This report introduces the fabrication method of a self vertically-aligned (VA) liquid crystal (LC) cells (S-VA cells) by exposure of unpolarized ultraviolet (UV) to the cells including mixtures of the LC material and the monomers carrying alkyl group. The monomers for inducing the vertical alignment with high long-term reliability were also focused on here. First, the mixture of the LC material and the monomer was injected into the empty cell without forming a conventional alignment layer on substrates. The UV was then exposed to the cell from the normal direction, and then the self vertical alignment was obtained due to formation of the self-aligned layer (SAL). Two monomers for the S-VA cells were developed, acrylic acid 4’-octyloxy-biphenyl-4-yl ester (AOBE) and acrylic acid 4-(4’-octyloxy-biphenyl-4-yloxy)-butyl ester (AOBBE). The monomer AOBE induced the vertical alignment by the exposure of the UV without addition of a radical-produced monomer since AOBE generates the radicals by the photo-Fries rearrangement. However, voltage holding ratio (VHR) was seriously decreased by the exposure of the UV, and the S-VA cell fabricated by the monomer AOBE showed low level of long-term reliability under backlight exposure. On the other hand, the monomer AOBBE needs the radical-produced monomer for obtaining the vertical alignment because AOBBE does not generate the radicals by the photo-Fries rearrangement. The monomer 1,2-bis-(4-methacryloxy-phenyl)-2,2-dimethoxy-ethane-1-one (BMPDEO) was used as the radical-produced monomer. The VHR was maintained relatively high level by the exposure of the UV, and the S-VA cells fabricated by the monomers AOBBE and BMPDEO showed high level of long-term reliability.

Bi-containing polymer films with a network structure were prepared through radical photopolymerization of liquid mixtures of monomers, which consisted of 2-carboxyethyl acrylate (2CEA) and a monomer derived in situ from BiPh3 and 2CEA. The cured films had good transparency, and their refractive indices (n_D) increased with the Bi content, reaching up to 1.58. The X-ray absorption ability of the cured films also increased with the increase of Bi content and was higher than that of aluminum.

To achieve high-speed and low-loss signal communication and processing, low dielectric insulating materials have attracted much attention. In this study, the dielectric properties of an aromatic poly(thioether) containing triphenylphosphine sulfide moieties were investigated. Its dielectric constant (ε) and dielectric dissipation factor (tanδ) are 3.15 and 0.0045, respectively, which are lower than those of the corresponding P = O group-containing poly(thioether) (ε = 3.29 and tanδ= 0.0065). These results are probably due to the less polar nature of the P = S group compared to the P = O group, which reduces the atomic/orientational polarization components. On the other hand, the dielectric properties of the P = S groupcontaining poly(thioether) are higher than those of the P = S group-containing poly(ether) (ε = 2.99 and tanδ = 0.0038) because the thioether moieties have a larger electron polarization component compared to the ether moieties.

The ring-opening polyaddition between 5-membered cyclic carbonate and polyetheramine with α-methyl group at room temperature using 1,5,7-triazabicyclo [4.4.0] deca-5-ene (TBD) as catalyst was investigated. The reaction of monofunctional 5-membered cyclic carbonate with bifunctional polyetheramine having α-methyl groups proceeded via ring-opening addition to form polyether bearing hydroxyurethane moiety at room temperature by the addition of 30 mol% of TBD. Based on the model reaction, polyaddition with a bifunctional five-membered cyclic carbonate was performed to oligomers with a M_n of about 6900 g/mol. Furthermore, networked polymers bearing hydroxyurethane linkage were synthesized by the polyaddition of bifunctional five-membered cyclic carbonate with trifunctional polyetheramine with α-methyl groups.

The CCL (copper clad laminate) used in 5G communication millimeter-wave requires both low dielectricity(D_f , D_k) and high Tg (heat resistance). There is a trade-off relationship between low dielectric and heat resistance, however there no materials available that simultaneously satisfy both of these properties. Therefore, before the curing, multiple monomers and inorganic fillers are blended in the varnish solution. Be that as it may, the mixture of a plurality materials does not satisfy the compatibilities well, it is not an effective method. For this compatibilities issue, block type polymer linking with some functional units by chemical bond has been proposed. In this paper, we first analyzed the polymer units that have played significant role diverse properties in the CCL fields. Based on this analysis, the next step was to design a block type polymer in which Isobornyl methacrylate and 1,2-polybutadiene units are chemically bonded to contribute low dielectricity and heat resistance. We confirmed and explained these effects and discussed the excellent materials for CCL.