How can cooling an ordinary liquid produce a nematic liquid crystal phase?

Cooling an ordinary liquid can produce a nematic liquid crystal phase through a process of symmetry-breaking phase transitions. As the temperature of a substance in the liquid state decreases, matter tends to evolve from highly disordered states toward more ordered states.1

In an ordinary liquid, molecules possess full continuous translational and rotational symmetry, meaning they are disordered in both position and orientation. As the temperature is reduced, the system undergoes a rotational symmetry-breaking transition. During this process, elongated, rodlike molecules begin to align along a common axis, known as the director.1

This alignment is driven by the need to minimize collisions; when rodlike molecules align, they gain greater freedom to move along the direction of their long axes before encountering a neighbor, compared to the restricted movement they experience when randomly oriented. While the molecules in the resulting nematic phase remain disordered in their positions, their orientations become nearly parallel, effectively breaking the continuous rotational symmetry of the isotropic liquid.1