To investigate the effect of spacer length and linkages between the rigid mesogenic core and the terminal group on the molecular interaction and physical properties of polymers, two series of novel side chain liquid crystalline polyacrylates were synthesized. These were composed of liquid crystalline monomers with six or eleven methylene segments as spacers, and chiral monomers end capped with menthyl or cholesteryl groups. Liquid crystalline phases of the polymers were investigated using differential scanning calorimetry and polarized optical microscopy, and confirmed with X‐ray diffractometry. Color image recording of the synthesized polymer films was achieved using a thermal treatment, and then fixed by quenching. This investigation demonstrates that the introduction of carbonate linking groups between the rigid mesogenic core and terminal group decreases both the lateral molecular interaction and thermal stability of the liquid crystalline polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6214–6228, 2008

2007) Photochemical tuning capability of cholesteric liquid crystal cells containing chiral dopants end capped with menthyl groups, Liquid Crystals, 34:7, 891-902,In order to investigate the photochemical tuning capability of chiral monomers and polymers containing end-capped menthyl groups, a new series of chiral dopants was synthesized and added to commercially available nematic liquid crystals to induce cholesteric liquid crystal (LC) phases. The addition of chiral dopants with azo structure led to phototunability of the reflection colour of the LC cells. Photochromic variation of the LC cells due to photoisomerization of the azo compound was investigated. After photopolymerization of the monomers inside the cholesteric LC cells, the centre wavelength of the reflected band of the incident light was found to be fixed and the reflected bandwidth was broadened, resulting in a red shift. A schematic representation of both the photoisomerization of the azo dopants and its effect on variation of twisting pitches is proposed. Real image recording was performed using 365 nm UV through a mask with text. The top and side views of the morphological network structures of a fabricated cholesteric LC cell were investigated using scanning electron microscopy. The results of this investigation demonstrated that RGB reflected colours of LC cells can easily be achieved through the addition of the menthylcontaining synthesized chiral compounds to nematic LCs. The addition of synthesized AzoM helped further in recording the patterns onto cholesteric LC films using 365 nm UV exposure.

To estimate the effects of diastereomeric copolymers as photoresists, diastereomeric copolymers containing chiral and racemic bornyl methacrylates (BMAs) were synthesized. Both alicyclic BMAs were synthesized from (2)-borneol and (6)-borneol, and then copolymerized with t-butyl methacrylate (t-BMA), tetrahydro-pyranyl methacrylate (THPMA), and a-methacryloxy-g-butyrolactone (MABL). The glass transition temperature of the copolymers was found to increase with an increase in the content of alicyclic bornyl groups in the copolymers. To investigate the effect of both the alicyclic butyrolactone and the bornyl groups on photosensitivity, thermal property, and etching resistance, the synthesized alicyclic copolymers were used to prepare photoresists with photoacid generators. The sensitivity and the contrast of the photoresists were calculated. This investigation demonstrated that the existence of alicyclic butyrolactone and bornyl groups increases the etching resistance of photoresists. It was also found that high stereo hindered bornyl structures disturb and restrict the mobility of the polymer chain, leading to an increase in the thermal stability of the polymers. A real pattern recording of photoresists with PR3 composition was performed; an optimal sensitivity of 20 mJ/cm 2 and resolution of 1 lm of positive tone photoresists with 1 lm thickness was achieved.

No abstract