Epoxidation of surface-bound polynorbornene films on silicon: Preventing degradation via solvent effect
(4456-4462) Polymer 52 #20 (2011)
Song et al ofJilin University, China, prevented the detachment of polymer chain during the epoxidation of covalently grafted polynorbornene (PNb) films.  Surface-bound PNb was prepared by surface-initiated ring-opening metathesis polymerization (SIROMP) from Si/SiO2 substrates, and then epoxidized with meta-chloroperoxybenzoic acid by taking advantage of the double bonds along the polymer chains.   Kinetics study revealed that the surface-bound PNb is epoxidized gradiently from the surface toward the silicon substrate in ether. Through the solvent control, epoxidation of surface-bound PNb film without degradation was achieved under relatively mild condition.  (RDC 9/7/2011)

High glass transition and thermally stable polynorbornenes containing fluorescent dipyrene moieties via ring-opening metathesis polymerization
(3673–3680)Journal of Polymer Science Part A: Polymer  Chemistry 49 #17 (2011)
Liao et al of the National Taiwan University of Science and Technology and Yuan University, Taiwan, synthesized a high-glass-transition-temperature polynorbornene, poly(NBEDPY), containing chromophore groups by ring-opening metathesis polymerization (ROMP) using Grubbs' catalysts.  Poly(HNBEDPY) was obtained by the reduction of poly(NBEDPY).  The glass transition temperatures (Tg) of poly(NBEDPY) and hydrogenated poly(HNBEDPY) were as high as 250 °C and 220 °C, respectively, because of the rigid dipyrene groups, which are higher than those of commercially available ring-opened hydrogenated polynorbornenes (JSR ARTON®; 120–165 °C). The 10% weight-loss temperatures of hydrogenated poly(HNBEDPY) and poly(NBEDPY) were up to 450 °C and 400 °C, respectively. A hydrogenated poly (HNBEDPY) film showed excellent transparency (over 91%).  The photoluminescence emission spectra of poly(HNBEDPY) showed strong solvent-polarity dependence, revealing that poly (HNBEDPY) underwent remarkable bathochromic shifts with an increase in solvent polarity. Poly(HNBEDPY) also showed remarkable fluorescent solvatochromism (blue in toluene, greenish yellow in dimethyl sulfoxide). The electrochromic characteristics of poly(HNBEDPY) showed reversibility, with a color change from its green neutral form to dark red upon the application of potentials from 0 to 1.0 V.  (RDC 7/27/2011)

Preparation of neutrally colorless, transparent polynorbornenes with multiple redox-active chromophores via ring-opening metathesis polymerization toward electrochromic applications
(3248–3259)Journal of Polymer Science Part A: Polymer  Chemistry 49 #15 (2011)
Lian et al , Taiwan, synthesized  new electrochromic norbornene derivative containing triphenylamine groups (NBDTPAC8) using norbornene amine and bromotriphenylamine.  NBDTPAC8 was used in ring-opening metathesis polymerization to obtain poly(NBDTPAC8) using different Grubbs' catalysts and followed by hydrogen reduction to obtain poly(HNBDTPAC8).  The glass transition temperatures (Tg) of poly(NBDTPAC8) and hydrogenated poly(HNBDTPAC8) were 132 and 89 °C, respectively. Poly(HNBDTPAC8) film exhibited a fluorescence maximum around 416 nm with a quantum yield of up to 60%. Hydrogenated poly(HNBDTPAC8) film showed excellent transparency (up to 93%). Poly(HNBDTPAC8) showed cyclic voltammetric and electrochromic behaviors similar to those of poly(NBDTPAC8). The cyclic voltammogram of a poly(HNBDTPAC8) film cast onto an indium tin oxide (ITO)-coated glass substrate exhibited three reversible oxidation redox couples at 0.69, 0.94 and 1.38 V versus Ag/Ag+ in an acetonitrile solution. The electrochromic characteristics of poly(HNBDTPAC8) showed excellent stability and reversibility, with multi-staged color changes from its colorless neutral form to green, light blue and dark blue upon the application of potentials ranging from 0 to 1.60 V. The color switching time and bleaching time of the poly(HNBDTPAC8) film were 6.2 s and 4.3 s at 1175 nm and 6.6 s and 4.4 s at 970 nm, respectively.  (RDC 6/27/2011)