Polyacetylene optical properties

Optical properties are related to both the degree of crystallinity and the actual polymer structure. Most polymers do not possess color site units, so are colorless and transparent. But, some phenolic resins and polyacetylenes are colored, translucent, or opaque. Polymers that are transparent to visible light may be colored by the addition of colorants, and some become opaque as a result of the presence of additives such as fillers, stabilizers, moisture, and gases. 

The second method is the synthesis of copolymers or derivatives of a parent conjugated polymer with more desirable properties. This method is the more traditional one for making improvements to a polymer. It modifies the structure of the polymer to increase its processibility without compromising its conductivity or its optical properties. All attempts to do this on polyacetylene have failed as they always significantly reduced its conductivity. However, such attempts on polythiophenes and polypyrroles proved more fruitful. 

Since the optical properties of polyacetylene are highly anisotropic, the measured x is related to x/ through the relation (23) ... 

A triumph of the Durham route was the preparation of oriented crystalline polyacetylene (107-109) by stretch orientation of the polymer during the transformation reaction. This material has highly anisotropic optical properties, but the anisotropy of the conductivity of the doped polymer was low. Oriented fibers as well as films were prepared. 

Recently, there has been a great deal of Interest In semiconducting organic polymers, particularly polyacetylene ((CH) ), as electronic materials for applications where low cost and large area are important. This report first discusses the potential of organic polymer semiconductors to meet the electronic, physical and economic constraints Imposed by the photovoltaic application. Then, recent results on the structural, electrical, and optical properties of one candidate material, polyacrylonitrile (PAN), are presented. Areas for further Investigation are Indicated. 

About the same time, Alan Mac-Diarmid at the University of Pennsylvania was working with an inorganic polymer of sulfur nitride (SN)jj that also looked like a metal and raised questions about the conductivity of polymers, MacDiarmid and Shirakawa met by chance at a seminar in Tokyo, and a collaboration was begun. Because Shirakawa knew that the optical properties of a polymer change on oxidation, they oxidized polyacetylene with iodine vapor. The product was double bond had transferred to the iodine (to give I3). The result was that elec-... 

D. Comoretto, A. Borghesi, G. Dellepiane, G. Lanzani, G. F. Musso, A. Piaggi and R. Tubino, "Optical properties of highly oriented fibrous polyacetylene", to be published. 

It has been generally accepted that polyacetylene has a planar structure, irrespective of cis and trans forms, due to ir-conjugation between the sp hybridized carbon atoms in the polymer chain [1,4]. If it were possible to modify such a planar structure of pofyacetylene into a hehcal one [13], one might expect novel magnetic and optical properties [14]. Here, we report polymerization of acetylene in asymmetric reaction field constructed with chiral nematic LCs, and show that pofyacetylene films formed by helical chains and fibrils can be synthesized [15]. Polymerization mechanism giving hehcal structure from primary to higher order and hierarchical spiral morphology is discussed. 

S/cm after iodine doping and the chiral helicity of the present films should be available for novel electromagnetic and optical properties. Macroscopic alignment of helical polyacetylene has also been successfully carried out to prepare the samples that are feasible for examination of novel electromagnetic properties, which will be presented in the near feature. 

Jeon, T.-I., et al. 2005. Electrical and optical properties of polyacetylene film in THz frequency range. Carr Appl Phys 5 289. 

These dyes were then shown to sensitize photo-conductivity of poly(W-vinyl carbazole). Polyacetylene derivatives exhibit unique characteristics such as semiconductivity, high gas permeability, helix inversion, and nonlinear optical properties [253]. Attempts were made, therefore, to incorporate carbazole into polyacetylene in hope of attaining enhance properties [253]. 

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