Bo-Tau Liu

A novel method to control inner and outer haze of an anti-glare film by surface modification of light-scattering particles.

Anti-glare films with various inner haze and outer haze were fabricated by a novel and simple method to modify the surface of the light-scattering particles via an acid or base treatment. The mechanism of formation of the inner and outer haze was investigated by the morphology of the AG coating layer. When the solvent evaporated, the treated light-scattering particles easily aggregated in the AG coating layer, increasing the outer haze and decreasing the inner haze. XPS analysis revealed that this result may have resulted from partial removal of the stabilizers on the light-scattering particles by the acid or base treatment. In this study, we demonstrated that the ratio of outer haze to inner haze varied from 0.32 to 3.14 with the same relative composition of particle, resin, and solvent in the AG coating; this ratio could be controlled by adjusting the proportion of untreated particles to treated particles.

Conductive polyurethane composites containing polyaniline-coated nano-silica

In this study, we used 1.2-Aminopropyltriethoxysilane (APTS) as a coupling agent to synthesize silica-polyaniline (PANI) core-shell nanoparticles. The core-shell nanoparticles and PANI oligomers were reacted with isocyanates to prepare the conductive polyurethane (PU)-PANI-silica nanocomposites. The core-shell-nanoparticle structure shows significant enhancement on electrical properties of the conductive nanocomposites even though only 0.0755-wt.% PANI was coated on the nano-silica. The surface resistance of the nanocomposite containing 5 wt.% PANI can reduce to ~10(8) Ω/sq, lowering two orders in contrast to the nanocomposite without the core-shell structure. In comparison with the neat PU, tensile strength and elongation of the nanocomposite containing silica-PANI core-shell nanoparticles can increase 3.1 and 3.8 times, respectively. We suspect that the extraordinary enhancement of electrical and mechanical properties may result from the fact that contact probability among PANI moieties and chemical bonding between particles and PU matrix increase due to the PANI coated on the surface of silica.

Anti-scratch and transparency properties of transparent conductive carbon nanotube films improved by incorporating polyethoxysiloxane.

Transparent conductive films of single-walled carbon nanotubes (SWCNTs) were fabricated by a simple method to significantly enhance anti-scratch and transparency properties by the incorporation of polyethoxysiloxane (PES). The reasons for changes in the mechanical properties and transmittance were investigated through the reflection property and morphology of thin films. With the incorporation of PES, the sheet resistance of the SWCNT thin film remained unchanged after the anti-scratch test. It was found that the transmittance of the thin films suddenly increased when the thickness of the PES layer was ca 100 nm. Although the PES incorporation resulted in a slight increase in the sheet resistance, the experimental results revealed that the sheet resistance of the SWCNT thin films with PES was lower than that of films without PES for the same transmittance due to the increase of the transmittance caused by the PES incorporation. We have demonstrated that the sheet resistance was halved at a transmittance of ∼86% due to PES incorporation. SWCNT thin films with PES showed better electrical properties than those without PES after a bend test.

Effect of eccentricity on the electroosmotic flow in an elliptic channel.

The electroosmotic flow in an elliptic channel having constant surface potential (CSP) or charge density (CSCD) is considered at low potential and arbitrary double layer thickness. Analytical expressions for the flow velocity and the corresponding asymptotic results for thick double layers that are readily applicable to experimentalists are recovered. For the range of salt concentration usually encountered in practice, the mean flow velocity for the case of CSP differs both quantitatively and qualitatively from that for the case of CSCD. Using an equivalent circular channel to simulate an elliptic one is inappropriate, in general, neither is assuming electroneutrality on the channel axis even when double layer is ca. 1/3 of the equivalent channel radius.

Solving EDL configuration near a dissimilarly charged protrusions surface model using perturbation method.

In this work, an elementary, novel dissimilarly charged protrusions (DCP) surface model in an electrolyte solution considering simultaneously the complexity of both surface morphology and surface charged condition, which are concerned frequently on a biological cell membrane, on a modified micro-particle surface, or in a lab-on-a-chip biosensor device, is proposed. Based on Fourier series and the perturbation technique, the configuration of electrical double layer (EDL) near this complicated charged surface model is successfully solved semi-analytically. The numerical calculation reveals that, the methodology suggested in present study could deal with charged surface systems of arbitrary geography and of arbitrary charge distribution. In the analysis, three special subjects are discussed, including an isolated dissimilarly charged protrusion, the effect of protrusions, and the effect of dissimilarly charged condition on protrusions.

EDL configuration on a dissimilarly charged protrusion array via double Fourier series and perturbation method.

In this study, through the extension of an one-dimensional, dissimilarly charged protrusions surface model set up in our previous work, a novel dissimilarly charged protrusion array (DCPA) model immersed in an electrolyte solution, which could simulate realistically both the surface morphology and the surface charged condition profoundly concerned on a biological cell membrane, or on the surface of a micro-scale, modified particle used in biomedical engineering and water treatment, is proposed. Considering the condition of small protrusions, the electrical potential field due to the electrical double layer (EDL) on DCPA model is solved semi-analytically using both the double Fourier series and the perturbation method. The analysis from the numerical result reveals that, a small, dissimilarly charged protrusion can lead to a steep variation in the local EDL configuration, especially compared with that in the condition when the charged surface is taken roughly as a flat surface using a lumped, mean surface charge density.