Dissolving and Aligning Carbon Nanotubes in Thermotropic Liquid Crystals

It has been widely recognized that the combination of carbon nanotubes (CNTs) and low molar mass thermotropic liquid crystals (tLCs) not only provides a useful way to align CNTs, but also dramatically enhances the tLC performance especially in the liquid crystal display technology. Such CNT-tLC nanocomposites have ignited hopes to address many stubborn problems within the field, such as low contrast, slow response, and narrow view angle. However, this material development has been limited by the poor solubility of CNTs in tLCs. Here, we describe an effective strategy to solve the problem. Prior to integrating with tLCs, pristine CNTs are physically “coated” by a liquid crystalline polymer (LCP) which is compatible with tLCs. The homogeneous CNT-tLC composite obtained in this way is stable for over 6 months, and the concentration of CNTs in tLCs can reach 1 wt %. We further demonstrate the alignment of CNTs at high CNT concentrations by an electric field with a theory to model the impedance response of the CNT-tLC mixture

Making and Remaking Dynamic 3D Structures by Shining Light on Flat Liquid Crystalline Vitrimer Films without a Mold

Making dynamic three-dimensional (3D) structures capable of reversible shape changes or locomotion purely out of dry polymers is very difficult. Meanwhile, no previous dynamic 3D structures can be remade into new configurations while being resilient to mechanical damages and low temperature. Here, we show that light-activated transesterification in carbon nanotube dispersed liquid crystalline vitrimers enables flexible design and easy building of dynamic 3D structures out of flat films upon irradiation of light without screws, glues, or molds. Shining light also enables dynamic 3D structures to be quickly modified on demand, restored from distortion, repaired if broken, in situ healed when microcrack appears, assembled for more sophisticated structures, reconfigured, and recycled after use. Furthermore, the fabrication, reconfiguration, actuation, reparation, and assembly as well as healing can be performed even at extremely low temperatures (e.g., −130 °C)

Organogels and Liquid Crystalline Properties of Amino Acid-Based Dendrons: A Systematic Study on Structure–Property Relationship

Self-assembly behaviors of a series of amino acids-based dendrons, from the first generation (G1) to the third generation (G3) with various focal moieties or peripheral groups, were systematically studied. The supramolecular structures in organogels, thermotropic and lyotropic liquid crystals (LCs) were measured. The influence of the focal groups, dendritic branches, and generation numbers on the mesophase of organogels or LCs was studied by a combination of experimental techniques including transmission electronic spectrometry (TEM), atomic force microscopy (AFM), infrared (IR) spectra, wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). It was found that the gelation ability of the dendrons in organic solvents was highly related to the generation; namely, none of the G1 dendrons could form organogels, G2 dendrons displayed good gelation ability, and G3 dendrons gelled the organic solvents with the lowest critical gelation concentration. Oscillatory shear measurements indicated that the gels behaved as viscoelastic materials with good tolerance to external shear force. In addition, all of G3 dendrons and some G2 dendrons were capable of self-organizing to afford the thermotropic and lyotropic LCs

Stable Electrochromic Polyschiff Bases Containing Triarylamine Units: Synthesis, Electrochemical, and Acidochromic Properties

<p>Four polySchiff bases containing different triphenylamine moieties were synthesized based on the polycondensation reaction of 4-methyl-4′,4″-diformyltriphenylamine with various aromatic diamines which contain triphenylamine groups. Especially, 4-methyl-4′,4″-diformyltriphenylamine was obtained by the reduction of compound with nitril groups with diisiobutylaluminum hydride. The structures of 4-methyl-4′,4″-diformyltriphenylamine and polySchiff bases were confirmed by Fourier transform infrared and the nuclear magnetic resonance techniques. The polySchiff bases displayed good thermal stability, with 5% weight loss above 450°C under nitrogen atmosphere. All the polymer films exhibited good electrochemical and electrochromic stability under repeatedly switching electrode voltages. Take the polySchiff base-d, for example, the color changed from the pale yellow neutral state to green and crimson oxidized state at applied potentials ranging from 0.0 to 1.6 V. The polySchiff bases showed obvious acidochromic properties. The polySchiff bases exhibited a typical photovoltaic response and good stability. Consequently, the polySchiff bases would be promising electrochromic and acidochromic materials.</p

The associations of total homocysteine (quartiles) with PWMHs and DWMHs.

<p>The associations of total homocysteine (quartiles) with PWMHs and DWMHs.</p

The associations of total homocysteine (quartiles) with the frontal WMHs.

<p>The associations of total homocysteine (quartiles) with the frontal WMHs.</p

Demographic and clinical characteristics.

<p>Demographic and clinical characteristics.</p

The associations of total homocysteine (quartiles) with WMH severity.

<p>The associations of total homocysteine (quartiles) with WMH severity.</p

Distribution of percentage of tumor cells with <i>MET</i> gene copy number ≥3 among different MET IHC scores in PRCC (N = 88) patients.

<p>Distribution of percentage of tumor cells with <i>MET</i> gene copy number ≥3 among different MET IHC scores in PRCC (N = 88) patients.</p

Correlation between percentage of tumor cells with <i>MET</i> gene copy number ≥3 and percentage of tumor cells with CEP7 gene copy number ≥3 in PRCC (N = 91) patients.

<p>Correlation between percentage of tumor cells with <i>MET</i> gene copy number ≥3 and percentage of tumor cells with CEP7 gene copy number ≥3 in PRCC (N = 91) patients.</p