Proton exchange membrane water electrolysis (PEMWE) is a promising approach for high-purity hydrogen production. In this study, Aquivion membranes modified by Argon (Ar) plasma and coated with a thin layer of TiO₂ by ALD technique were investigated. Ar plasma pre-treatment was applied to Aquivion membranes for varying durations ranging from 300 to 1800 seconds, and TiO₂ nanofilms were grown onto the treated membranes using TiCl₄ and H₂O as precursors in the ALD technique. The performance of the resulting hybrid membranes in terms of proton conductivity, surface wettability, water uptake, ion exchange capacity (IEC), and hydration number was evaluated. The results showed that increasing the duration of Ar plasma significantly increased the proton conductivity of the Aquivion membranes, from 0.0066 (S/cm) for the neat membrane to 0.0295 (S/cm) for the Aquivion 1800s membrane. The maximum IEC value was observed for the Aquivion 1080s membrane as 1.21 (meq/g), compared to 1.10 (meq/g) for the neat membrane. Furthermore, the presence of TiO₂ on the surface and inside the membranes directly affected their hydration numbers. Similarly, the water uptake of the membranes increased with increasing plasma process time, while the contact angle remained the same due to the uniform TiO₂ film on the surface of each membrane. In conclusion, the modified Aquivion membranes with TiO₂ thin films exhibited improved proton conductivity and IEC, making them promising candidates for use in PEMWE for high-purity hydrogen production.