Light‐scattering measurements of polyacrylonitrile (PAN) prepared by aqueous suspension polymerization and solution polymerization were made in both dimethylformamide (DMF) and γ‐butyrolactone (γ‐BL). The following relations between the intrinsic viscosity [η] (in deciliters per gram) and the weight‐average molecular weight were obtained: [η] = 3.35 × 10−4 M̄w0.72 (in DMF at 30°C.) and [η] = 4.00 × 10−4 M̄w0.69 (in γ‐BL at 30°C.). The relation in DMF is in agreement with the results of many other researchers, but differs from the results of Bisschops et al. and Peebles. Analysis of the results by the recent viscosity theory reported by Inagaki et al. indicates that the steric factor σ is 2.17 on PAN in both DMF and γ‐BL. It is found that the root‐mean‐square radius of gyration of the chain measured by light scattering 〈S2〉w1/2 (LS) is in good agreement with the root‐mean‐square radius of gyration of the chain calculated by using the viscosity theory of Inagaki et al. 〈S2〉w1/2 (vis) in both DMF and γ‐BL. Relations between the root‐mean‐square radius of gyration of the chain (in Angstroms) in DMF and γ‐BL and the molecular weight were obtained: 〈S2〉w1/2 = 7.94 × 10−2 M̄w0.66 (in DMF) and 〈S2〉w1/2 = 2.19 × 10−1 M̄w0.57 (in γ‐BL). From the estimation of the second virial coefficient A2 and the value of B obtained from viscosity theory, it is found that DMF is a better solvent than γ‐BL.

ZnO films dispersed with Ag‐nanocrystals (Ag‐NC/ZnO) were fabricated by the molecular precursor method. Electrical and optical properties of the films and their application in the GaInN‐based blue LEDs were studied through the observations of photoluminescence (PL) spectra and analytical simulations. Although the enhancement of the blue LED emission could not be observed, the PL spectra exhibited additional emission peaks in the yellow spectral region. Judging from their spectral shape, near‐band‐edge emissions were found to be replicated by the local surface plasmon resonances.

synopsisQuantitative determination of endgroups in an acrylonitrile-methyl acrylate (90 : 10) copolymer polymerized with NaC10a-Na&30a redox system in aqueous solution was carried out by conductometric and dyeing methods for SOaH incorporated into polymer, x-ray analysis for S in polymer, and polarography for C1 in polymer. The number-average molecular weight was measured by osmometry. Determination of endgroups was done on both unfractionated polymer and fractionated polymer. On the average, 0.95 mole S and 0.71 mole SOaH per molecule were found in unfractionated polymer. For fractionated polymer, 0.68 mole S and 0.69 mole SOaH per molecule were found. A small amount of C1 was also found in both unfractionated polymer and fractionated polymer. The difference between results for the two polymers and polymerization kinetics are d i s CUSSed.

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