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Two monomers o -( m -triphenyl)-terephthaloyl chloride (TPH1-COCl) and m -( m -triphenyl)- isophthaloyl chloride (TPH2-COCl) with bulky pendant groups were prepared, and they were polymerized with p -phenylenediamine (PPD) or copolymerized with PPD and terephthaloyl chloride (TPC) to prepare aromatic polyamides which were named TPH1 polymer and TPH2 polymer, respectively. The structures of the monomers with bulky pendant groups and the polymers were characterized by 1 H NMR and gel permeation chromatography. The resulting polymers are soluble in some organic solvents such as N -methyl-2-pyrrolidone. However, the solubility of the two series of polymers was different due to the different structures of the two monomers, and it is affected by the feeding ratio of the monomers. Both kinds of polymers have good thermal stabilities with 5% weight loss temperatures close to 500 °C. And glass transitions of some TPH2 polymers were observed. Most of these polyamides show lyotropic liquid crystalline (LLC) behaviors as evidenced by polarized light microscopy results. And the LLC properties are influenced by the structures, molecular weights, and concentrations of the polymers.

With a pyridine derivative containing a calamitic mesogen 4-((6-((4'-((4-hexylphenyl)ethynyl)-[1,1′-biphenyl]-4-yl)oxy)hexyl)oxy)pyridine (HEBC6) used as the hydrogen-bonding acceptor and polydimethylsiloxane-b-poly(2,5-bis(4-carboxy phenyl)styrene) (PDMS-b-PM3H) as the hydrogen-bonding donor, a series of supramolecular liquid crystalline block copolymers (SLCBCPs) were prepared through hydrogen bonding. In the supramolecular block, the calamitic mesogen was decoupled from the motion of PM3H chains by using a flexible spacer. Different microphase-separated nanostructures and liquid crystalline (LC) structures were obtained by varying the degree of polymerization of the PM3H block and the molar ratio of HEBC6 to PDMS-b-PM3H. The SLCBCPs can self-assemble into hexagonally packed cylinders (HEX), lamellae (LAM), and inverted HEX. Smectic A phase and parallel packing of the calamitic mesogens were also observed on a smaller length scale, and these two ordered structures are synergistic and promotional. Therefore, hierarchically ordered structures can be obtained from these SLCBCPs.

Mesogen-jacketed liquid crystalline polymer (MJLCP) is a typical rod-shaped macromolecule. Its unique molecular architecture allows one to tune the geometric parameters of the macromolecular rod. Moreover, the rod surface chemistry can be controlled by designing the peripheral groups of the lateral mesogens. In previous work in this system, short alkyl chains have been used and the resultant macromolecular rods therefore have a hydrophobic surface. In this paper, we report using oligo(oxyethylene) groups as the peripheral groups of the lateral mesogens. Poly{{2,5-bis[4-methoxyoligo(oxyethylene)phenyl]oxycarbonyl}styene} (PnEOPCS) with different oligo(oxyethylene) chain length has been synthesized. These oligo(oxyethylene) groups led to macromolecular rods with hydrophilic surface. Differential scanning calorimetry, polarized light microscopy, and one-/two-dimensional wide-angle X-ray diffraction experiments were carried out to study the phase structures and phase behaviors of this series of polymer. The existence of flexible polar groups lowered the glass transition temperatures of PnEOPCS. All polymers studied showed supramolecular columnar nematic or hexatic columnar nematic phase, which arose from the parallel alignment of the polymer supramolecular rods. The diameter of the cylindrical building block increased with increasing the length of the oligo(oxyethylene) groups. The macromolecular rod surface can be further tuned by complexation the oligo(oxyethylene) with lithium salts. Detailed study showed that this complexation also tremendously affected the liquid crystalline phase of the polymer.

Three novel allyl–maleimide monomers (i.e., A 2 B, AB and AB 2 ) were designed, synthesized and thermally cured to yield a series of high-performance allyl–maleimide resins. All the monomers obtained are readily soluble in common organic solvents enabling an easy solution processing. The thermal properties of the three monomers were studied by the differential scanning calorimetry (DSC). A 2 B and AB showed fairly low melting temperature ( T m 2 B, PAB and PAB 2 ) was studied by the thermogravimetric analysis (TGA). Dynamic mechanical analysis (DMA) was used to investigate the dynamic mechanical properties of the composites based on the cured allyl–maleimide resins. PA 2 B and PAB 2 showed good glass transition temperatures ( T g > 270 °C) and their corresponding composites showed high bending modulus ( E ′ > 1900 MPa). Allyl-compound-modified BMI resins based on AB monomer were prepared. Rheometer revealed that the processability of the prepolymer (BR–AB-pre) was improved by the addition of AB monomer. The cured BMI resins (BR and BR–AB) showed good thermal stability ( T d > 400 °C, both in nitrogen and in the air), high glass transition temperature ( T g > 320 °C), and good mechanical properties and low water uptake (

A mesogen-jacketed polymer P-Ct {poly{2,5-bis[(5-tert-butylphenyl)-1,3,4-oxadiazole]styrene}} has been investigated as a host material for IrMDPP [Ir(III)bis(5-methyl-2,3-diphenylpyrazine) (acetyl acetonate)] doped polymer electrophosphorescent device. It was found that the device with P-Ct was more efficient than that with PVK. The maximum luminance and external luminous efficiency can reach 3702 cd/m2 and 0.83 cd/A, respectively, which were higher than those of device with PVK (1999 cd/m2 and 0.68 cd/A), which can be partly explained by the more balanced carrier injection and transportation and longer lifetime of excitons in P-Ct–TPD–IrMDPP. It was also found that as the IrMDPP content increased in P-Ct–TPD, the EL spectra color shifts from green-yellow to yellow-orange and were different from PL spectra, which was partly due to the dominating role of direct charge-trapping and recombination in the EL process over the energy-transfer routes.

A series of novel mesogen-jacketed polymers, poly{2,5-bis[(5-tert-butylphenyl)-1,3,4-oxadiazole]styrene} (P-Ct) and poly{2,5-bis[(5-alkoxyl-phenyl)-1,3,4-oxadiazole]styrene} (P-OCn, n is the number of carbons in the alkoxyl groups, n = 6, 8, 10, 12, 14), were incorporated into polymer light-emitting device as the light-emitting layers. All of the polymers had excellent solubility in common organic solvents. The UV and PL spectra for P-Ct were 312 and 400 nm while for P-OCn they were around 328 and 420 nm in the film. There was no red shift in the PL spectrum of P-Ct after heat treatment which maybe related to the jacketed structure. All of the polymers showed high PL quantum yields in THF solution. From the cyclic voltammetry measurement at room temperature, HOMO levels of the polymers were varied from −5.66 to −6.12 eV, LUMO levels were varied from −2.45 to −2.81 eV. Furthermore, the influence of the alkoxyl lengths in four different device configurations was compared. For the device configuration c: ITO/PVK/P-OC8/Ca/Ag, the maximum luminance and maximum external quantum efficiency were obtained for P-OC8 which maybe related to the easier electron injection and transport. Efficiency of P-OC8 was not improved with device d which proved the electron transporting characteristics of P-OC8.

Two novel bismaleimide (BMI) monomers containing 1,3,4-oxadiazole, i.e., 5- tert -butyl-1,3-di[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]benzene (Buoxd) and 4,4′-[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]diphenyldimethylsilane (Sioxd), were designed, synthesized and copolymerized with 4,4′-bismaleimidodiphenylmethane (BMDM) to yield a new series of high-performance bismaleimide resins. Both monomers obtained are readily soluble in common organic solvents, such as dichloromethane and chloroform, enabling an easy solution processing. The thermal properties of the two monomers were carefully studied by the differential scanning calorimetry (DSC), optical microscopy and thermogravimetric analysis (TGA, simultaneous DSC). The BMI resins based on a mixture of Buoxd (or Sioxd) and BMDM in a weight ratio of 10% were prepared. DSC investigations showed that the thermal curing of the BMI resins could be accomplished at a lower temperature than the thermal curing temperatures of Buoxd and Sioxd, and the thermal processing window, i.e., the temperature range between the melting transition and thermal curing process, was over 26 °C. The thermal properties and thermal mechanical properties of the resulting BMI resins were investigated by DSC, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). No glass transition temperature was found in the range of 50–350 °C, and very good thermal stability ( T d > 490 °C in nitrogen) and high thermo-oxidative stability ( T d > 460 °C in air) were revealed. Composites composed of the above BMI resins and glass cloth were also prepared, which showed high bending modulus (>1.6 GPa) at a very high temperature (e.g., 400 °C).

Diblock copolymers comprising crystallizable poly(e-caprolactone) and poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS) were synthesized by ring-opening polymerization of e-caprolactone and subsequent atom transfer radical polymerization (ATRP) of MPCS. The molecular structure of the copolymers was confirmed by 1H NMR spectroscopy and GPC. Kinetic study of ATRP showed that the polymerization proceeded in a controlled way up to high conversions. Three series of diblock copolymers were obtained with relatively narrow polydispersity indices (PDI≤1.11) and PCL blocks of 8000, 12,900, and 22,800 molecular weights, respectively. The existence of microphase separation was identified by differential scanning calorimetry (DSC) and directly observed through transmission electron microscopy (TEM). The melting behavior of PCL block was significantly affected by the length of PCL block and composition of PMPCS. The thermotropic liquid crystalline behavior was examined by polarized optical microscopy (POM) and DSC. The result showed that the diblock copolymer exhibited liquid crystalline behavior when the degree of polymerization (DP) of PMPCS block was not less than 44.