Why is tert-butanol the only C4 alcohol that is fully miscible with water, and what does that mean for its solvent role?

Why is tert-butanol the only C4 alcohol that is fully miscible with water, and what does that mean for its solvent role?
Tert-butanol's complete water miscibility sets it apart from n-, iso-, and sec-butanol, whose water solubility rises progressively with branching. The spherical shape of the tert-butyl group minimizes hydrophobic surface area, lowering the energy penalty when dispersing in water. Additionally, the three methyl groups donate electron density to the hydroxyl oxygen, strengthening hydrogen bonding with water. This unique solubility profile makes TBA a versatile co-solvent in coatings, adhesives, and pharmaceutical formulations, where it prevents film blushing and aids in dissolving both polar and non-polar actives. Its low freezing point and volatility also support its use in freeze-drying and as a process solvent.