In the R&D of beauty creams, the selection of polyols (fatty alcohols) often puzzles formulators: why is high-melting-point pure C18 stearyl alcohol 反而 difficult to form a cream? Classic research by Professor G.M. Eccleston from the University of Strathclyde in the UK reveals the answer—fatty alcohols are the "soul" of building lamellar gel networks, not just thickeners. Studies show that in non-ionic emulsifier systems, pure C18 alcohol has a dense crystal lattice, making it difficult for emulsifiers to insert and form a swollen structure. After 30 days, it easily turns into a mobile liquid and demulsifies. In contrast, C16/18 mixed alcohol, with lattice defects created by "long and short chains", allows emulsifiers to penetrate smoothly, forming a stable semi-solid cream with steadily increasing viscosity. Microscopic observations confirm that C18 alcohol crystals remain sharp-edged 24 hours after contact with emulsifiers, while the mixed alcohol system forms a dense gel network within 6 hours. The ionic emulsifier system shows the opposite: electrostatic repulsion can force open the lattice of pure C18 alcohol to form a high-viscosity cream. However, experts warn that pure C18 alcohol is prone to crystal coarsening during long-term storage, and C16/18 mixed alcohol remains a reliable choice for balancing stability and skin feel. The formulator's practical guide states that C16/18 mixed alcohol is preferred for regular face creams; C22 behenyl alcohol can be compounded to improve heat resistance; high-purity fatty alcohols should be avoided in non-ionic systems. Understanding the liquid crystal network theory is the key for formulators to move from "empirical operation" to "scientific R&D".