A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.
2 May 2009 in Journal of Inorganic and Organometallic Polymers and Materials
In the present study, graphene oxide (GO) was incorporated as a nanoadditive into a polyphenylsulfone (PPSU) to develop a PPSU/GO nanocomposite membrane with enhanced antifouling properties. A series of membranes containing different concentrations (0.2, 0.5 and 1.0 wt.%) of GO were fabricated via the phase inversion method, using N-methyl pyrrolidone (NMP) as the solvent, deionized water as the non-solvent, and polyvinylpyrrolidone (PVP) as a pore forming agent. The prepared nanocomposite membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and were also characterized with respect to contact angle, zeta potential and porosity, mean pore radius, tortuosity and molecular weight cut-off (MWCO). Thermogravimetric analysis (TGA) and tensile testing were used to measure thermal and mechanical properties. The membrane performance was evaluated by volumetric flux and rejection of proteins, and antifouling properties. According to the results, the optimum addition of 0.5 wt% GO resulted in a membrane with an increased flux of 171 ± 3 Lm−2h−1 with a MWCO of ~40 kDa. In addition, the GO incorporation efficiently inhibited the interaction between proteins and the membrane surface, thereby improving the fouling resistance ability by approximately 58 ± 3%. Also, the resulting membranes showed a significant improvement in mechanical and thermal properties.