The plinths of hydrogen-bonding in liquid crystals: Carboxylic acids as proton donors to emphasize on the hydrogen bonding in liquid crystals

The study of soft and condensed matter, specifically liquid crystals, has a rich history that spans from world wars to modern virtual reality. Liquid crystal materials are utilized in various applications such as displays, sensors, and more. Additionally, studying the unique properties of these anisotropic materials is intriguing. Our team of researchers is dedicated to creating sustainable, eco-friendly, and cost-effective organic materials. To achieve this goal, we focus on designing and synthesizing organic liquid crystals. An area we find fascinating is the creation of hydrogen-bonded liquid crystal supramolecular structures. Aromatic carboxylic acids are at the forefront of realizing hydrogen-bonded liquid crystals. The impact of alkyl/alkyloxy groups and substituents on acid's proton donating ability and acidic nature, contributing to mesomorphism, is fascinating. When alkyl/alkyloxy substituted benzoic acids interact with proton acceptors through hydrogen bonding, it causes significant variations in liquid crystalline phases obtained in the new supramolecules. This systematic review categorizes how electron-donating chains in alkyl/alkoxy-substituted benzoic acids contribute to mesomorphism, while electronwithdrawing substituents in non-mesogenic benzoic acids affect mesomorphism. The report discusses a detailed update of various donor acid moieties about their structure-LC phase correlation, with DFT calculations used to determine the H-bond length that supports the observations.