Antifogging, antireflective, and highly transparent coatings fabricated with SiO₂ and TiO₂ nanoparticles

Titanium dioxide nanoparticles (TNPs) and mesoporous silica nanoparticles (MSNPs) were synthesized using conventional sol-gel reactions. Antifogging, antireflective, and transparent coatings were fabricated on a glass substrate by depositing the TNPs, commercially available silica nanoparticles (SNPs), and the MSNPs according to a typical Layer-by-Layer (LbL) technique. First, the TNP thin film was deposited on a glass substrate. Thin films of SNPs of 7 or 22 nm particle sizes, named SNP7 and SNP22, respectively, were then deposited on the top of the TNP film by the LbL technique. Subsequently, the MSNP films were then coated on the SNP films by the LbL technique. The multifunctional performance of several coatings of different structures was investigated by measuring the transmittance, reflectance, and contact angle. From the results, the best performance was shown with the coatings of seven layers of SNP7 (i.e., TNP+SNP7₇ +MSNP₂) and three layers of SNP22 (i.e., TNP+SNP22₃ +MSNP₂). A superhydrophilic property (contact angle < 5°) was observed with all the coatings tested, which even improved with some coatings containing MSNPs. The coating with the best performance, TNP+SNP7₇ +MSNP₂, showed an excellent antifogging characteristic under a highly fogging condition.