Reviewing Ferroelectric Nematic Liquid Crystals: From Fundamental Properties to Cutting-Edge Applications

Ferroelectric nematic (N_F) liquid crystals (LCs) have garnered substantial interest due to their unique polar ordering, phase transitions, and electro-optic (E-O) properties, with potential applications spanning from low-power reflective displays to advanced photonics and microfluidics. This review explores the multifaceted nature of N_F LCs and comprehensively analyzes their phase behavior, alignment, and surface interactions. Notable findings include the nematic (N)-N_F phase transition's weak first-order nature, surface treatments' role in inducing polar order, and meron-like structures resembling ferromagnetic domains. Furthermore, the review highlights the tunability of N_F LCs under electric fields, offering exciting possibilities for adaptive optics, sensors, and actuators. Despite these advancements, challenges remain in optimizing molecular alignment, controlling defects, and expanding the scalability of N_F LC technologies. By addressing key experimental and theoretical studies, this review aims to present a deeper understanding of N_F liquid crystals' E-O responses, phase transitions, and their potential to revolutionize future LC-based technologies.