Molla Islam - Tubular or Subsurface Morphology of Octabutoxyphthalocyanine upon Self-Assembly in Polymer Matrices: Effect of the Casting Solvent.

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      Publication Details (including relevant citation   information): Islam, Molla R., Sundararajan, Pudupadi   R., Chem. - Eur. J., 2011, 17  (22), pp 6098-6108

      Abstract: Spontaneous phase-sepd., controlled   aggregate structures of photo- and electroactive mols. in polymer   matrixes are of interest for device fabrication. We show that the   self-assembly of octabutoxyphthalocyanine (Pc) in polymer   matrixes leads to tubular morphol. of Pc when the film is prepd.   with tetrachloroethane (TCE) and subsurface droplet morphol. with   chloroform. The same morphol. is seen with both bisphenol A   polycarbonate (BPAPC) and poly(Me methacrylate) (PMMA) as the   matrix. The subsurface morphol. results from the rapid assocn. of   Pc in the polymer matrix, as the film forms. With the tubular   morphol. in the films prepd. with TCE, percolation threshold is   reached with a concn. of Pc as low as 3 % (wt.) in the polymer.   Such phase-sepd. self-assembly occurs, without any annealing of   the films. Even in the absence of the polymer, Pc crystd. from   TCE also shows tubular morphol., whereas it exhibits a columnar   morphol. with chloroform. X-ray diffraction of Pc crystd. from   either solvent shows the columnar stacking of the Pc mols.   However, the morphol. is tubular when TCE is used. We attribute   the difference in the morphol. to the higher viscosity of TCE and   the diffusion-limited growth, which causes the tubular morphol.,   whereas the instantaneous self-assembly in less-viscous   chloroform leads to droplets. The solvent effect obsd. here could   be used to tailor the morphol. of such photoconductive mols. in   polymer matrixes. [on SciFinder(R)]

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