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Monodisperse cross-linked polymer microspheres with carboxyl groups on their surface were prepared by means of emulsifier-free emulsion copolymerization. The characterizations by X-ray photoelectron spectroscopy and conductometric titration indicate that most carboxyl groups are located on the surface of microspheres. Their swelling degree or cross-linking degree has been investigated by an in situ swelling method. Moreover, these microspheres can be easily and quickly self-organized into two- or three-dimensional ordered multilayer films or latex crystals. [Copyright &y& Elsevier]

A kind of fluorinated and epoxy-terminated low-molecular-weight bisphenol A polycarbonate (FBPA-PC EP) was synthesized by solution polymerization of 4, 4′-(hexafluoro-isopropylidene) diphenol (6F-BPA) with triphosgene (BTC) and further reacted with epoxy chloropropane. The structure of the polymer was confirmed by FTIR, 1 H NMR, 13 C NMR and 19 F NMR spectra. A series of negative-type fluorinated photoresists (NTFPs) were prepared by mixing of FBPA-PC EP and FSU-8 with triphenylsulfonium hexafluorophosphate and cyclopentanone as the photoacid generator (PAG) and solvent. The polymer films prepared from NTFPs by UV-curing exhibited superior chemical resistance, excellent thermal stability (Tds ranged from 295 to 303 °C) and low surface roughness. A clear negative pattern was obtained through direct UV photo-cross-linking and then chemical development which can be used as high-quality channel waveguides (the roughness of the lateral ridge ranged from 21 to 32 nm (1 × 1 μm)). For waveguides with the polymethylmethacrylate as upper cladding, the propagation loss of the channel waveguides was measured to be 0.25 dB/cm at the monitoring light of 1550 nm. [ABSTRACT FROM AUTHOR]

Abstract: A bisphenol monomer (4-methoxy) phenylhydroquinone (Me-HQ) was prepared and further polymerized with 2,2,3,3,4,4,5,5,6,6,7,7-dodeca-fluoro-1,8-octanediol (12F-diol) and decafluorobiphenyl (DFBP) to obtain highly fluorinated aromatic-aliphatic copolyethers containing methoxy groups. After demethylation and the reaction with epoxy chloropropane, a series of novel highly fluorinated aromatic-aliphatic copolyethers bearing epoxy groups (FA-APE EP) at different feed ratios of (Me-HQ)/(12F-diol) were obtained. The chemical structures of all the copolymers were analyzed by 1H NMR, 13C NMR and 19F NMR spectra. A series of highly fluorinated photoresists were prepared by composing of fluorinated copolyethers, diphenyliodonium salt as a photoacid generator (PAG) and solvent. After UV-curing, the cross-linked films exhibited excellent chemical resistance and high thermal stability (Td ranged from 230 to 278 °C). The refractive indices of the films could be controlled between 1.5127 and 1.4749 at 1550 nm by varying the feed ratio of comonomers. A clear negative pattern was obtained through direct UV exposure and chemical development. For waveguides without upper cladding, the propagation loss of the channel waveguides was measured to be 0.18 dB/cm at 1550 nm. [Copyright &y& Elsevier]

A series of fluorinated polycarbonates (AF-3OH-PC MAs) terminated by different proportions of acrylate group were synthesized and directly used as photoresist materials. The materials can directly form a cross-linked film under UV light and initiator conditions without the addition of small molecular crosslinkers. The thermal stability (Td up to 416 °C), the absorption at 1550 nm is almost zero and electro-optical stabilities (after 80 °C for 200 h, the r 33 remains 91% of the initial value) are significantly improved since the small molecular crosslinkers were not added. The propagation and insertion loss of the device were measured by a cut-back method to be only 0.66 dB/cm and 1 dB, respectively. It may be possible to have an enlightening effect on preparing electro-optical switches with better performance. Image 1 • The photoresist can be crosslinked by UV light in the presence of a chromophore. • The film also have a smooth surface, and controllable refractive indices (n = 1.495–1.533). • The photo-crosslinked films owned excellent thermal stability (T g1 = 147 °C, T d1 = 416 °C). • The electro-optical stability (r 33 remains 91% after 80 °C for 200 h) and the optical loss (0.66 dB/cm) are improved. [ABSTRACT FROM AUTHOR]