Takakazu Kojima

Role of substituent in electrooxidation of poly(1-substituted pyrrole) films

Poly(1-substituted pyrrole)s were prepared on a platinum electrode with different electrolysis times, and their properties were studied by cyclic voltammetry. The oxidation potential for most of the poly(1-alkylpyrrole)s were almost 0.3 V versus the Ag/Ag + reference electrode, except for poly(1-butylpyrrole). The electron transfer rate in polymer films depends on the electrolysis time and the size of the substituent. The difference of the redox peak potential of poly(1-phenylpyrrole) was smaller than that of poly(1-anisylpyrrole) films. The role of a substituent in the electrochemical behavior of the polymer main chain is discussed.

Iridescence of 2-hydroxyethyl methacrylate/aromatic allyl ester Reaction mixtures

Reaction of 2-hydroxyethyl methacrylate and diallyl phthalate or vinyl 4-tert-butylbenzoate has been found to give an iridescent reaction mixture. Transmittance spectra of the reaction mixture depended on the temperature in the range of 0 to 60°C. The temperature-transmittance curves showed a discrete stepwise change near the room temperature. Polymerization reaction of 2-hydroxyethyl methacrylate (PHEMA) in a nonreactive monomer substitute, dipropyl phthalate, showed a temperature dependence as was seen for the iridescent reaction mixture, but was not iridescent. PHEMA suspension in several aromatic solvents also showed iridescence, and some of them were temperature dependent. The mechanism of temperature-dependent iridescence of the copolymerization reaction mixtures is discussed.