Synthesis and phase behavior of chiral liquid crystalline polymeric networks derived from menthol

Abstract

The synthesis of new chiral monomer 4-(menthyloxyacetoxy- benzoyloxy)biphenyl-4′-(2-(undec-10-e noyloxy)ethoxy)benzoate (ML), crosslinking agent 4-(undec-10-enoyloxy)biphenyl-4′-(2-(undec-10-enoyloxy)ethoxy)benzoate (CA), and liquid crystal polymer networks (E1−E5) containing menthyl group is presented. Their chemical structures and phase behavior were characterized with Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), elemental analyses, polarizing optical microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), and X-ray diffraction. The selective reflection of light for ML was investigated with ultraviolet/visible/near infrared (UV/Visible/NIR). By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, MLcould form mesophase and show a chiral smectic C phase, cholesteric phase and cubic blue phase. CA displayed a smectic A phase and nematic phase. The polymer networks containing less than 12 mol% of the crosslinking units showed reversible cholesteric phase transition, wide mesophase temperature range, and excellent thermal stability. With increasing the content of crosslinking unit, the corresponding Tg increased, the Ti decreased, and the mesophase temperature range narrowed for E1−E5. TGA showed that the Td(5%) was greater than 330°C for E1−E5.

Preparation and properties of P(AN-co-AM)-g-MAPEG phase-change nanofibers

“…Therefore, the use of blends, grafting, and other means that can make solid-liquid PCM turn into a solid-solid PCM is gaining significance. [4][5][6][7] Among these methods, the macromonomer method is attractive because of the high grafting rate, and the composition of the graft copolymer can be controlled by adjusting the proportion of the macromonomer and the monomer in PCMs. 8 PCMs can be grafted to the main chain by macromonomer technology and the resulting composite retains its solid shape during the transition.…”