PWA-diureasils organic-inorganic hybrids. Photochromism and effect of the organic chain length

Author(s)

Obara, P. A. ^[1] ; Sarmento, V. H. V. ^[2] ; Ribeiro, S. J. L. ^[3] ; Nalin, M. ^[3] ; Molina, C. ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP - Brazil

^[2] Univ Fed Sergipe, Dept Quim, Itabaiana, SE - Brazil

^[3] Univ Estadual Paulista UNESP, Inst Quim, Araraquara, SP - Brazil

• Document type: Journal article
• Source: Optical Materials; v. 46, p. 64-69, AUG 2015.
• Web of Science Citations: 3

Abstract

Di-ureasil organic-inorganic hybrids have been used together with Phosphotungstic acid (PWA- H3PW12O40) in the preparation of new photochromic materials. PWA was incorporated in different relative concentrations in di-ureasils displaying different organic chain lengths. The structure and photochromic behaviour of these novel material were investigated by means of infrared (FTIR), photoluminescence (PL) and Ultraviolet-Visible (UV-Vis) spectroscopies and Small Angle X-ray Scattering (SAXS) technique as a function of PWA content and also of the polymer chain length. Eu3+ has been incorporated as probe ion. For the short polymer chains, europium and PWA keggin structures are located close to oxygen in the ether type of the polyoxides segments and for the long polymer chain carbonyl groups of the urea units were observed to contribute in the coordination. Moreover, the photochromic effect was followed by UV-Vis measurements which showed that in both hybrid families changing from colorless to blue after UV exposure, and the bleaching process, depend directly on the polymer chain length and the nature of the sites where PWA are coordinated in the matrix. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/02708-8 - Photochromic hybrid films on flexible substrate obtained by sol gel process deposited by inkjet printer
• Grantee: Celso Molina
• Support Opportunities: Regular Research Grants