Template polymerization of poly(2-methacryloyloxyethyl methacrylate)s (number-average molecular
weight: 3.47 × 104, an average number of vinyl group in molecule: 163.4) prepared from poly(2-hydroxyethyl
methacrylate) was carried out by using a copper-mediated atom transfer radical polymerization (ATRP). When
the concentration of poly(2-methacryloyloxyethyl methacrylate) was less than 0.31 wt %, the polymerization
was limited in the molecule and proceeded in a living manner at 25 °C. An apparent polymerization rate, 5.0 ×
10-5 s-1, which was very close to that of the copper-mediated ATRP in bulk, indicates that the vinyl groups were
highly concentrated in the molecule. The intensity of ethyl group detected by 1H nuclear magnetic resonance
spectroscopy drastically decreased by polymerization, the gel permeation chromatography peak shifted to lower
molecular weight side, and the dependence of solution viscosity on share rate was increased. These suggested
that the ladderlike molecule was formed by the template polymerization. Glass transition temperature of ladderlike
molecule measured by differential scanning calorimetry was observed at 210 °C.
In order to investigate the propagation of polymerization in the template with linear polymer chain, ATRP of methacryloyl type multi-vinyl monomers of pol(2-hydroxyethyl methacrylate) backbone with and without styryl groups on the chain ends was carried out. Change of hydrodynamic radii of products and conversion of vinyl group were analyzed by GPC and FT-IR, respectively.When the multi-vinyl monomer concentration was less than 0.3 wt%, gelation was completely hindered. The kinetic plots of polymerization of multi-vinyl monomers with and without styryl group on the chain ends agreed well.
Thin layer surface templates were fabricated by spin coating two immiscible polymers onto a photoreactive substrate, followed by photoirradiation and removal of the unreacted polymer with solvent. Phase-separation occurs during the spin coating process and the separated structure was tethered onto the substrate surface by photoirradiation, to yield a thin surface pattern on the substrate. The surface patterns thus obtained were robust, applicable to large areas, and could be tuned at will by designing component polymers.
The functional design of the smart electronic nose using polymer-film coated quartz resonator gas sensors, based on the solubility parameter of sensing membrane and gases, is carried out in order to develop the sensor with excellent selectivity and high sensitivity for harmful gases such as toluene, acetaldehyde and ammonia gases. The polymer-films such as propylenebutyl, poly-carbonate and acrylic-resin of which the solubility parameter almost coincide with that of toluene, acetaldehyde and ammonia gases, respectively, are chosen as a sensing membrane material coated on the quartz resonator. It is found that propylene-butyl-flim coated quartz resonator gas sensor exhibits a high sensitivity and an excellent selectivity for toluene and p-xylene gas, as it is expected from the functional design based on the solubility parameter. It is also found that poly-carbonate-flim coated sensor and acrylic-resin-film coated sensor exhibit high sensitivity and excellent selectivity for acetaldehyde and ammonia, respectively, as it is also expected. The results strongly suggest that the solubility parameter is effective to functional design of the sensing membrane of quartz resonator gas sensors. The identification of gas kind is successfully possible by the principal component pattern recognition analysis ofthe transient responses ofthe each sensor for gases.
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