• • The optimized PDMS:Cu mass ratio of 2:1 yields a condensation HTC of 5.85× smooth copper at ΔT = 1 K, a 2.76× improvement over pure PDMS, directly addressing interfacial thermal resistance in condensers. Industrial adoption could reduce heat exchanger surface area by ~40% for equivalent duty, lowering capital expenditure.
• • Mechanical durability: after 45 sandpaper abrasion cycles (800# grit, 90 g load), WCA remains 149°, and after 240 g sand impact, WCA is 147.7° with WSA 18.5°. This exceeds typical polymer coatings that fail below 20 cycles, enabling deployment in abrasive steam environments such as power plant condensers.
• • Thermal stability: 300 °C for 12 h maintains WCA >151.8° and WSA <9°, attributed to PDMS pyrolysis forming SiO2 and siloxane oligomers. This permits integration into high-temperature processes (e.g., industrial drying, waste heat recovery) without degradation.
• • Steam exposure for 9 h maintains superhydrophobicity (WCA >151.4°, WSA <9°); after 12 h, WCA drops to 124.2° but recovers to >151° via 100 °C for 2 h. This self-healing-like recovery reduces maintenance downtime and extends operational lifetime in condensing steam applications.