<link rel="stylesheet" href="styles.cf390c6bfbe7555f.css">

Browsing by Author "HSIUE, GH"

Now showing 1 - 10 of 10
  • Thumbnail Image
    Item type:Item,
    GAS PERMEATION THROUGH A SIDE-CHAIN LIQUID-CRYSTALLINE POLYSILOXANE-BASED MEMBRANE
    (1991-09-01)
    CHEN, DS
    ;
    HSIUE, GH
    ;
    HSU, CS
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    A membrane was prepared by sandwiching the side-chain liquid-crystalline polysiloxane (LCP) 3 between two porous poly(propylene) (Celgard) films. Permeation properties for H-2, O2, N2, CH4 and CO2 through the side-chain LCP-based membrane was measured using a gas-chromatographic method at several different temperatures corresponding to the different states of of the side-chain LCP. The gas permeation behaviour depends strongly on the different states of the side-chain LCP. The plots of permeability versus reciprocal temperature show an abrupt change of the slope in the vicinity of the glass transition temperature (T(g)) of the side-chain LCP for all five gases. The activation energy for permeation obtained at these different states exhibits different values. The value obtained in the liquid-crystalline state is the highest. Separation factors (P(O2)/P(N2)) and (P(CO2)/P(CH4)) exhibit an unusual behaviour when the temperature changes across T(g). They increase abruptly when the temperature increases and the phase changes from the glassy state to the liquid-crystalline state of the side-chain LCP. The fact that both permeability and selectivity increases with increasing temperature above the glass transition is attributed to the supermolecular arrangement of the liquid-crystalline state of the side-chain LCP.
  • Thumbnail Image
    Item type:Item,
  • Thumbnail Image
    Item type:Item,
  • Thumbnail Image
    Item type:Item,
    LIQUID-CRYSTALLINE POLYMERS CONTAINING MACROCYCLIC POLYETHERS .2. SIDE-CHAIN LIQUID-CRYSTALLINE COPOLYSILOXANES CONTAINING MESOGENIC UNITS BASED ON 1,3-DIOXANE-2,5-DIYL AND BENZO[15]-CROWN-5
    (1991-10-01)
    HSIUE, GH
    ;
    WEN, JS
    ;
    HSU, CS
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    Synthesis and characterization of a series of copolysiloxanes containing crown ether and trans-1,3-dioxane based mesogens are presented. The phase behaviour of the copolymers was studied using differential scanning calorimetry and optical polarizing microscopy and compared with the phase behaviour of the corresponding copolysiloxane-containing crown ether and biphenyl-based mesogens. Two copolysiloxanes containing trans-2-(benzo-[15]crown-5)-5-(omega-alkan-1-yloxy)-1,3-dioxane side groups present no liquid-crystalline behaviour. The other four copolysiloxanes exhibit a nematic mesophase and undergo side-chain crystallization at low temperature. Two of the four copolysiloxanes which contain a trans-1,3-dioxane-2,5-diyl group in the mesogenic unit present lower isotropization temperatures and narrower mesophase ranges than the other two. This result reveals that replacing a phenyl ring in the mesogenic unit of a liquid-crystalline polymer by a trans-1,3-dioxane ring will decrease the thermal stability of the mesophase exhibited by this polymer.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS AND CHARACTERIZATION OF FERROELECTRIC LIQUID-CRYSTALLINE POLYSILOXANES AND POLYMETHACRYLATES CONTAINING [(S)-2-METHYL-1-BUTOXY]PHENYL 4-(ALKYLOXY)BIPHENYL-4'-CARBOXYLATE SIDE GROUPS
    (1992-12-21)
    HSU, CS
    ;
    LIN, JH
    ;
    CHOU, LR
    ;
    HSIUE, GH
    ;
    應用化學系
    The synthesis of side-chain liquid crystalline polysiloxanes and polymethacrylates containing 4- [(S)-2-methyl-1-butoxy]phenyl 4-hydroxybiphenyl-4'-carboxylate moieties as mesogenic units and aliphatic spacers containing respectively three to eleven methylene units is presented. Differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction measurements reveal chiral smectic mesomorphism for all polymers. Both polysiloxanes which contain respectively six and eleven methylene units in the spacers exhibit smectic A, chiral smectic C, and smectic B phases. Among the polymethacrylates prepared in this study, the polymethacrylate containing eleven methylene units in its spacers is the only one revealing smectic A and chiral smectic C phases. The results seem to demonstrate that the tendency toward chiral smectic C mesomorphism increases with increasing spacer length, and the thermal stability of the chiral smectic C mesophase is determined by the flexibility of the polymer backbone.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTALLINE COPOLYSILOXANES CONTAINING AZOBENZENE DYES AND 1,3-DIOXANE BASED MESOGENIC SIDE GROUPS
    (1993-02-01)
    HSIUE, GH
    ;
    WEN, JS
    ;
    HSU, CS
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    The synthesis and characterization of nine side-chain liquid crystalline copolysiloxanes containing trans-5-(n-undecanyl)-2-(4-cyanophenyl)-1,3-dioxane and 4-(alkanyloxyphenylazo)benzonitrile side groups are presented. The azobenzene dye contents in the copolymers range from about 5 to 20 wt.-%. The nature of the mesophase exhibited by the copolysiloxanes depends very much on the dye concentration. Three copolysiloxanes which contain about 5 wt.-% azobenzene dye, display a smectic A phase while the other six copolysiloxanes which contain more then 10 wt.-% azobenzene dye, exhibit a nematic phase. All the obtained copolysiloxanes show a very low glass transition temperature and a very wide temperature range of mesophase.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS AND ELECTROOPTICAL PROPERTIES OF SOME FERROELECTRIC LIQUID-CRYSTALLINE POLYMERS
    (1995-07-01)
    HSU, CS
    ;
    SHIH, LJ
    ;
    HSIUE, GH
    ;
    交大名義發表
    ;
    應用化學系
    The synthesis and characterization of several series of ferroelectric side chain polymers were presented. Differential scanning calorimetry, optical polarizing microscopy and X-ray diffraction measurement were used to determine their thermal transitions and analyze their anisotropic textures. The influence of polymer backbones, flexible spacers, mesogenic cores as well as chiral end groups on the mesomorphic properties of the polymers was discussed. Furthermore, the dielectric relaxation properties of the obtained polymers were also evaluated.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS AND THERMAL-BEHAVIOR OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMETHACRYLATES CONTAINING TOLANE-BASED MESOGENIC SIDE-GROUPS
    (1994-04-30)
    HSIEH, CJ
    ;
    WU, SH
    ;
    HSIUE, GH
    ;
    HSU, CS
    ;
    應用化學系
    The synthesis and characterization of nine polymethacrylates containing 4-alkoxy-4'-tri-fluoromethyltolane, 4-alkoxy-4'-cyanotolane, and 4-alkoxy-4'-nitrotolane side groups were described in this study. The phase behavior of the prepared monomers and polymers was characterized by differential scanning calorimetry, optical polarizing microscopy, and x-ray diffraction. All of the obtained monomers exhibit no mesophase, while most of the synthesized polymers reveal enantiotropic mesomorphism. The polymethacrylate containing 4-propanyloxy-4'-nitrotolane side groups was the only one which shows no mesomorphic behavior. Both the spacer length and the nature of terminal groups have profound influence on the phase transition temperatures and thermal stability of the mesophase. The polymers with longer spacers tend to form a more ordered mesophase with a wider temperature range. Among three polymers with the same spacer length, the polymer with a trifluoromethyl terminal end group is inclined to form a more ordered mesophase than the other two polymers. No side chain crystallization occurred for all obtained polymers. (C) 1994 John Wiley & Sons, Inc.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS AND X-RAY-DIFFRACTION OF FERROELECTRIC LIQUID-CRYSTALLINE POLYSILOXANES CONTAINING 4'-(2-CHLORO-3-METHYL-PENTANOYLOXY)-4-ALKANYLOXYBIPHENYL SIDE-GROUPS
    (1994-07-01)
    HSIUE, GH
    ;
    HSIEH, PJ
    ;
    WU, SL
    ;
    HSU, CS
    ;
    應用化學系
    The synthesis and characterization of side-chain liquid crystalline polysiloxanes containing (2S,3S)-4'-(2-chloro-3-methylpentanoyloxy)-4-alkanyloxybiphenyl side groups are presented. All the obtained polymers exhibit smectic mesomorphism. Those polymers containing a spacer length longer than 8 methylene units reveal respectively enantiotropic S(A), S(C)* and S(B) phases. The result demonstrates that the tendency toward the S(C)* phase increases with increasing the spacer length.
  • Thumbnail Image
    Item type:Item,
    SYNTHESIS OF LIQUID-CRYSTALLINE POLYSILOXANES AND POLYMETHACRYLATES WITH BROAD TEMPERATURE RANGES OF THE CHIRAL SMECTIC-C PHASE
    (1993-06-07)
    HSU, CS
    ;
    SHIH, LJ
    ;
    HSIUE, GH
    ;
    應用化學系
    ;
    Department of Applied Chemistry
    The synthesis of side-chain liquid crystalline polysiloxanes and polymethacrylates containing oligooxyethylene spacers and 4-(S)-2-methyl-1-butyl [[(4-hydroxybiphenyl-4'-yl)carbony;]oxy]benzoate mesogenic side groups is presented. Differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction measurements reveal chiral smectic mesomorphism for all polymers. All three polysiloxanes present enantiotropic smectic A and chiral smectic C phases. The chiral smectic C phase covers a very broad temperature range (about 200-degrees-C). Among polymethacrylates prepared in this study, the polymethacrylate which contains three oxyethylene units in its spacer is the only one revealing smectic A and chiral smectic C phases. The results seem to demonstrate that the tendency toward a chiral smectic C phase increases with increasing the flexibility of the polymer backbone and the oligooxyethylene spacer can increase dramatically the thermal stability of the chiral smectic C phase.