What surface energy characteristics affect liquid repellency in composite materials?

The liquid repellency of composite materials is heavily influenced by their surface energy characteristics. Surface energy, defined as the excess energy at a material's surface compared to its bulk, plays a critical role in determining wettability and liquid interaction. Low surface energy materials, such as those with hydrophobic or superhydrophobic coatings, exhibit strong liquid repellency due to minimized adhesion forces. Key factors include surface roughness, chemical composition, and hierarchical micro-nanostructures, which collectively reduce liquid-solid contact area. Understanding these properties enables the design of advanced composites for applications like self-cleaning surfaces, anti-icing coatings, and waterproof textiles. Optimizing surface energy through material engineering ensures enhanced performance in demanding environments.