The optoelectronic properties of polymeric semiconductor materials can be utilized for the fabrication of organic electronic and photonic devices. When key structural requirements are met, these materials exhibit unique properties such as solution processability, large charge transporting capabilities, and/or broad optical absorption. In this review recent developments in the area of π-conjugated polymeric semiconductors for organic thin-film (or field-effect) transistors (OTFTs or OFETs) and bulk-heterojunction photovoltaic (or solar) cell (BHJ-OPV or OSC) applications are summarized and analyzed.

π-Conjugated Polymers for Organic Electronics and Photovoltaic Cell Applications†

In this Feature Article, we discuss recent developments of flame retardant polymers. Three approaches are considered: (i) inherently flame retardant polymers, (ii) chemically modified polymers and (iii) flame retardants as additives for polymers. We have tried to show the new directions and concepts emerging in the field of flame retardancy. We have mainly focused our comments on flame retardants, nanofillers and surface treatment because very promising concepts appeared recently in the published literature. Synergistic aspects are also fully discussed.

Fire retardant polymers : recent developments and opportunities

This paper traces the historical development of high temperature resistant rigid-rod polymers. Synthesis, fiber processing, structure, properties, and applications of poly(p-phenylene benzobisoxazole) (PBO) fibers have been discussed. After nearly 20 years of development in the United States and Japan, PBO fiber was commercialized with the trade name Zylon® in 1998. Properties of this fiber have been compared with the properties of poly(ethylene terephthalate) (PET), thermotropic polyester (Vectran®), extended chain polyethylene (Spectra®), p-aramid (Kevlar®), m-aramid (Nomex®), aramid copolymer (Technora®), polyimide (PBI), steel, and the experimental high compressive strength rigid-rod polymeric fiber (PIPD, M5). PBO is currently the highest tensile modulus, highest tensile strength, and most thermally stable commercial polymeric fiber. However, PBO has low axial compressive strength and poor resistance to ultraviolet and visible radiation. The fiber also looses tensile strength in hot and humid environment. In the coming decades, further improvements in tensile strength (10–20 GPa range), compressive strength, and radiation resistance are expected in polymeric fibers. Incorporation of carbon nanotubes is expected to result in the development of next generation high performance polymeric fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 100: 791–802, 2006

Rigid-rod polymeric fibers

http://csmres.co.uk/cs.public.upd/article-downloads/pasquali.pdf

Carbon nanotube-based neat fibers

Electrospinning is a rapidly growing polymer processing technology as it provides a viable and simple method to create ultra-fine continuous fibers. This paper presents an in-depth review of the mechanical properties of electrospun fibers and particularly focuses on methodologies to generate high strength and high modulus nanofibers. As such, it aims to provide some guidance to future research activities in the area of high performance electrospun fibers.

/pdf/high-strength-and-high-modulus-electrospun-nanofibers-372b80mpqm.pdf

E. Won Choe

Papers

Synthesis, spinning, and fiber mechanical properties of poly(p-phenylenebenzobisoxazole)