PLASTICIZATION OF (PVK) POLY(N- VINYLCARBAZOLE) TO IMPROVE PROCESSING AND FABRICATION OF COMPOSITE PHOTORECEPTORS
Original Publication Date: 1977-Oct-31
Included in the Prior Art Database: 2004-Mar-31
Xerox Disclosure Journal
A method for (1) minimizing strain buildup in a composite PVK structure and (2) a method to avoid adhesion failure, is disclosed. Presently the recommended way in the art of forming the PVK layer, as a charge transport layer, in an active matrix multilayered photoreceptor structure is by solvent casting. The strain buildup in the system due to drying is sufficient when combined with the strain in the selenium layer, i.e., charge generation layer of the active matrix photoreceptor, due to its conversion to strip the selenium and PVK layers from the substrate. The instant invention involves plasticizing PVK to improve its fabrica-tion, crazing and mechanical properties while maintaining the desired electrical characteristics, It is proposed that low molecular weight (Mw6 4500) PVK be added to high molecular weight (Mw 1.5 x 10 ) PVK in successive amounts to decrease its glass transition. By lowering the glass transition to 200°C in an active matrix photoreceptor configuration, it is disclosed that strain can be relieved in the PVK layer. An added advantage is that this temperature is below the melting point of selenium (217°C) and will not disturb the selenium's morphology. The glass transition of PVK is normally 227°C. Dissimilar polymers to PVK, which are electrically poly-ethylene pyrenyl succinate, polyethylene carbazole succinate and polyethylene l,2-benzanthracene succinate. These polymers would have to be of a low molecular weight in order to be effective. It is suggested that the improvements are annealing, improved processing, improved fabrication con-ditions and improved flexibility.