Thermal and optical behavior of poly(ethylene-b-ethylene oxide) block copolymer dispersed liquid crystals blends

• Polymer blends based on nematic liquid crystals were fabricated without any solvent.
• HOBC showed stronger miscibility with PEO block while EBBA with PE block.
• Solubility parameters confirmed miscibility between components.
• Investigated polymer blends maintained nematic liquid crystal character.

Different block copolymer dispersed liquid crystals blends based on poly(ethylene-b-ethylene oxide) (PE-b-PEO) and modified with low molecular weight nematic liquid crystals, 4′-(hexyloxy)-4-biphenylcarbonitrile (HOBC) and N-(4-ethoxybenzylidene)-4-butylaniline (EBBA) were prepared and characterized. The miscibility between each block of PE-b-PEO block copolymer and nematic liquid crystals was studied using differential scanning calorimetry (DSC). DSC results were in good agreement with the miscibility prediction supported by the solubility parameters and miscibility effect in polymer dispersed liquid crystals blends based on polyethylene oxide (PEO) homopolymer. Thermal stability of PE-b-PEO/HOBC and PE-b-PEO/EBBA blends was also studied. Block copolymer dispersed liquid crystals blends maintained the nematic/isotropic transition in function of the ratio between PE-b-PEO block copolymer and nematic liquid crystals indicating the potential application of the designed materials.

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