PVCL-intercalated samples containing nano-dimensional phases with η-modification of the TiO2−x·nH2O composition are obtained by hydrolysis of TiOSO4·xH2SO4·yH2O or TiOSO4·xH2O in the presence of poly(N-vinylcaprolactam) (PVCL). The incorporation of PVCL with water molecules into the interlayer space of the structure of the η-phase—TiO2−x·(PVCL nH2O)—is established by the X-ray diffraction study while the presence of PVCL in the sample composition is confirmed by the X-ray photoelectron and IR spectroscopy CHNS analysis and X-ray spectral microanalysis. Intercalated samples manifest the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. It is shown that the sample composition (the content of hydrated titanium dioxide) the composition of the η-phase (the presence of PVCL and H2O or the water content in the interlayer space of the structure), and the surface composition (S in the form of SO42− groups O in the form of adsorbed water and OH groups) affect the antimicrobial activity in the dark.