Flexible Conductive Polymer Film Grafted with Azo-Moieties and Patterned by Light Illumination with Anisotropic Conductivity

Abstract

In this work, we present the method for the creation of an anisotropic electric pattern on thin poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) films through PSS grafting by azo-containing moieties followed by light-induced polymers redistribution. Thin PEDOT:PSS films were deposited on the flexible and biodegradable polylactic acid (PLLA) substrates. The light-sensitive azo-groups were grafted to PSS using the diazonium chemistry followed by annealing in methanol. Local illumination of azo-grafted PEDOT:PSS films through the lithographic mask led to the conversion of azo-moieties in Z-configuration and further creation of the lateral gradient of azo-isomers along the film surface. The concentration gradient led to the migration of PSS away from the illuminated area, increasing the PEDOT chains’ concentration and the corresponding increase of local electrical conductivity in the illuminated place. Utilization of mask with linear pattern results in the appearance of conductive PEDOT-rich and non-conductive PSS-rich lines on the film surface, and final, lateral anisotropy of electric properties. Our work gives an optical lithography-based alternative to common methods for the creation of anisotropic electric properties, based on the spatial confinement of conductive polymer structures or their mechanical strains.

All organic homojunction PEDOT:PSS p–n diode

“…It is most probable that the OH group of isopropanol controls the role of PSS and thus reduces the hydrophobic character of PEDOT. These AFM images confirm that isopropanol plays a significant role in the phase separation process between the conductive PEDOT and the insulating PSS within the PEDOT:PSS [11][12][13] . In addition, and due to the hydrophilic properties of isopropanol, the phase-separated PSS chains are most likely to be dissolved and thus removed from the PEDOT:PSS film surface.…”

PEDOT and PEDOT:PSS thin-film electrodes: patterning, modification and application in stretchable organic optoelectronic devices

“…PEDOT lines with widths of 5 μm (electropolymerized) and 900 nm (VPP) were prepared on both rigid and flexible substrate with only 0.5 wt% initiator added. Rather than structural design of the EDOT monomer, Kalachyova et al 107 grafted azo-groups onto PSS to create patterned PEDOT:PSS on the polylactic acid on the basis of photo-induced configuration conversion of azo-groups. The micro periodic patterns were equipped with anisotropic electric properties due to the migration of the grafted PSS.…”

The Effect of Azo Moiety on the Electrical Conductivity of Oxadiazole and Triazole Containing Polymers

“…Organic polymers with an azo active group were used in lithium ion batteries, whereby the azo moiety can enhance the electrical conductivity by connecting the conjugated structure in one molecular unit and maintaining the electrochemical activity [13]. Polystyrene sulfonate was grafted with azo moiety in order to get photo-illuminated film through the isomerization of the azo group [14]. In the present work, oxadiazole and triazole monomers containing azo moiety as a side group were prepared.…”