resumo
Variable chain length di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks were prepared by application of a sol-gel strategy. These materials, designated as di-urethanesils (represented as d-Ut(Y'), where Y' indicates the average molecular weight of the polymer segment), were doped with lithium triflate (LiCF3SO3). The two host hybrid matrices used, d-Ut(300) and d-Ut(600), incorporate POE chains with approximately 6 and 13 (OCH2CH2) repeat units, respectively. All the samples studied, with compositions a > n a parts per thousand yenaEuro parts per thousand 1 (where n is the molar ratio of (OCH2CH2) repeat units per Li+), are entirely amorphous. The di-urethanesils are thermally stable up to at least 200 A degrees C. At room temperature the conductivity maxima of the d-Ut(300)- and d-Ut(600)-based di-urethanesil families are located at n = 1 (approximately 2.0 x 10(-6) and 7.4 x 10(-5) Scm(-1), respectively). At about 100 A degrees C, both these samples also exhibit the highest conductivity of the two electrolyte systems (approximately 1.6 x 10(-4) and 1.0 x 10(-3) Scm(-1), respectively). The d-Ut(600)-based xerogel with n = 1 displays excellent redox stability.
palavras-chave
LINKED POLY(OXYETHYLENE)/SILOXANE ORMOLYTES; IONIC-CONDUCTIVITY; TRIFLATE; UREA; NANOHYBRIDS; EMISSION
categoria
Chemistry; Electrochemistry; Physics
autores
Goncalves, MC; Bermudez, VD; Silva, MM; Smith, MJ; Morales, E; Ferreira, RAS; Carlos, LD
nossos autores
Luís Carlos
Professor Catedrático
Maria Rute de Amorim e Sá Ferreira André
Professor Catedráticoagradecimentos
The authors acknowledge financial support from Fundacao para a Ciencia e a Tecnologia (contract POCI/QUI/59856/2004).