Patent ID: 8701927

Claim:
A boiler comprising: a boiler vessel for containing a liquid and having an interior metal surface; and a superhydrophilic film comprising anionic silica on the metal surface, wherein a majority of the silica has a particle size no greater than 100 nm, wherein the superhydrophilic film has an open interconnected pore network with an average pore diameter of less than 150 nm, and wherein the superhydrophilic film has (a) a surface roughness that increases wettability for liquid macrolayers so as to obstruct bubble coalescence on the superhydrophilic film and enhance critical heat flux from a heat source through the boiler vessel and the superhydrophilic film to the liquid and (b) a network of non-wettable cavities that serve as bubble nucleation sites so as to promote nucleate boiling and a high heat-transfer coefficient.