A new method is developed for the preparation of a transparent electrically conductive hybrid polymer films which maintain their electrical conductivity when subjected to deformation in two and three dimensions including bending, stretching and twisting. These films are made by a hybrid roll to roll (R2R) process where electrically conductive nanofibers are partially embedded in solution cast dielectric polymer films such as poly(methyl methacrylate) (PMMA), polyimide (PI) or polyurethanes (PU). Nanofibers partially embedded in films can be laser ablated to obtain in-plane anisotropic electrical conductivity created in the form of parallel conductive lines separated by non-conductive spaces on the film surface. The patterned films can be used for high resolution pixel addressable liquid crystal displays. There are several situations, such as wearable sensors, curved displays and advanced flexible OLED lightings, where elastic extensibility and/or permanent deformability are desired without significant loss of electrical conductivity. To satisfy this demand, the multifunctional films can be made elastic, thermally deformable with the judicious choice of materials comprising the nanofibers and the matrix they are embedded in. The multifunctional transparent conductive films are easily manufactured through a low-cost continuous hybrid roll to roll process. Furthermore, they can be used in future displays, solar cells, wearable electronics and skin attached sensors requiring flexibility as well as stretchability and more desirably subsequent recovery after cessation of stress and strains without any loss of electrical conductivity.
['Wei Zhao', 'Isik Isil Nugay', 'Baris Yalcin', 'Miko Cakmak']
Flexible, stretchable, transparent and electrically conductive polymer films via a hybrid electrospinning and solution casting process: In-plane anisotropic conductivity for electro-optical applications