Thermotropic Liquid-Crystalline Polymers

Influence of chemical structure on the optical properties of new side-chain polymers containing cholesterol

“…The ΔH derived from the T ic of the sample prepared in this study is approximately 1.0-1.5 J/g, which is within the limits of low-molarweight [26][27][28][29] and cholesteric polymer liquid crystals. [11][12][13][14][23][24][25] However, the thermal stabilities of the cholesteric phases of the samples differ slightly: the T ic of PHES is higher than that of PHET. This result means that the thermal properties of the cholesteric phase sensitively depend on the difference in the chemical structure between the alkylene spacer and the cholesteryl group.…”

“…1288 S.Y. Yang et al Table 1 summarises the thermal properties of PHET and PHES; the previously reported thermal properties of PChA-n [11,[13][14][15] are included for comparison. The ΔH derived from the T ic of the sample prepared in this study is approximately 1.0-1.5 J/g, which is within the limits of low-molarweight [26][27][28][29] and cholesteric polymer liquid crystals.…”

“…This result means that the thermal properties of the cholesteric phase sensitively depend on the difference in the chemical structure between the alkylene spacer and the cholesteryl group. PChA-5 has been reported to form a smectic phase [11][12][13] at T g = 55-218°C and to form a cholesteric phase [11] as it cools. In contrast, PChA-10 (DP = 360) has been reported to form a smectic phase from T g = 35-148°C and to form a cholesteric phase within a narrow temperature range between 148°C and 153°C.…”

“…Numerous researchers have investigated the possibility of sidechain cholesteric polymers with cholesterol in different alkylene spacers. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] In particular, during the past few decades, many researchers have investigated the thermotropic cholesteric phase of flexible side-chain polymers with cholesterol, including polyacrylate, [11][12][13][14][15][16][17][18][19][20][21][22] polymethacrylate [11][12][13][16][17][18][19][20][21][22] and polysiloxane. [11][12][13][23][24][25] Side-chain homopolymers with a cholesteryl group in flexible spacers such as poly(cholesteryl-ω-acryloyloxyalkanoates) (PChA-n), [11][12][13] poly(cholesteryl-ω-methacryloylalkanoates) (PChM-n) …”

“…[11][12][13][23][24][25] Side-chain homopolymers with a cholesteryl group in flexible spacers such as poly(cholesteryl-ω-acryloyloxyalkanoates) (PChA-n), [11][12][13] poly(cholesteryl-ω-methacryloylalkanoates) (PChM-n) [11][12][13] and poly[4-cholesteryl-4′-(acryloyloxy-n-alkyloxy) benzoates] [14] form cholesteric phases in a narrow range and smectic phases in a wide range. In contrast, other homopolymers [11][12][13]15,16,[18][19][20][23][24][25] properties of the side-chain LC polymers with different chemical linkages to the cholesterol are investigated. We have also identified how the arrangements of different types of chemical linkages affect the optical properties in a cholesteric phase by comparing the results of this experiment with those related to PChA-n ( Figure 1).…”