Molecular Motion-Permeability Relationships in Polycarbonate/Liquid Crystal (Ebba) Composite Membrane

Kajiyama, Tisato; Nagata, Yasuhisa; Maemura, Eiji; Takayanagi, Motowo

doi:10.1246/cl.1979.679

Cited by 51 publications

(17 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subscript i means either LC (liquid crystal) or P (polymer) phase. (4) and (5), we have 1 (6) ECOMP LC P Then, the E, is given by eq.(7). CCOMPCQMP JCOMP (7) where (8) and €, _4LCLC(EPP)+4P(ELC ÷) x L.C.…”

Section: D=ementioning

confidence: 99%

<title>Polymer-LC molecules interaction in the composite system and its electro-optical effects</title>

Kajiyama

Yonekura

Jun-ichiro

et al. 1994

Liquid Crystal Materials, Devices, and Applications III

Self Cite

View full text Add to dashboard Cite

A (polymer/liquid crystal:LC) composite film, in which LC molecules are embedded in a three-dimensional polymer matrix, shows reversible light scattering-light transmission switching upon off-and on-ac. electric fields, respectively. The electro-optical behavior of the composite film was strongly dependent on the LC channel (domain) size in the composite film. The transmittance increased, and also, the rise and decay response times('rR and ID), decreased and increased, respectively, with an increase in the size of LC channel (domain). The electrooptical response of LC molecules is strongly influenced by the miscibility and anchoring strength of LC molecules to the polymeric wall. The miscibility between both phases was evaluated from a distribution of relaxation time for an interfacial polarization. The anchoring effect was also investigated by measuring nonlinearity of the dielectric constant for the composite system.

show abstract

Section: D=ementioning

confidence: 99%

<title>Polymer-LC molecules interaction in the composite system and its electro-optical effects</title>

Kajiyama

Yonekura

Jun-ichiro

et al. 1994

Liquid Crystal Materials, Devices, and Applications III

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, a PDL-free device could be developed by using an absorption effect or a scattering effect of the liquid crystals. A (polymer/liquid crystal) composite film (PLCF) has originally been developed as a gas and liquid permeable material [9]. Then, it was experimentally proven that it shows a good contrast ratio at the visible wavelengths without any polarization configurations [10] and that it functions as a VOA at an optical fiber communication wavelength of about 1.5 μm [11].…”

Section: Introductionmentioning

confidence: 99%

Infrared Extinction of a Dye-Doped (Polymer/Liquid Crystal) Composite Film

et al. 2015

View full text Add to dashboard Cite

Infrared extinction of a dye-doped (polymer/liquid crystal) composite film was investigated. It is found that doping a metal-complex dye into the liquid crystal extended the operation wavelength to an optical fiber communication wavelength of about 1.5 μm. An aperture placed behind the composite film greatly improves an extinction ratio, which suggests the film functions on the basis of light scattering. Some experimental results agree to Rayleigh scattering. The film exhibits the high extinction ratio of 51 or 17.1 dB and a low polarization dependent loss of 7.6% or 0.32 dB and, then, it could be applied to a telecommunication device such as a variable optical attenuator.

show abstract

“…Our primary goals were to demonstrate extensive and reversible changes in permeation for a given membrane system and to characterize permeation properties of low-molar-mass LC materials. To achieve these objectives, photoswitchable LC eutectic mixtures were either dispersed into a host polymer solution and cast as PDLC membranes as described by Kajiyama et al [7], or imbibed directly into the cylindrical "track-etched" micropores of a commercial polycarbonate membrane. Previous studies of nematic LC materials confined in such a micropore environment have shown that the nematic director field configuration is dependent on the interplay of the elastic forces, strength of surface interactions, and the confining volume and shape [8].…”

Section: Introductionmentioning

confidence: 99%

Photoswitchable gas permeation membranes based on azobenzene-doped liquid crystals

2009

View full text Add to dashboard Cite

We have fabricated switchable gas permeation membranes in which a photoswitchable low-molecular-weight liquid crystalline (LC) material acts as the active element. Two different LC eutectic mixtures based on cyanobiphenyls and phenyl benzoates, respectively, were doped with mesogenic azo dyes and infused into commercially available tracketched porous polycarbonate membranes with regular cylindrical pores (0.40 to 10.0 μm). Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photoswitchable membrane to nitrogen. The membrane imbibed with the photoswitchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photogenerated isotropic state demonstrated a 16×-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. The membrane imbibed with the photoswitchable phenyl benzoate LC showed the opposite permeability behavior to the biphenylimbibed membrane, along with nonlinear sorption behavior. Permeability switching response times for the membranes on the order of 5 s were demonstrated using alternating UV and >420-nm radiation at an intensity of 2 mW/cm 2 . The effect of thermomolecular motion on gas sorption and diffusion over the LC-isotropic phase transitions are, for the first time, evaluated under isothermal conditions. These photoswitchable membranes are the first examples of systems that are capable of rapid and reversible gas permeation switching. Such switchable and/or tunable membranes are in high demand for applications in analytics, screening, and membrane reactors.

show abstract

Molecular Motion-Permeability Relationships in Polycarbonate/Liquid Crystal (Ebba) Composite Membrane

Cited by 51 publications

References 5 publications

<title>Polymer-LC molecules interaction in the composite system and its electro-optical effects</title>

<title>Polymer-LC molecules interaction in the composite system and its electro-optical effects</title>

Infrared Extinction of a Dye-Doped (Polymer/Liquid Crystal) Composite Film

Photoswitchable gas permeation membranes based on azobenzene-doped liquid crystals

Contact Info

Product

Resources

About