How Does the Surface Energy of Structured Packing Affect Wettability?

structured packing, a critical tower internal in chemical separation processes, relies on surface energy to determine wettability. Surface energy, the energy of a material's surface, arises from intermolecular forces. High surface energy materials, like smooth metal or ceramic packings, have strong intermolecular attraction, causing liquids to spread easily—low contact angle (<90°), indicating good wettability. This ensures uniform liquid distribution across the packing, enhancing contact with gas phases for efficient mass transfer. Conversely, low surface energy materials, such as PTFE or certain polymers, exhibit higher contact angles (>90°), leading to poor wettability. Liquids may bead or form uneven films, causing channeling where gas bypasses liquid, reducing separation efficiency. Tower internal design often involves surface modification—e.g., coating or roughening—to adjust surface energy. For instance, adding a hydrophilic coating to low-energy packings improves wettability, while optimizing surface roughness in metal packings enhances liquid retention. In summary, controlling surface energy is essential to improving wettability, which directly boosts structured packing performance and overall separation process efficiency in chemical towers.