BACKGROUND

Exemplary embodiments pertain to the art of hydrophilic coatings, more particularly, to multilayer hydrophilic coatings for spacecraft components.

Aircraft and/or spacecraft components, for example, heat exchangers aboard the International Space Station, use hydrophilic coatings in order to facilitate the collection of condensed humidity. Common coatings include, for example, zinc silicate with silver oxide as an antimicrobial agent. However, these coatings suffer from problems such as flacking, dissolution of the coating, and DMSD catalysis. Antifungal properties are also lacking. For example, fungal build up can necessitate frequent and undesired maintenance of the aircraft components.

Therefore, there is a need to develop a hydrophilic coating that avoids problems such as flacking, dissolution, DMSD catalysis, and fungal build up.

BRIEF DESCRIPTION

Disclosed is a multilayer hydrophilic coating, comprising: a base layer comprising oxide particles, wherein a shape of an oxide particle is a hollow, generally spherical shell; a topcoat layer deposited on the base layer, wherein the topcoat layer comprises a sol-gel; and a doping agent, wherein the doping agent is located within the topcoat layer, deposited on the topcoat layer, located between the base layer and the topcoat layer, or combinations thereof.

Also disclosed is a substrate coated with the multilayer hydrophilic coating.

Also disclosed is a method of making the multilayer hydrophilic coating, the method comprising: dip coating a substrate with a solution comprising the oxide particles to form the base layer; and dip coating and calcining the substrate with a solution comprising a sol-gel precursor to form the sol-gel and the topcoat layer; wherein the doping agent is included in the topcoat solution, the base layer solution, or combinations thereof; or the method further comprises dip coating and calcining the substrate with a solution comprising the doping agent.

