energy harvesting/storage, but has still some challenging issues; 1) conformal patterning technology on the textile, 2) development of highly conductive and robust electrodes using printable conductive dye, and 3) electrical and mechanical connection with patterns. This thesis highlights strategic methods to address three issues. Chapter 1 in this thesis overviews the recent study of e-textile and printable conductive material for conductive textile developed so far. In particular, this chapter overviews poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composites and the concept of printed circuit textile (PCT). Furthermore, the layer-by-layer (LBL) coating process will be discussed regarding the patterning method. Chapter 2 describes the methodology of printing conductive dye on the textile with conformal lamination and high patterning resolution. The challenging issue is fabricating PCT with low resistance and mechanical stability under various deformations, which causes some electrical failures. Simultaneously, the electrode pattern should be controllable to form desired circuit design. In this Chapter 2, a developed stencil-type LBL coating process based on PEDOT:PSS:Ag nanowire and chitosan is discussed to demonstrate controlling electrode pattern resolution and electrically and mechanically reliable PCT. Chapter 3 depicts a strategy of selecting counter martial against PEDOT:PSS during the LBL coating process. The candidates of the counter material, including monomeric or polymeric ionic polymers, are systematically discussed about the electrical and mechanical properties. Also, interfacial adhesion related to the robustness of the multilayer-coated LBL process with PEDOT:PSS was analyzed. In this Chapter 3, a quiltable e-textile application is developed through a water-assisted welding process using ionic bonding between PEDOT:PSS and counter materials.