Amphiphilic diblock copolymers containing glycopolymer segments, polystyrene block poly[2 ( β D glucopyranosyloxy)ethylacrylate](PS b PGEA), were synthesized by atom transfer radical polymerization. The morphologies of the crew cut aggregates of PS b PGEA in water were studied by TEM. It has been found that for one specific diblock copolymer, the morphological transformation from spheres to vesicles was controllable by changing solvents. Spheres, rods and vesicles were found to be the dominant morphologies for PS 55 b PGEA 9 when the solvents were DMF, DMF/1,4 doxane and 1,4 dioxane respectively. When same solvent, e.g . 1,4 dioxane, was used, sphere to vesicle transition of crew cut aggregates was also obtainable by using diblock copolymers of different compositions. The copolymers with a higher hydrophilic segment content tend to form spheres, while those with a lower content yield predominated vesicles.
Bismaleimides bearing electron-donating chromophore moieties, A (=)-D (*)-A (=) type monomers, i.e. N,N-bis(4-maleimidophenyl)methylamine (BMIPMA), N,N-bis(4-maleimidophenyl)aniline(BMIPA) and 2,5-bis(4-maleimido phenyl)-1,3,4-oxadiazole(BMIPODA) as well as their corresponding saturated model compounds, i.e. N,N-bis(4-succinimidophenyl)methylamine( BSIPMA), N,N-bis(4-succinimidophenyl)aniline(BSIPA) and 2,5-bis(4-succimidophenyl)-1,3,4-oxadiazole (BSIPODA) were synthesized. It was found that the fluorescence quantum yields of A (=)-D (*)-A (=) monomers were always dramatically lower than those of their corresponding saturated model compounds. These A (=)-D (*)-A (=) bismaleimides possess a strong SSQE, which is attributed to an intramolecular charge transfer interaction.
An EVAl membrane with polyionic complex (PIC) as a skin layer has been prepared by in situ polyionic complexation between the cationically modified surface of EVAl membrane and the corresponding polyanion solutions.Two types of polyanions like sulfonated EVAl and phosphorylated EVAl,as well as quaternary ammonium modified EVAl membrane were synthesized and used for polyionic complexation.To reach the complete complexation,the amount of polyanion must be well above the cations on the surface of EVAl.The x ray photoelectron spectroscopy and elemental analysis revealed that the complexation mainly occurred on the surface of EVAl membrane.An asymmetric membrane with more condensed skin layer and porous inner layer was obtained,which may find new applications in biological field.
A β-diketone-bridged chromophore-containing acrylic monomer, 1-(4-dimethylaminophenyl)-4-methyl-4-pentene-1,3-diketone(DMPDK) and its saturated model compound, 1-(4-dimethyl aminophenyl)-1,3-butanedione(DMBDK) were synthesized and investigated by spectroscopy. It was found that the fluorescence intensity of DMPDK was much lower than that of DMBDK at the same concentration, which indicates that DMPDK, a β-diketone-bridged acrylic monomer having chromophore moiety, also showed fluorescence structural self-quenching effect(SSQE). Photo-induced tautomerization of DMBDK in acetonitrile was studied by means of UV and fluorescence spectroscopy. The results imply that the fluorescence method is capable of monitoring tautomerization of some fluorescent β-diketones.
