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A novel photoinduced luminescence film has been prepared by immobilizing pyrene on a quartz plate surface via a flexible long spacer. The film shows combined monomer and excimer emission of pyrene both in wet and dry states, and the excimer may be formed mainly by direct excitation of ground-state dimers and/or monomers in aggregates. Classical Birks' scheme plays a little role in the formation of the excimers. The emission of the film is sensitive to the presence of dicarboxylic acids, including ethanedioic acid, malonic acid, succinic acid, etc. The emission in the monomer and excimer region increases with addition of the acids. The time needed for the emission to reach equilibrium depends on the nature of the acids. It has been shown that the longer the chains of the acids, the more time is needed. This observation is explained by considering the conformational reorganization of the immobilized pyrene due to insertion of the dicarboxylic acids into the space between neighboring spacers. Experimental results from similar studies using formic acid and acetic acid are in support of this explanation. Furthermore, the response of the film to dicarboxylic acids is reversible.

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PAM/TiO 2 composite microspheres with hierarchical surface structures were synthesized by the reaction between tetrabutyl titanate (TBOT) located within porous polyacrylamide (PAM) microgels and water in a moist atmosphere. The morphology and composition of the composite microspheres were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FI-IR), X-ray diffraction (XRD), N 2 absorption analysis, and mercury porosimetry, respectively. The results indicated that the composite microspheres, with different hierarchical surface morphologies, could be obtained by controlling the cross-linking degree of the porous PAM microgels, the relative humidity of the gas phase, the amount of residual impregnation liquid, and the TBOT concentration in the porous PAM microgels. Although the surface morphologies of the composite microspheres are varied, the morphologies are typically divided into three categories: (1) wrinkled surfaces covered with large dense TiO 2 particles; (2) porous structures sparsely suffused with large TiO 2 particles along the fringes and inner walls of the porous channels; and (3) macroporous surfaces with small TiO 2 particles distributed ubiquitously. The incorporation of TiO 2 particles into PAM microgels resulted in an obvious increase in specific surface area, and the pore size distribution of the microspheres depended strongly on the size of TiO 2 particles. The method described herein provides a potential way for finetuning the morphology and surface property of composite microspheres. Additionally, this method can be used to fabricate various composite materials through altering the precursor and/or polymeric microgel template.