Sol-gel based antireflective coatings using alkyltrialkoxysilane binders having low refractive index and high durability

A sol-formulation for forming a sol-gel, comprising:

• an alcohol containing solvent;
• an acid or base containing catalyst;
• an alkyltrialkoxysilane-based binder having the formula:
• wherein R1, R2, and R3 are the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, or an aralkyl group containing 7 to 20 carbon atoms;
• wherein R4 represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms, or a fluoro-modified alkyl group containing 1 to 20 carbon atoms;
• and
• silica based nanoparticles, wherein a mass ratio of the alkyltrialkoxysilane-based binder to the silica based nanoparticles is between 0.1:1 to 20:1.

A method of making a sol-gel comprising:

• forming a sol-formulation comprising:
• an alkyltrialkoxysilane-based binder having the formula:
• wherein R1, R2, and R3 are the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, or an aralkyl group containing 7 to 20 carbon atoms;
• wherein R4 represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms, or a fluoro-modified alkyl group containing 1 to 20 carbon atoms, and
• silica based nanoparticles;
• wherein a mass ratio of the alkyltrialkoxysilane-based binder to the silica based nanoparticles is between 0.1:1 to 20:1;
• an acid or base containing catalyst;
• and
• an alcohol containing solvent.