New side‐chain liquid‐crystalline ionomers. I. Synthesis and characterization of a homopolymer derived from ionic mesogenic groups

Liquid‐crystalline monomer cholesteryl 4‐allyloxybenzoate (M₁), new ionic mesogenic monomer cholesteryl 4‐allyloxy‐3‐(potassium sulfonate)benzoate (M₂), and corresponding polymer P₁ and ionomer P₂ were synthesized. The chemical structures of the monomers and homopolymer were confirmed with Fourier transform infrared and ¹H‐NMR spectroscopy. The mesogenic properties were studied with differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction measurements. The effect of the ionic units on the phase behavior was examined. M₁ showed a cholesteric phase, and M₂ revealed a smectic A phase. P₁ and P₂ displayed smectic A phases. The experimental results demonstrated that the addition of ionic units to the mesogenic molecule not only affected the phase‐transition temperature but also changed the mesogenic phase type. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2511–2516, 2004     

Synthesis and mesomorphic properties of side‐chain cholesteric liquid‐crystalline polymers containing menthyl groups

A series of new cholesteric liquid‐crystalline polysiloxanes ( P₁ – P₅ ) derived from menthyl groups were synthesized. The chemical structures of the monomers and polymers were characterized with Fourier transform infrared, ¹H‐NMR, ¹³C‐NMR, and elemental analyses. The mesomorphic properties and thermal behavior were investigated with differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis, and X‐ray diffraction measurements. The influence of the polymer structure on the thermal behavior was discussed. The monomer diosgeninyl 4‐allyloxybenzoate exhibited a typical cholesteric oily‐streak texture and a focal‐conic texture. Polymers P₁ – P₅ showed thermotropic liquid‐crystalline properties. P₁ displayed a smectic fan‐shaped texture, P₂ – P₅ showed a cholesteric Grandjean texture, and P₆ and P₇ did not show mesomorphic properties. The experimental results demonstrated that the glass‐transition temperature and the clearing temperature decreased, and the mesomorphic properties weakened with an increasing concentration of menthyl units. Moreover, P₁ – P₅ exhibited wide mesophase temperature ranges and high thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5559–5565, 2006     

Synthesis and characterization of side‐chain liquid‐crystalline polyacrylates containing azobenzene moieties

Syntheses of novel liquid‐crystalline polymers containing azobenzene moieties were performed by a convenient route with an acrylate backbone. The azobenzenes were key intermediates of the monomers, and side‐chain liquid‐crystalline polymers were prepared, that is, poly[α‐{4‐[(4‐acetylphenyl)azo]phenoxy}alkyloxy]acrylates, for which the spacer length was 3 or 11 methylene units. In addition, poly[3‐{4‐[(3,5‐dimethylphenyl)azo]phenoxy}propyloxy]acrylate was prepared with a spacer length of 3 methylene units. The structures of the precursors, monomers, and polymers were characterized with Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR techniques. The polymers were obtained by conventional free‐radical polymerization with 2,2′‐azobisisobutyronitrile as an initiator. The phase‐transition temperatures of the polymers were studied with differential scanning calorimetry, and the phase structures were evaluated with a polarizing optical microscopy technique. The results showed that two of the monomers and their corresponding polymers exhibited nematic liquid‐crystalline behavior, and one of the monomers and its corresponding polymer showed smectic liquid‐crystalline behavior. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2653–2661, 2002     

Main‐chain liquid‐crystalline ionomers bearing potassium sulfonate groups

A series of thermotropic main‐chain liquid‐crystalline (LC) ionomers were prepared, which contained potassium sulfonate groups pendent to the chains. The polymers were prepared in an esterifying reaction with potassium ion contents ranging between 0 and 3.9 wt %. The content of potassium ion was characterized by spectrophotometric analysis with sodium tetraphenylboron as the titrant. Chemical structures were determined by various experimental techniques including Fourier transform IR spectroscopy and ¹H‐NMR. LC properties were characterized by differential scanning calorimetry, polarizing optical microscopy, and X‐rays. All of the polymers displayed nematic or smectic mesophases. With increasing potassium sulfonate ionic concentration in the polymers, the melting temperatures and isotropic transition temperatures changed little, whereas the temperature of the smectic A–nematic phase transition increased. The ionic aggregation was tangled with the rigid mesogenic groups of LC segments to form multiple block domains, leading the soft main chains to fold and form a lamellar structure due to their electrostatic interactions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2021–2026, 2005     

Synthesis and mesomorphic properties of side‐chain liquid crystalline ionomers containing sulfonic acid groups

Side‐chain liquid crystalline ionomers containing M₁ (4‐allyoxybenzoyloxy‐4′‐amylbenzoyloxy biphenyl) as mesogenic units and M₂ (4‐undecylenicoxy‐4′‐phenylazobenzene sulfonic acid) as ionic units were synthesized by graft copolymerization. Their liquid crystalline properties were characterized by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The results showed that introduction of nonmesogenic ionic units into polymeric structure could cause additional reduction of the clearing point of the ionomers, compared with the corresponding nonion polymers. When the content of ionic units increased to 8.5%, the ionic clusters and mesogens in the ionomers may be dispersed each other to form multiple blocks, but the introduction of ionic groups in LCIs did not change their mesogenic type. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 304–309, 2007     

Synthesis and characterization of side‐chain cholesteric liquid‐crystalline polysiloxanes containing different space groups

A series of liquid‐crystalline (LC) polysiloxanes were synthesized by two different cholesteric monomers, cholest‐5‐en‐3‐ol(3β)‐10‐undecenoate and cholesteryloxycarbonylmethyl 4‐allyloxybenzoate. The chemical structures and LC properties of the monomers and polymers were characterized by various experimental techniques, including Fourier transform infrared spectroscopy, ¹H‐NMR, elemental analysis, differential scanning calorimetry, and polarized optical microscopy. The specific rotation absolute values increased with increasing rigid spacers between the main chain and the mesogens. All of the polymers exhibited thermotropic LC properties and revealed cholesteric phases with very wide mesophase temperature ranges. With a reduction in the soft‐space groups in the series of polymers, the glass‐transition temperature and the isotropic temperature increased slightly on heating cycles. Reflection spectra of the cholesteric mesophase of the series of polymers showed that the reflected wavelength shifted to short wavelengths with decreasing soft‐space groups in the polymers systems, which suggested that the helical pitch became shorter with increasing rigid‐space groups. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of chiral smectic side‐chain liquid crystalline polysiloxanes and ionomers containing sulfonic acid groups

The synthesis of new chiral smectic A (S_A) side‐chain liquid crystalline polysiloxanes (LCPs) and ionomers (LCIs) containing 4‐allyloxy‐benzoyl‐4‐(S‐2‐ethylhexanoyl) p‐benzenediol bisate (ABB) as mesogenic units and 4‐[[4‐(2‐propenyloxy)phenyl]azo]benzenesulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are confirmed by FTIR spectroscopy or ¹H–NMR. Differential scanning calorimetry (DSC), optical polarizing microscopy, and X‐ray diffraction measurements reveal that all the polymers P_I–P_IV and ionomers P_V–P_VI exhibit S_A texture. The results seem to demonstrate that the tendency toward the S_A‐phase region increases with increasing sulfonic acid concentration, and the thermal stability of the S_A phase is determined by the flexibility of the polymer backbones and the interactions of sulfonic acid groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2335–2340, 2001     

Main‐chain chiral smectic liquid‐crystalline ionomers containing sulfonic acid groups

Three series of main‐chain liquid‐crystalline polymers (P1, P2, and P3) were synthesized by an interfacial condensation reaction of sebacoyl dichloride with various amount of brilliant yellow, isosorbide, and 4,4′‐biphenydiol. P1 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and isosorbide. P2 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol, brilliant yellow, and isosorbide. P3 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and brilliant yellow. P2 and P3 are main‐chain liquid‐crystalline ionomers. P1₂ and P3 series were prepared as model polymers for comparison with the liquid crystalline behavior of ionomers, P2 series. The structures of the polymers were characterized by IR and UV spectroscopy. Differential scanning calorimetry was used to measure the thermal properties of the polymers. The mesogenic properties were investigated by polarized optical microscope, differential scanning calorimetry, and X‐ray diffraction measurements. The results show that P2 series are chiral smectic C (S_mC*) and chiral smectic B (S_mB*) liquid crystalline ionomers exhibiting broken focal‐conic texture and schlieren, as is the polymer P1₂, which has the same amount of 4,4′‐biphenydiol and isosorbide. The introduction of ionic units in P2 series leads to an increase of clearing point, but has not affected the mesogenic type and texture, as compared with the corresponding polymer P1₂. The introduction of chiral units in P2 series leads to a change of mesophase, as compared with P3 series, which exhibit smectic C mesogetic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1254–1263, 2006     

Synthesis and phase behavior of chiral side‐chain liquid‐crystalline polysiloxanes containing two mesogenic groups

The synthesis of chiral side‐chain liquid‐crystalline polysiloxanes containing both cholesteryl undecylenate (M_I) and 4‐allyloxy‐benzoyl‐4‐(S‐2‐ethylhexanoyl) p‐benzenediol bisate (M_II) mesogenic side groups was examined. The chemical structures of the obtained monomers and polymers were confirmed with Fourier transform infrared spectroscopy or ¹H‐NMR techniques. The mesomorphic properties and phase behavior of the synthesized monomers and polymers were investigated with polarizing optical microscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). Copolymers IIP–IVP revealed a smectic‐A phase, and VP and VIP revealed a smectic‐A phase and a cholesteric phase. The experimental results demonstrated that the glass‐transition temperature, the clearing‐point temperature, and the mesomorphic temperature range of IIP–VIP increased with an increase in the concentration of mesogenic M_I units. TGA showed that the temperatures at which 5% mass losses occurred were greater than 300°C for all the polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2670–2676, 2002     

Synthesis and properties of side‐chain liquid‐crystalline polysiloxanes containing hemiphasmidic mesogens

The synthesis of hemiphasmidic monomers 4‐[(3,4,5‐triethoxy)benzoyloxy]‐4′‐[(p‐allyloxy)benzoyloxy]biphenyl (M₁), 4‐[(3,5‐diethoxy)benzoyloxy]‐4′‐[(p‐allyloxy)‐benzoyloxy]biphenyl (M₂), and of the corresponding side‐chain liquid‐crystalline polysiloxanes (P₁, P₂) was carried out. For comparison, rodlike monomer 4‐[(p‐ethoxy)‐benzoyloxy]‐4′‐[(p‐allyloxy)benzoyloxy]biphenyl (M₃) and its polysiloxanes (P₃) were also prepared. The chemical structures of the monomers and polymers obtained were confirmed by FTIR and ¹H‐NMR spectra. Their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The relationship between structures and properties was discussed. It was observed that M₁ and M₃ were enantiotropic nematic phase, M₂ was monotropic mesophase, and their poly(methylsiloxanes) (P₁–P₃) possessed a broad range enantiotropic nematic phases and high thermal stability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 946–952, 2005     

Compatibilization of side‐chain,thermotropic, liquid‐crystalline ionomers to blends of polyamide‐1010 and polypropylene

A novel side‐chain, liquid‐crystalline ionomer (SLCI) with a poly(methyl hydrosiloxane) main chain and side chains containing sulfonic acid groups was used in blends of polyamide‐1010 (PA1010) and polypropylene (PP) as a compatibilizer. The morphological structure, thermal behavior, and liquid‐crystalline properties of the blends were investigated by Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. The morphological structure of the interface of the blends containing SLCI was improved with respect to the blend without SLCI. The compatibilization effect of greater than 8 wt % SLCI for the two phases, PA1010 and PP, was better than the effects of other SLCI contents in the blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2749–2754, 2002; DOI 10.1002/app.10179     

Phase behavior of side‐chain liquid‐crystalline elastomers and their precursors containing para‐nitro azobenzene

Side‐chain liquid‐crystalline copolymethacrylates (PMm's), containing para‐nitro azobenzene as the mesogenic group and 2‐hydroxylethyl methacrylate (HEMA) as a comonomer, were synthesized by radical polymerization, and their corresponding liquid‐crystalline elastomers (LCEm's) were prepared through chemical crosslinking. All of the polymers (PMm's) and the elastomers studied showed enantiotropic smectic A phases; the clearing temperature (T_i) of the PMm polymers decreased with increasing amount of HEMA, and the T_i of the corresponding LCEm's decreased compared to that of their precursors. Small‐angle X‐ray scattering studies on the copolymers quenched from their liquid‐crystalline phases indicated that the characteristic distance increased with increasing amorphous component content and thus, the amorphous components were in between the smectic layers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2275–2279, 2003     

Synthesis and characterization of chiral side‐chain liquid‐crystalline polymer containing menthol ester

The synthesis of new chiral side‐chain liquid‐crystalline polysiloxanes containing p‐(allyoxy)benzoxy‐p‐chlorophenyl (ABCH) as mesogenic units and undecylenic acid menthol ester (UM) as chiral nonmesogenic units is presented. The chemical structures of monomers and polymers are confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to measure thermal properties of those polymers. Mesogenic properties are characterized by polarized optical microscope (POM), DSC, and small‐angle X‐ray diffraction. Analytic results revealed that polymers P₀–P₆ are thermotropic liquid‐crystalline polymers with low glass transition; Polymers P₂–P₆ exhibit chiral smectic liquid‐crystalline properties with marble texture, optical rotation, and a sharp reflection at low angles in X‐ray diffraction; polymers P₀, P₁ only exhibit smectic liquid‐crystalline properties without chirality; and P₇ only exhibits chirality without liquid‐crystalline properties. All the polymers exhibit good thermal stability with temperature of 5% mass loss over 297°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2845–2851, 2003     

Synthesis and properties of side chain cholesteric liquid‐crystalline polyacrylates containing two mesogenic groups

The synthesis of side chain cholesteric liquid‐crystalline polymers containing both 4‐cholesteryl‐4'‐acryloyloxybenzoate (M_I) and 4‐methoxyphenyl‐4'‐acryloyloxybenzoate (M_II) mesogenic side groups is described. The chemical structures of the obtained monomers and polymers are confirmed by Fourier transform infrared (FTIR) spectroscopy. The phase behavior and optical properties of the synthesized monomers and polymers were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetric analyses (TGA). The homopolymer IP reveals a cholesteric phase and VIIP displays a nematic phase. The copolymers IIP–VIP exhibit, respectively, cholesteric oily‐streak texture and focal‐conic texture. The fixation of the helical pitch and oily‐streak texture of the cholesteric phase is achieved by quenching, and polymer films with different reflection colors are obtained. The experimental results demonstrate that the glass transition temperature (T_g) and the melting temperature (T_m) of the copolymers IIP–VIP decrease, whereas the isotropization temperature (T_i) and the mesomorphic temperature range (ΔT) increase with increasing content of mesogenic M_II units. TGA results indicate that the temperatures at which 5% mass loss occurred (T_5wt%) of all copolymers are >245°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1936–1941, 2003     

Synthesis and characterization of side‐chain cholesteric liquid‐crystalline polymers derived from steroid substituents

A series of new cholesteric liquid‐crystalline polysiloxanes derived from steroid substituents were synthesized. The chemical structures of the monomers or polymers obtained were characterized by FTIR, element analyses, ¹H NMR, and ¹³C NMR. Their mesogenic properties and thermal stability were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction measurements. Monomers exhibited typical cholesteric focal‐conic or spiral texture. The polymers P ₁? P ₆ showed cholesteric phase and P ₇ displayed smectic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

聚硅氧烷季铵盐的合成及其抗菌性

以六甲基二硅氧烷(MM)为封头剂，氢氧化四甲铵的硅醇盐为催化剂，使N，N-二乙基-氨丙基甲基二甲氧基硅烷通过水解再和八甲基环四硅氧烷(D4)制得叔胺基硅油，再以氯化苄为季铵化试剂．合成了聚硅氧烷季铵盐。应用IR和^1NMR对产品结构进行了表征，结果与预期值基本吻合。该产品具有明显的表面活性剂性能，测得其临界胶束浓度cmc为0．05％，最小表面张力σcmc为44．8mN／m。抑菌圈实验表明：产品对大肠杆菌有优良的抗菌性，对霉菌有一定的抑制作用。AATCC100抗菌实验表明：质量分数大于0．5％的聚硅氧烷季铵盐水溶液对大肠杆菌的抑菌率达到了100％。     

Synthesis,structures, and properties of side‐chain cholesteric liquid‐crystalline polysiloxanes

The synthesis of three cholesteric monomers and side‐chain liquid‐crystalline polymers was described. The structure–property relationships of monomers IM–IIIM and polymers IP–IIIP were discussed. Their phase behavior and optical properties were investigated by differential scanning calorimetry, thermogravimetric analyses (TGA), and polarizing optical microscopy. Monomers IM–IIIM exhibited cholesteric oily‐streak texture and focal‐conic texture. Polymers IIP and IIIP revealed smectic A fan‐shaped texture and cholesteric grandjean texture, respectively. Experimental results demonstrated that the selective reflection of IM–IIIM shifted to the short‐wavelength region with increasing the flexible spacer length or decreasing the rigidity of the mesogen. Polymers with a longer flexible spacer had lower glass‐transition temperatures and wider mesomorphic temperature ranges. TGA showed that the temperatures at which 5% weight loss occurred were greater than 300°C for all the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3944–3950, 2003     

Mesomomorphism enhancement of modified side‐chain liquid‐crystalline polysiloxanes by copolymerization

The liquid‐crystalline (LC) monomer 4‐allyoxybenzoyloxy‐4′‐buthylbenzoyloxy‐p‐phenyl (M₁), whose LC phase appeared at lower temperatures, from 137 to 227°C, and the modified mesogenic monomer 4‐allyoxybenzoyloxy‐4′‐methyloxybenzoyloxy‐p‐biphenyl (M₂), whose LC phase appeared at higher temperatures, from 185 to 312°C, were prepared. A series of side‐chain LC polysiloxanes containing M₁ and M₂ were prepared by graft copolymerization. Their LC properties were characterized by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction. The results show that the introduction of the modified mesogenic monomer M₂ into the polymeric structure caused an additional increase in the clearing point (isotropic transition temperature) of the corresponding polysiloxanes, compared with unmodified polysiloxanes, but did not significantly affect the glass‐transition temperature. Moreover, the modified polysiloxanes exhibited nematic phases as the unmodified polymer did. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1196–1201, 2005     

Ion aggregation in the polysiloxane ionomers bearing pendant quaternary ammonium groups

Polysiloxane ionomers bearing pendant quaternary ammonium groups were synthesized through the Menshutkin reaction of poly(γ‐chloropropylmethylsiloxane‐co‐dimethylsiloxane) with N,N‐dimethylbenzylamine. Ion aggregation in the ionomers with different contents of the quaternary ammonium groups was investigated by torsion braid analysis, transmission electron microscopy, and rheological measurements. It was found that the incorporation of the quaternary ammonium groups did not make a significant effect on the glass transition temperature of the polysiloxane matrix. The glass transition of the cluster phase was found in the range of ?20–40°C, depending on the concentration of the ion pair. The cluster phase was visualized under TEM when the concentration of the quaternary ammonium group exceeded a critical value. It was indicated by rheological data that the movement of polymer chains in the cluster phase of the polysiloxane ionomers was not restricted at the room temperature, which might be related to the weaker interaction between the bulky quaternary ammonium ion pairs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3099–3104, 2002; DOI 10.1002/app.10009     

Synthesis and characterization of liquid crystalline ionomers with polymethylhydrosiloxane main-chain- and side-chain-containing sulfonic acid groups

A novel thermotropic side-chain liquid crystalline ionomer (LCI) containing sulfonic acid groups on the side-chain was synthesized by graft copolymerization of mesogenic monomer 4-allyloxy-benzoxy-4′-methoxyphenyl (ABM) and nonemesogenic monomer 4-allyloxy-azobenzene sulfonic acid (AABS) upon polymethylhydrosiloxane (PMHS). The chemical structures of the polymers were confirmed by IR spectroscopy. DSC and TGA were used to measure the thermal properties of those polymers and the mesogenic properties were characterized by polarized optical micrography (POM), DSC, and WAXD. The clearing point temperature (T_c) of these liquid crystalline ionomers was enhanced 50–60°C compared with the polymer without ionic groups. The LCIs exhibit a broad smectic mesogenic region of 80–90°C; the thermal stability below 200°C of the polymers decreases with increasing sulfonic acid concentration. The inherent viscosity of 0.5% solutions decreased with increasing sulfonic acid concentration in the polymer chains. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1555–1561, 1998