Attempts were made to prepare monodispersed electronic ink particles by a new procedure, in situ emulsifier-free emulsion polymerization. Highly monodispersed poly(methyl methacrylate-co-ethylene glycol dimethacrylate) electronic ink particles containing blue dyes and charge control additives (E-81) were successfully prepared both in aqueous medium and in a mixture of water and methanol by emulsifier-free emulsion polymerization. On increasing either the concentration of oil blue N or E-81, the particle size decreased initially but then increased in the absence of methanol, whereas particle size progressively increases in the presence of methanol. The addition of methanol in the polymerization also influences the polymerization kinetic and the charge density of electronic ink particles. The resulting electronic inks were found to be smooth on the surfaces and particle sizes were 300-700 nm with a coefficient of variation of 0.3%. Electrophoretic mobility of the resulting electronic ink was -2.08 to -5.28 × 10 -5 cm 2 /V‚s in the presence of charge control additives.

Polymeric particles ranging in diameter from 1 to 3.5 µm containing a black dye, Sudan black B, were prepared by dispersion polymerization in a methanol and water mixture. To control their electrophoretic mobility, a varying amount of charge control additives was added after first labeling them with a fluorescent moiety to trace their distribution by confocal laser microscopy. The particle size was found to be quite sensitive to both the change in polarity of the polymerization medium and the amount of polymeric stabilizer employed. At the same time, increasing the amount of charge control additives resulted in an increase in the particle size. On the other hand, the electrophoretic mobility exhibited a maximum or optimum point at ∼0.3 wt % of charge control additive. This is consistent with the fluorescence intensity profile obtained from the confocal laser measurement, which shows a decrease in the intensity of the particles with increasing concentration of charge control additives. The simple peak patterns in the cross-sectional profile obtained from the confocal laser measurement suggests that the charge control additives are mainly distributed inside of the particles.

Titanium dioxide inorganic core and polymer shell composite poly(methyl methacrylate-co-butylacrylate-co-methacrylic acid) [P(MMA-co-BA)-MAA] particles were prepared by emulsion copolymerization. Fourier transform IR (FTIR) spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering (DLS) characterized the composite particle size and size distribution. The field emission SEM (FE-SEM) results of the composite particles showed regular spherical shape and no bare TiO 2 was detected on the whole surface of the samples. The composite particles were produced, showing good spectral reflectance compared with bare TiO 2 . TGA results indicated the encapsulation efficiency and estimated density of composite particles. Encapsulation efficiency was up to 78.9% and the density ranged from 1.76 to 1.94 g/cm 3 . Estimated density of the composite particles is suitable to 1.73 g/cm 3 , due to density matching with suspending media.

Titanium dioxide core and polymer shell composite poly(methyl methacrylate-co-n-butyl acrylate-comethacrylic acid) [P(MMA-BA-MAA)] particles were prepared by emulsion copolymerization. The stability of dispersions of TiO 2 particles in aqueous solution was investigated. The addition of an ionic surfactant, sodium lauryl sulfate, which can be absorbed strongly at the TiO 2 /aqueous interface, increases the stability of the TiO 2 dispersion effectively by increasing the absolute value of the potential of the TiO 2 particles. The adsorption of the nonionic surfactant, Triton X-100, on the surface of TiO 2 particles is less than that of the ionic surfactant. Fourier transform IR spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering characterized the composite particle size and size distribution. The field-emission scanning electron microscopy results for the composite particles showed a regular spherical shape, and no bare TiO 2 was detected on the entire surface of the samples. The composite particles that were produced showed good spectral reflectance compared to bare TiO 2 . Thermogravimetric analysis results indicated the encapsulated TiO 2 and estimated density of composite particles. There was up to 78.9% encapsulated TiO 2 and the density ranged from 1.76 to 1.94 g/cm 3 . The estimated density of the composite particles is suitable at 1.73 g/cm 3 , which is due to density matching with the suspending fluid. The sedimentation experiment indicates that reducing the density mismatch between the composite particles and suspending fluid may enhance the stability.

The effect of operating temperature on performance degradation of direct methanol fuel cell (DMFCs) is examined to disclose the main parameter of the degradation mechanism and the degradation pattern in the membrane electrode assemblies (MEAs). The DMFC MEA degradation phenomenon is explained through the use of various electrochemical/physicochemical tools, such as electrochemical impedance spectroscopy, electrode polarization, methanol stripping voltametry, field emission‐scanning electron microscopy, X‐ray diffraction, inductively coupled plasma‐atomic emission spectroscopy, and X‐ray photoelectron spectroscopy analysis. The operation of DMFC under high temperature accelerates the degradation process of the DMFC. The higher degradation rate under high temperature DMFC operation is mainly attributed to the formation of membrane pinhole with interfacial delamination and cathode degradation. A high operating temperature may result in more considerable thermal and mechanical stress of the polymeric membrane continuously due to frequent dry–wet cycling mode and substantial uneven distribution of water between the anode and the cathode during a long period of DMFC operation. On the other hand, the electrochemical surface area deterioration by Pt coarsening and ionomers loss is not directly related to the larger DMFC performance decay at high temperature.