Directing Polymorphism in the Helical Nanofilament Phase

Herein, it is reported that the polymorphism in the helical nanofilament (HNF, B-4) liquid-crystalline phase depends on the fabrication methods, that is, UV-driven formation and template-assisted self-assembly in the nanoconfined geometry. As a result, uniaxially oriented HNFs with different helical structures were obtained, in which generation of the twisted-ribbon and cylindrical-ribbon polymorphs showed that even the molecular lattice has a different orientation. The detailed structures were directly observed by SEM and grazing-incidence X-ray diffraction with synchrotron radiation. The resultant polymorphs could be used in chiro-optical applications due to the capability for fine control of the helical structures

Security use of the chiral photonic film made of helical liquid crystal structures

The color change of photonic crystals (PCs) has been widely studied due to their beauty and anti-counterfeiting applications. Herein, we demonstrated security codes based on chiral PCs that cannot be easily mimicked and are quite different from the conventional technology used currently. The chiral PCs can be made by self-assembly and the structural colors change based on the polarization of the light in the transmission mode. These color changes are easily detected in real-time and are useful in the fabrication of anti-counterfeiting patterns that show beautiful and diverse color changes with rotating polarizers. We believe this can provide a new platform in various security and color-based applications11Nsciescopu

One-pot synthesis of biofoams from castor oil and cellulose microfibers for energy absorption impact materials

The use of renewable feedstocks in foam technology has created a worldwide demand for more sustainable materials. Castor oil is a vegetable oil, composed mainly of triricinoglycerol, a natural polyol, suitable for polyurethane foam production. In this study, castor oil and variable amounts of microcrystalline cellulose (MCC) fibers were used in a straightforward one-pot synthesis approach for the preparation of novel biofoams. The ensuing biofoams were characterized by several techniques, including attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis, and their mechanical performance was evaluated by compression mechanical testing and by dynamic mechanical thermal analysis. They were (semi-) flexible, with a cell-like morphology and reinforced toughness due to the use of MCC. They had a Young's modulus varying between 0.188 and 1.06 MPa depending on the amount of MCC used and were thermally stable up to 267 A degrees C. The properties of these novel biofoams enable them to be strong candidates for use as tough, energy-absorbing foams, advantageously prepared using renewable-based resources