Xingbo Chen

Novel photoactive hyperbranched poly(aryl ether)s containing azobenzene chromophores for optical storage

Two novel hyperbranched poly (aryl ether)s with azobenzene moieties in both the main chain and side chain of the branched arms were prepared by using B3 + A2 methodology via a nucleophilic aromatic substitution polycondensation. Structures of the hyperbranched poly (aryl ether)s with azobenzene moieties (azo-HPAEs) were characterized by means of IR, UV-visible, 1H NMR spectroscopy, and XRD. It is shown that both the azo-HPAEs exhibit high glass transition temperatures (Tg), excellent thermal stability and homogeneous photochromic behavior. By exposing their spin-coating films to an interference pattern of laser beam, both the azo-HPAEs could be used for rapid (within 30 s) fabrication of surface-relief gratings (SRGs). The obtained SRGs present no shape changes even at temperatures up to 200 °C. Especially, the azo-HPAE with azobenzene moieties in the side chain shows larger photoinduced birefringence intensity and better reversible optical storage than the one with azobenzene moieties in the main chain upon irradiation with 532 nm Nd:YAG laser. The novel azo-PAEs are photoactive to UV light (355 nm), making them potentially useful for high density information storage.

Fabrication of fluorescent holographic micropatterns based on azobenzene-containing host-guest complexes.

On the basis of photoinduced surface relief gratings (SRGs) with fluorophore/azo-complexes, a novel and facile method for fabricating stable and bright fluorescent two-dimensional micropatterns, whose color could be easily adjusted by changing the corresponding fluorophores, was developed for the first time.

Synthesis and Properties of Poly(Aryl Ether Ketone) Copolymers Containing 1,4‐Naphthalene Moieties

Abstract The new monomer 1,4‐bis (4‐fluorobenzoyl) naphthalene was synthesized using the Friedel–Crafts acylation reaction of 1,4‐naphthalenedicarboxylic acid chloride with fluorobenzene. Poly(aryl ether ketone) copolymers possessing various compositions of 1,4‐naphthylene and 1,4‐phenylene moieties were prepared by the reaction of hydroquinone (HQ) with 1,4‐bis(4,4′‐fluorobenzoyl) naphthalene (1,4‐BFN) and 4,4′‐difluorobenzophenone (DFB) in the presence of sodium carbonate and potassium carbonate in diphenyl sulfone (DPS). Thermal analyses of the copolymers showed that the glass transition temperature increased, while the melting temperature and 5 wt% loss temperature decreased with the increase of 1,4‐naphthalene moieties. For the copolymer synthesized with the molar fraction of 1,4‐BFN in the difluoro monomers (1,4‐BFN, DFB) being over 0.1, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of 1,4‐BFN, not being higher than 0.4, is rhombic. The poly(aryl ether ketone)s copolymers were soluble in polar aprotic solvents step by step for the molar fraction of 1,4‐BFN being over 0.4.

Photoactive Poly(aryl ether)s containing azobenzene moieties on pendants for fabrication of thermal stable surface relief gratings

A series of azobenzene functionalized poly(aryl ether) copolymers(azo-PAEs) containing azo moieties on pendants was prepared by direct copolymerization. The amount of azobenzene chromophores could be controlled by the feed ratio of azo-monomer. Their chemical structures and properties were characterized by means of infrared(IR) spectrometry, UV-Vis, hydrogen nuclear magnetic resonance(1H NMR), difference scanning calorimetry(DSC), and thermogravimetric analysis(TGA). The results suggest that azo-PAEs had high glass transition temperatures(Tgs) and good thermal stability. By exposing their spin-coated films to an interference pattern laser beam, azo-PAEs could be used for the fabrication of thermal stable surface relief gratings(SRGs).

Dynamics of the photo-induced orientation and relaxation of a novel hyperbranched poly(aryl ether) containing azobenzene groups

A novel hyperbranched poly(aryl ether) containing azobenzene moieties (azo-HPAE) as a side chain has been synthesized and investigated on the temperature dependence of photo-induced birefringence. Typical curves of photo-induced birefringence were obtained at 25, 40, 60, 80, and 100°C. The curves for buildup and decay of birefringence were fitted well with bi-exponential functions. The dependence of the fitted time constants on the temperature was also discussed.