Dendrimer Generation Effects On The Photophysical Properties Of Poly (aryl Benzyl Ether) Dendrictic Zinc (Ⅱ) Phthalocyanines And The Dendritic Phthalocyanines-loaded Polymeric Nanoparticles

In this paper, effects of dendrimer generation on intramolecular electron transfer and energy transfer in poly(aryl benzyl ether) dendrictic zinc(II) phthalocyanines with terminal cyano and carboxylic acid functionalities were studied by ultraviolet spectroscopy, steady fluorescence spectrometry and time-resolved fluorescence spectrometry. It was found that, dendritic phthalocyanines were mainly monomer in common organic solvent. Fluorescence lifetimes and quantum yields of poly(aryl benzyl ether) dendrictic phthalocyanines decreased obviously with an increase in the generation. The fluorescence of five dendritic phthalocyanines was quenched by addition of anthraquinone and methyl viologen (MV2+) through electronic transfer. The Ksv decreased with the increase of the generation.Studied on the intramolecular energy transfer in first and second generation of poly(aryl benzyl ether) dendritic zinc(II) phthalocyanines with terminal cyano-group by fluorescence spectroscopy and UV/Vis.The two fluorescence quantum yields (ΦENT) were basically consistent through steady fluorescence spectrometry and time-resolved fluorescence spectrometry. TheΦENT increased with an increase in the generation. The value ofΦENT for G2-ZnPc(CN)16 was determined to be 0.88, which meant that these dendritic phthalocyanines were high-efficient light-harvesting system.The interactions of two different surfactants (cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfte(SDS)) and these water-soluble phthalocyanines (ZnPc(COOH)4,G1-ZnPc(COOH)8 and G2-ZnPc(COOH)16) were studied. It was found that, these water-soluble phthalocyanines were mainly monomer with addition of CTAB. We also studied the aggregated behaviors of these water-soluble phthalocyanines varies upon interactions with CTAB by Zetasize particle size analyzer. The results show that, average sizes of micelles increased with the increased of the concentration of CTAB. The fluorescence of ZnPc(COOH)4 was quenched by SDS through dynamic quenching process because of its small steric. Otherwise, UV/Vis spectra of G1-ZnPc(COOH)8 and G2-ZnPc(COOH)16 did not change with addition of SDS.The critical micelle concentrations (CMC) of PLL-PEG-PLL was determined by using UV/Vis absorption spectrophotometer and pyrene fluorescence probe spectrometry. The self-assembled behaviors were investigated under the different initial concentration of block copolymers. The morphologies of aggregates changed from cocoon-like to sphere with the increase of the concentration of PLL-PEG-PLL. Polymeric nanoparticles between the PLL-PEG-PLL and G1-ZnPc(COOH)8 and G2-ZnPc(COOH)16 were formed via electrostatic interaction, respectively. The morphologies and photophysical properties of polymeric nanoparticles loaded with dendritic phthalocyanines were studied by AFM,TEM,UV/Vis and fluorescent spectrometer. The result showed that, TEM indicated the diameters of G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m were in the range of 33 nm-147 nm, increasing with the increase of the concentration of PLL-PEG-PLL. And morphologies of G2-ZnPc(COOH)16/m changed from cocoon-like to sphere with the increase of the concentration of PLL-PEG-PLL. It was found that, the fluorescence intensity of polymer nanoparticles were higher compared with free dendritic phthalocyanines.