Study of the diffusion of pyrene in silicone polymer coatings by steady state fluorescence technique: effects of13; pyrene concentration

Anandan, C and Basu, Bharathibai J and Rajam, KS (2004) Study of the diffusion of pyrene in silicone polymer coatings by steady state fluorescence technique: effects of13; pyrene concentration. European Polymer Journal, 40 . pp. 1833-1840.

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    Abstract

    The concentration dependence of the diffusion coefficient of pyrene in single component and two-component room13; temperature curing silicone polymer coatings is investigated by the steady state fluorescence technique by measuring the pyrene excimer fluorescence intensity. At pyrene concentrations lower than 10 mM, the intensity of excimer fluorescence is proportional to the concentration and at higher concentrations it deviates from this trend due to concentration quenching. Thermal aging studies show that this concentration quenching can be removed by thermal annealing and the excimer emission intensity approaches the value expected from the trend at lower concentrations. The diffusion coefficient of pyrene at low concentrations in silicone polymer coatings is obtained using the approximate solution of onedimensional diffusion equation. A modified approach is employed to estimate the diffusion coefficient at higher pyrene concentrations. In this method, the excimer intensity and time scale are shifted, respectively to Imax the maximum value of excimer intensity attained during annealing and tmax, the time taken to reach this. The estimated diffusion coefficients13; at different pyrene concentrations show a negligible dependence on pyrene concentration in both types of polymers. These results are attributed to the high structural mobility of silicone polymer chains due to their molecular structure.

    Item Type: Journal Article
    Additional Information: copyright belongs to Elsevier
    Uncontrolled Keywords: Pyrene;Silicone coatings;Diffusion coefficient;Fluorescence
    Subjects: CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
    Division/Department: Surface Engineering Division, Surface Engineering Division, Surface Engineering Division
    Depositing User: Mr. N A
    Date Deposited: 11 May 2006
    Last Modified: 03 May 2012 11:33
    URI: http://nal-ir.nal.res.in/id/eprint/1393

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