Sol-gel coating methods and thin film coated substrates therefrom

Abstract

A method for depositing sol-gel derived coatings on substrates to form coated substrates includes the steps of providing a first solution including at least one sol precursor and at least one solvent. A water comprising solution is added to the first solution to form a sol-gel. The sol-gel is deposited on a substrate. The sol-gel layer on the substrate is dried/cured at a temperature ≦100° C. for at least 10 minutes to form a solid layer, wherein the solid layer has a thickness from 50 nm to 110 nm. The depositing and curing steps are repeated at least once until combined thickness of the solid layers forms a coating of a predetermined thickness. The resulting solid layers are low water content layers that can be evidenced by transmission measurements. The coated substrate can be an IR transmissive substrate having a recrystallization temperature <130° C. and each of the solid layers provide a transmission at λ=2950 nm, normal incidence and 1 mW power if placed on the IR transmissive substrate of ≧99% of the transmission directly through the IR transmissive substrate.