Polymerization of diiodoacetylenes, their structure and electrical properties

Janevski, Aco and Leben, Stanko and Osredkar, Uci and Sebenik, Anton (1992) Polymerization of diiodoacetylenes, their structure and electrical properties. Synthetic metals, 53 (1). pp. 21-28.

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Abstract

Polydiiodoacetylenes (PDIA) were  polymerized at different temperatures using TiCl4 AlEt3 and Ti(OBu)4 AlEt3 as catalysts. The crystallinity, concentration of unpaired spins, relaxation times, diffusion of spins, conjugations and energy gaps of the polymers were determined by X-ray diffraction, spectroscopic methods and electrical measurements. A crystalline polymer was obtained with TiCl4 AlEt3, while with Ti(OBu)4 AlEt3 an amorphous polymer was obtained. The concentration of unpaired spins for the crystalline sample was 6.7 x 1020 and 5.3 x 1020 spins/mol for the amorphous one. The energy gap for the former was 0.76 and for the latter 1.29 eV, while the electrical conductivities were 5.0x10-6and 3.9x10-9 Ω-1cm-1 respectively. The amorphous sample had no spin saturation, a lower diffusivity of spins and a lower conjugation, as compared to the crystalline PDIA. The relaxation times were measured only for the latter and were T1 = 1.189x10-5 s and T2 = 0.745x10-8 s. Both samples decomposed at 300 oC into iodine and charcoal. The stability of the PDIA against oxygen was much better as compared to polyacetylene.

Item Type: Article
Subjects: Engineering and Technology > Materials engineering
Engineering and Technology > Other engineering and technologies
Divisions: Faculty of Technology
Depositing User: Aco Janevski
Date Deposited: 15 Apr 2013 13:36
Last Modified: 15 Apr 2013 13:36
URI: http://eprints.ugd.edu.mk/id/eprint/6116

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