The mechanical defensive performance of fruit cuticular membranes (CMs) is largely dependent on the molecular arrangement of their constituents. Here, we elucidated nano-sized interactions between cutin and triterpenoids in the cuticular matrix of Fuyu persimmon fruits ( Diospyros kaki Thunb. cv. Fuyu), focusing on the mechanical properties using a combination of polymer analyses. The fruit CMs of Fuyu were primarily composed of wax (34.7%), which was predominantly triterpenoids followed by higher aliphatic compounds, and cutin (48.4%), primarily consisting of 9,10-epoxy-18-hydroxyoctadecanoic acid and 9,10,18-trihydroxyoctadecanoic acid. Based on the tensile tests of the CM, the removal of wax lead to a considerable decrease in the maximum stress and elastic modulus accompanied by an increase in the maximum strain, indicating that wax is of significant importance for maintaining the mechanical strength of the CM. Wide-angle X-ray diffraction and relaxation time measurements using solid-state 13C nuclear magnetic resonance indicated that the triterpenoids in the cuticular matrix construct a nanocomposite at a mixing scale below 20-24 nm; however, the higher aliphatic compounds did not exhibit clear interactions with cutin. The results indicated that the triterpenoids in the cuticular matrix endow toughness to the CM by functioning as a nanofiller.

This article surveys progress in both fundamental and applied research related to cellulosic liquid crystals, mainly of chiral nematic order. These liquid crystals are divided into two different classes, namely cellulosic macromolecules and cellulose nanocrystals (CNCs), depending on the mesogenic constituent. We start with a review of the fundamental and chiroptical characteristics of molecular liquid crystals of representative cellulose derivatives and then discuss recent efforts on the design and construction of functional material systems (such as stimulisensitive optical media and novel hybrids with minerals). These systems make use of the liquid crystalline molecular assembly of cellulosics. The survey of the other class of cellulosic liquid crystals deals with colloidal suspensions of CNCs obtained by acid hydrolysis of native cellulose fibers. Following the review of fundamental aspects related to the isotropic-anisotropic phase separation behavior of CNC suspensions, attention is directed to current applications of free-standing colored films, polymer composites reinforced with CNCs as mesofiller, and inorganic hybridizations using CNC chiral nematics as template. Some comments and the outlook for future explorations are also offered.

Chevrel compounds have been reexamined as potential positive electrodes for magnesium rechargeable batteries; their redox potential can be as high as about 2–3 V vs. Mg/Mg2+.

Various acylates and phenylcarbamates of (ethyl)­cellulose (EC) were synthesized by acylation and carbanilation, respectively, of the residual hydroxyls of an EC (ethyl DS = 2.50). The acyl substituents adopted were propionyl, butyryl, cyclohexanoyl, and adamantoyl groups, and the phenylcarbamoyl substituents included 3-chlorophenylcarbamoyl, 4-chlorophenylcarbamoyl, 3-methylphenylcarbamoyl, and bare phenylcarbamoyl groups. Chiral nematic mesophases of the EC derivatives, formed in chloroform, acetic acid (AA), and dichloroacetic acid (DCA), were examined by various optical techniques for evaluation of the helical pitch (P) in a set of absolute value and twist sense. The lyotropic samples prepared with DCA (20 °C) always assumed a right-handed chiral nematic structure, regardless of the degree of acyl (or phenylcarbamoyl) substitution (DSAcyl (or DSPC), ≤0.50). The chiral nematic series with AA (20 °C) and chloroform (5 °C) showed an inversion of the twist sense from being left-handed to right-handed, when DSAcyl (or DSPC) of each derivative was increased. The critical DS value for the inversion varied depending on the chain length, bulkiness, and polar nature of the employed substituent. For all of the lyotropic series explored, it was generalized that a temperature elevation strengthens a left-handed twisting power in each chiral nematic mesophase. Reversal of the twist handedness was also observed in a cycle of heating and cooling of some chiral nematics in AA. This was interpreted as being due to compensation in the strength of the two chiral interactions, i.e., steric repulsion and dispersion interaction between mesogenic molecules, contributing in mutually opposite signs to the twisting power (2πP –1) of the mesophase.

Calcium phosphate mineralization was conducted by using polymer composites of liquid-crystalline (ethyl)cellulose (EC) or (hydroxypropyl)cellulose (HPC) with poly(acrylic acid) (PAA) as a scaffolding medium for the inorganic deposition. The EC/PAA and HPC/PAA samples were prepared in colored film form from EC and HPC lyotropic liquid crystals of left-handed and right-handed chiral nematics, respectively, by polymerization and cross-linking of acrylic acid as the main solvent component. The mineralization was allowed to proceed in a batchwise operation by soaking the liquid-crystalline films in an aqueous salt solution containing the relevant ions, Ca(2+) and HPO4(2-). The calcium phosphate-deposited EC/PAA and HPC/PAA composites (weight gain, typically 15-25% and 6-11%, respectively) retained the chiral nematic organization of the respective original handedness but exhibited selective light-reflection of longer wavelengths relative to that of the corresponding nonmineralized samples. From X-ray diffraction and energy-dispersive X-ray spectroscopy measurements, it was deduced that the calcium and phosphorus were incorporated inside the polymer matrices in three forms: amorphous calcium phosphate, hydroxyapatite, and a certain complex of PAA-Ca(2+). Dynamic mechanical analysis and thermogravimetry revealed that the inorganic hybridization remarkably enhanced the thermal and mechanical performance of the optically functionalized cellulosic/synthetic polymer composites; however, the effect was more drastic in the EC/PAA series rather than the HPC/PAA series, reflecting the difference in the deposited mineral amount between the two.