Intrinsically Conducting Polymers: An Emerging Technology
نویسندگان
چکیده
A discussion of various strategies for the intrazeolite encapsulation of polymer filaments is given. Two examples are discussed in more detail: Poly(2-ethylaniline) and pyrolyzed polyacrylonitrile in zeolite hosts. Poly(2-ethylaniline) chains were synthesized within the three-dimensional channels of dehydrated zeolites X and Y via oxidation of the intrazeolite monomers with aqueous (NH4)2S20s. The steric demands for the polymerization are illustrated by the inability of the polymer to form in the one-dimensional channel system of mordenite. Since protons are not necessary for the polymerization to occur, the polymer is formed in the acid form of the zeolites as well as in the Na-forms. The intrazeolite polymer chain length peaks at about 0.1 μπι (determined from gel permeation chromatography), and is greater than that obtained in bulk polymerizations. Intrazeolite polyacrylonitrile (PAN) was formed from preadsorbed acrylonitrile in zeolite Y and mordenite on reaction with radical initiators. Chain length analysis with gel permeation chromatography revealed a peak molecular weight of 19,000 for PAN in NaY, and about 1,000 for the polymer in mordenite. When intrazeolite PAN was pyrolyzed under nitrogen, black encapsulated material resulted that had lost the nitrile groups and hydrogen. After removal from the zeolite hosts, the pyrolyzed polyacrylonitrile showed electronic DC conductivity at the order of 10"̂ Scm'l.
منابع مشابه
Electrically conducting polymers: Materials of the twentyfirst century
The paper critically reviews some recent developments in the field of electrically conducting polymers which have grown very rapidly since the discovery that there is a very sharp increase in conductivity when intrinsically insulating organic conjugated polymers such as, polyacetylene are doped with oxidizing or reducing agents. These polymers, also called synthetic metals, combine the electric...
متن کاملAn aptasensor based on electrosynthesized conducting polymers, Cu2O–carbon dots and biosynthesized gold nanoparticles, for monitoring carcinoembryonic antigen
Current work proposes an inimitable composite, with great electrical conductivity and quite enhanced surface area, (including conducting polymers (poly (cathechol)), Cu2O–carbon dots and green synthesized gold nanoparticles) for detecting acute carcinoembryonic antigen. At current work, the electropolymerization was offered instead of enzyme-catalyzed polymerization of poly (catechol). <b...
متن کاملConducting polymer-hydrogels for medical electrode applications.
Conducting polymers hold significant promise as electrode coatings; however, they are characterized by inherently poor mechanical properties. Blending or producing layered conducting polymers with other polymer forms, such as hydrogels, has been proposed as an approach to improving these properties. There are many challenges to producing hybrid polymers incorporating conducting polymers and hyd...
متن کاملRemoval of thiocyanate ions from aqueous solutions using polypyrrole and polyaniline conducting electroactive polymers
Polypyrrole (PPy/Cl) and polyaniline (PAni/Cl) synthesized chemically onto sawdust (SD)was used for removal of thiocyanate (SCN-) ions from aqueous solutions. The effect of someimportant parameters such as pH, initial concentration, sorbent dosage, and contact time onuptake of SCN- was investigated. PPy/SD was found to be much more effective sorbent thanPAni/SD for uptake SCN- from aqueous solu...
متن کاملAdvances in sensors based on conducting polymers
Conducting polymers with a blend of interesting optical and mechanical properties can be used in situations where inorganic materials are not suitable. Synthetic capabilities as well as fabrication techniques have been developed to such an extent that molecular electronic devices based on conducting polymers can be designed, marking evolution of a sophisticated technology in the field of microe...
متن کامل