Nanocomposites with tunable dielectric properties: BaTiO3 loaded cellulose nanocrystal-liquid crystalline polymers

Abstract

Dielectric nanocomposites are emerging as next-generation energy storage materials due to their applicability in advanced electronics, renewable energy systems, and electric vehicles. In this work, we report the rational molecular design, synthesis, and structure–property investigation of a BaTiO₃/cellulose nanocrystal (CNC)-liquid crystal polymer (LCP) nanocomposite with enhanced dielectric performance. The hybrid platform integrates BaTiO₃ nanoparticles dispersed within a cyanobiphenyl-based polyacrylate matrix (PAACB12-r-PAA), followed by in situ interlocking with CNCs. This biomaterial-supported anisotropic system, exploits both the permanent dipole of smectic cyanobiphenyl liquid crystalline mesogens and ordering of CNC-LC materials to induce hierarchical self-assembly and promote strong dielectric responses. Films are fabricated through hot-pressing at the liquid crystalline transition temperature (T_LC), followed by rapid quenching to lock in the alignment. We systematically investigate the influence of processing parameters such as BaTiO₃ concentration, LCP alignment, and thermal treatment on dielectric behavior. Temperature-controlled small-angle X-ray scattering (TSAXS), broadband dielectric spectroscopy, and microscopy are employed to correlate mesophase orientation, dispersion quality, and molecular interactions with the dielectric constant, breakdown strength, energy density, and dielectric loss. Our findings reveal that the liquid crystalline matrix not only enhances BaTiO₃ dispersion and interfacial polarization but also facilitates structural ordering that improves the composite's dielectric performance. The permanent dipoles within the LCP matrix further augment polarization via Ti⁴⁺ displacement from the O²⁻ octahedra in BaTiO₃, offering tunable dielectric enhancement. This work establishes a general strategy for designing multifunctional dielectric nanocomposites by integrating mesogen alignment, nanofiller anisotropy, and optimized processing to achieve tunable dielectric performance for advanced electronic applications.