Abstract
The secondary structure of poly(γ-benzyl L-glutamate) (PBLG) with degrees of polymerization over 18 is dominated by α-helical conformation. POSS-end-capped PBLG polymer has been reported to exhibit nanoribbon self-assembly structure. In this work, we introduce Rhodamine B (RhB) fluorophore to the end of POSS-PBLG-RhB to form a doubly end-capped POSS-PBLG-RhB polymer. The effect of the hydrophilic RhB fluorophore at the chain end to the intramolecular hydrogen bonds of α-helical PBLG block are observed by self-assembling POSS-PBLG-RhB in three chosen solvents including acetone, chloroform and toluene. α-Helical structure of PBLG block can be maintained in chloroform and toluene, but is transformed into mixtures ofα-helical and β-sheet conformations in acetone, which are verified with the measurements of Fourier Transform Infrared spectroscopy (FT-IR). Under the excitation at 365 nm and 532 nm, POSS-PBLG-RhB nanoparticles exhibits two-band emission in three solutions, but the emission from aggregation of POSS-PBLG blocks are not strong enough to decrease the yellow light from RhB. The self-assembly structures of of POSS-PBLG-RhB in the three solvents in different time are also observed by Transmission Electron Microscopy (TEM). The relationship between the solvents properties and the observed self-assembly structures are discussed.