Formation of a host nanostructure for ferroelectric liquid crystals using thiol-ene polymers

Abstract

Liquid crystal displays are a subject of intense research interest because of their application to high de nition display devices. Recently, polymer stabilized ferroelectric liquid crystals (PSFLCs) have been investigated due to the enhanced electro-optic properties of FLCs. We have utilized thiol-ene photopolymerizations to form a PSFLC system. Thiol-ene photopolymerizations are radical reactions, which proceed via a step growth reaction mechanism. During the polymerization, the polymer network structure is trapped into place due to the rapid transition from low molecular mass monomers and oligomers to high molecular mass polymer. This aspect is evidenced by phase transition data for the FLC, which indicates that the monomer and polymer are not phase separated from the FLC. Infrared dichroism shows that both monomer and polymer are ordered in parallel with the smectic layers of the FLC. Small angle X-ray scattering (SAXS) data show that both monomer and polymer are swelling the smectic layers. Thus, a polymer nanostructure is produced that serves as an ordered, stabilizing host for the FLC.

Electro-optic properties of thiol-ene polymer stabilized ferroelectric liquid crystals

“…In our system, the increase in the tilt angle of the polymer systems over the baseline monomer systems shows that there is an interaction between the polymer and the FLC molecules. Preliminary indications of this polymer ordering effect were shown in previous work [23]. Crosslinking monomer dichroism studies accomplished by Cramer et al showed that the crosslinking monomer segregates in the interlayer spacing of the FLC [23].…”

“…Thiol-enes polymerize via a radical step growth mechanism [23]. A step growth polymerization results in a more homogeneous growth mechanism, where large molecular masses are not formed until high functional group conversion of the monomer.…”

Effect of the polarisation direction and incident angle of a UV light on the electrooptical response of the polymer-stabilised vertically aligned in-plane switching liquid crystal

“…The details of the IR dichroism technique are given in the previous literatures. [18,19] The HDDA molecule has an IR absorption peak at 1635 cm −1 and the IR absorption intensity was examined versus rotation angle of the linear IR polarisers Ψ (Figure 7). Ψ = 0 indicates that the polarisation direction of the incident IR light is parallel to the projected direction of the electric field.…”

Soy-based UV-curable thiol–ene coatings

“…[15][16][17] This feature, in addition to the excellent mechanical and physical properties of the resultant polymers, has attracted extensive research interest in thiol-ene photochemistry and materials in recent years. 16,[18][19][20] UV-curable thiolene materials have been explored as protective coatings, inks, and adhesives. 17,19 Furthermore, the extraordinarily high refractive index of thiol-ene materials enable high value-added applications such as coatings for optical lenses and fibers, and as adhesives for photonic and electronic components.…”

“…17,19 Furthermore, the extraordinarily high refractive index of thiol-ene materials enable high value-added applications such as coatings for optical lenses and fibers, and as adhesives for photonic and electronic components. 18,20,21 It is highly desirable to incorporate bio-renewable materials into the ''green'' UV-curable technologies. Such a combination provides a ''green + green'' solution to the stricter environmental regulations that the coating industry is facing.…”