Hydrophilic coatings, articles, coating compositions, and methods

A kit for modifying a substrate surface, the kit comprising:

• at least one container comprising a first composition comprising:
• inorganic nanoparticles comprising colloidal silica, colloidal zirconia, colloidal alumina, colloidal ceria, colloidal tin oxide, or colloidal titanium dioxide, the inorganic nanoparticles having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
• amine groups, protected amine groups, or combinations thereof;
• optional hydrophilic groups;
• an optional surfactant;
• and water;
• wherein the first composition comprises 0.1 wt-% to 30 wt-% inorganic nanoparticles;
• and
• at least one container comprising a second composition comprising:
• nanoparticles comprising functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
• amine-reactive groups;
• optional hydrophilic groups;
• an optional surfactant;
• and water;
• wherein the first and second compositions when combined, applied to a substrate, and dried, provide a hydrophilic coating on the substrate that demonstrates improvement, relative to an uncoated substrate, in at least one characteristic selected from the group consisting of antifogging, antireflective, easy-cleaning, and antistatic characteristics.