Preparation and cholesteric mesophase properties of (Butyl-co-pentyl) propylcellulose

Abstract

Butyl and pentyl ether derivatives of (2-hydroxypropyl) cellulose (HPC) and butyl/pentyl mixed ethers of HPC (BPPC) with different alkyl compositions were prepared in nonaqueous solution and their thermotropic cholesteric properties examined. The temperature dependence and the composition dependence of the optical pitch, nP, were then determined for all of the ether derivatives. The molecular conformation and chirality of BPPC appeared to be to be variably smooth with the side chain composition of the polymer. The response rate of cholesteric configurational change of the thermotropic mesophases arising from a temperature jump from 45 to 75°C, was also determined. The transformation of the cholesteric mesophase formed by an equimolar ether derivative (BP-50) was faster than that of the cholesteric one formed by a single-alkyl (pentyl) ether derivative (BP-0). This seemed to be a general result reflecting a pseudo-copolymer effect of cellulose derivatives on the properties of their thermotropic cholesteric mesophases.

Thermotropic liquid crystalline properties of (hydroxypropyl)cellulose derivatives with butyryl and heptafluorobutyryl substituents

“…50-70 wt% Gray 1976, 1980). With regard to thermotropic liquid crystals realized in melt without any solvents, several derivatives of HPC obtained by esterifying or etherifying the hydroxyl groups of HPC were reported to form stable chiral nematic phases that displayed iridescent colors over a range of temperatures (Guittard et al 1994;Hou et al 2000;Huang et al 2007;Ishizaki et al 2015;Kosho et al 1999;Ohlendorf and Greiner 2015;Ritcey and Gray 1988;Tseng et al 1981;Yamagishi et al 1994;Yamagishi et al 2006). Those HPC ester/ether series can serve as media for a thermal sensor, or a display or light reflection device adaptable to various temperature conditions.…”

Cholesteric Liquid Crystals from Cellulose Derivatives with Alkyl Ether Groups

“…After stirring for 30 minutes at 65 ºC, powdered NaOH (5 eq) was added quickly. After stirring for 2 hours under dried N 2 atmosphere, 1-bromobutane (3.5 eq) was added again and the reaction mixture was stirred at 65 ºC for 48 hours [23]. When the reaction mixture was poured into water, yellow-sticky product was precipitated.…”

Liquid Crystals of Cellulosics: Fascinating Ordered Structures for the Design of Functional Material Systems

“…Subsequently, the same group indicated that several ethers and esters of HPC obtained by etherifying or esterifying the hydroxyl groups of HPC can form stable chiral nematic phases (typically with a right-handed twisted), some of which imparted reflection colors at ambient temperatures [3,4]. In the 2000s, a few efforts on thermotropic behavior were conducted for longer alkyl esters [34,35] and ethers [36] of HPC (see Scheme 1).…”

“…Yamagishi et al [36] prepared butyl ether (C4-O-PC), pentyl ether (C5-O-PC), and butyl/pentyl mixed ether (C4/C5-O-PC) derivatives of HPC at DS % 3 (for the newly introduced substituent) and examined the temperature dependence of the pitch P of their chiral nematic thermotropics. All the thermotropics indicated a positive dependence of P with increasing 252 Y.…”