Flow-directed assembly of non-spherical titania nanoparticles into superhydrophilic thin films
Abhijeet OJHA1,Manish THAKKER2,3,Dinesh O. SHAH3,4,Prachi THAREJA5,*()
1. Department of Biological Engineering, Indian Institute of Technology, Gandhinagar, Ahmedabad 382424, Gujarat, India 2. Department of Instrumentation and Control Engineering, Dharmsinh Desai University, Nadiad 387001, Gujarat, India 3. Shah-Schulman Center for Surface Science and Nanotechnology, Dharmsinh Desai University, Nadiad 387001, Gujarat, India 4. Department of Chemical Engineering and Department of Anesthesiology, University of Florida, Gainesville, FL 32608, USA 5. Department of Chemical Engineering, Indian Institute of Technology, Gandhinagar, Ahmedabad 382424, Gujarat, India
Superhydrophilic thin films of 21 nm sized non-spherical titania nanoparticles are fabricated from a colloidal suspension by fixed blade flow coating without UV illumination. At a blade angle of α = 36° and a gap of d= 300 μm, hierarchically structured films with increasing surface roughness along with microscopic voids are formed depending on the substrate velocity and the titania volume fraction. Increasing the roughness is shown to be concomitant to an increase in the hydrophilicity, eventually leading to superhydrophilicity or water contact angle less than 5°.
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