The multifunctional azopolymers (PAZ-R +*) containing azobenzene moieties with chiral group were synthesized as a new class of optical polymers.The structure of polymers was characterized by GPC, elemental analysis and circular dichroism.The optical phase conjugated responses of the polymer films were investigated by the degenerate four-wave mixing (DFWM).Furthermore, the photo-induced holographic phase gratings of the films were characterized by POM.The experimental results showed that optically active polymers(PAZ-R +*) containing chiral groups could form holographic phase gratings buried in the films.From the preliminary measurements of photoalignment, it was found that the chiral group in side-chain azobenzene polymer films could play an important role in responding polarization direction of the irradiating beams and the irradiating number.The chiral group was found to have influence on changing physical properties such as optical phase conjugated characteristics effectively and on the formation of microstructures in the film.Further studies on the photoinduced properties of side-chain azobenzene polymer films with chiral groups are in progress.
The synthesis and characterization of coil-rod-coil triblock oligomers, poly(ethylene oxide)-b-p-hexaphenyl-b-poly(ethylene oxide), are described. The number of repeating ethylene oxide units in each flexible block are 3 (EO3-PHP-EO3), 8 (EO8-PHP-EO8), 13 (EO13-PHP-EO13), and 17 (EO17-PHP-EO17), respectively. The structures of these oligomers are confirmed by 1H-NMR,13C-NMR, EA, and MALDI-TOF mass spectrometry. The introduction of soluble poly(ethylene oxide) coils to the rigid p-hexaphenyl segment significantly improves the solubility of the oligomers, so they can form smooth thin films by spin-coating from their solutions. The oligomers are quite thermally stable and have 1% weight loss temperatures at above 340℃under nitrogen. They can emit strong blue light in both solution and film state, and have fluorescence quantum yields of about 40% in chloroform. They are expected to have potential applications in optoelectronic devices.
An optically active polymer (PM1) containing azobenzene moieties with a chiral group (s-2-methyl-butyl) was synthesized by homopolymerization of monomer, 4-[2-(methacryloyloxy)ethyloxy]-4'-(s-2-methyl-1-butyloxycarbonyl)azobenzene, using the free radical polymerization method. The polymer dissolved in tetrahydrofuran (THF) could be easily processed into high optical quality films. The optical anisotropy of the polymer films was investigated by polarizing optical microscopy (POM). The experimental results showed that irradiation with a circularly polarized beam could align the orientation of the molecules in the polymer films. Moreover, the holographic phase gratings of photo-induced polymer films were detected by atomic force microscopy (AFM) and POM. In comparison with polymer containing no chiral group, it was found from the preliminary measurement of the photo-induced holographic phase gratings that PM1 containing a chiral group could form holographic phase gratings buried in the films.
The random copolymers of styrene and 2,5-bis[(4-methoxyphenyloxycarbonyl)styrene] (MPCS) with different copolymerization ratio were synthesized by conventional free radical polymerization. The copolymer having high molecular weight was experimentally elucidated using a combination of proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The liquid crystalline behavior of the copolymer was studied using differential scanning calorimetry, X-ray diffractometry and polarized optical microscopy. It was found that the liquid crystalline behavior was dependent on the content of styrene. Experimental results show that the copolymer could turn into a liquid crystalline phase at about 180°C when the content of styrene was less than 20%. The mechanical properties of the copolymer were also studied. Preliminary results indicate that the tensile strength decreases while the tensile modulus increases as the content of MPCS is increased.
A series of new optically active aromatic poly(ester amide)s containing a chiral group in the side chain prepared from the p-toluenesulfonic acid salt of o,o’-bis(leucyl)-hexanediol (TS-+LHD+TS-) and p-phthaloyl chloride and styrene-2,5- dicarbonyl chloride styrene have been synthesized by interfacial polymerization. The structure of the monomer is elucidated by FT-IR and elemental analysis. The thermal properties of the polymers were studied by DSC and TGA. The chiroptical properties of the above polymer have also been studied by circular dichroism (CD) spectroscopy. Results indicated that these polymers form helical structures.
A side-on liquid crystalline monomer, 2,5-bis[(4-hexyloxyphenyl)oxycarbonyl]styrene) (HPCS), was successfully polymerized via atom transfer radical polymerization (ATRP). The polymerization was catalyzed by CuBr/PMDETA in chlorobenzene at 90℃ with (1-bromoethyl)benzene as the initiator. The polymers have narrow MWD. It is the second example of mesogen-jacketed liquid crystalline polymer (MJLCP) prepared by ATRP.
It is reported report herein the synthesis and characterization of a new mesogen-jacketed polymer containing an electron deficient oxadiazole unit __ poly{2,5-bis[(5-tert-butylphenyl)-1,3,4-oxadiazole]styrene} (BBPOS).BBPOS can be dissolved in THE,CHCl-3,xylene,and DMSO.The structure of the monomer and the polymer was confirmed by elemental analysis,NMR,MS and GPC.The optical and electronic properties of the polymer were investigated by UV-Vis absorption spectroscopy and photoluminescence spectroscopy.The results show that the polymer films emit greenish-blue light (λ max =390 nm) upon UV excitation.Thermo-analysis showed that the glass-transition temperature of the polymer is at 117℃.Moreover,its weight loss was less than 5% on heating to about 349℃ under nitrogen atmosphere.
