Advanced Physical Research

A broad-temperature-range smectic C (SmC) phase is desirable for the development of host materials for ferroelectric liquid-crystal systems. In this work, binary and multicomponent mixtures of ester-based thermotropic liquid crystals, denoted A(n;k), were investigated to determine how molecular structure and composition influence the thermal stability of the SmC mesophase. Phase sequences and transition temperatures were identified by polarized optical microscopy and differential scanning calorimetry. The results reveal systematic structure–phase relationships. Mixtures of homologues with equal total alkoxy-chain length, n+kn+k, generally preserve or slightly increase the upper stability limit of the SmC phase, whereas molecular-length mismatch tends to depress this boundary. Lower-temperature stability is enhanced when an appropriate terminal-chain mismatch suppresses crystallization. Further broadening is achieved by combining A(n;k) homologues with the strongly smectogenic component C-2. The optimized composition A(10;6)/A(8;6)/A(10;4)/A(8;4)/C-2 = 1:1:1:1:2 exhibits the phase sequence Cr 16 °C–SmC 61 °C–SmA, corresponding to an approximately 45 °C-wide SmC interval encompassing room temperature. The observed behavior is interpreted in terms of molecular packing, steric effects, and intermolecular dipolar interactions. These results establish a practical mixture-design strategy for stabilizing broad-temperature-range SmC hosts and for subsequent induction of ferroelectric SmC* behavior through polar chiral doping.