Brief histroy of Superhydrophilicity of Titania "Akira Fuijishima"

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Titania is white powder pigment used in various purpose in day to day life like cosmetics, sunscreens, food, pharmauctic and various application. Mainly Titania was used as Photocatalyst for dye degradation, water splitting, CO2 reduction which applications where most dominant properties of titania was found by 
Professor Kazuhito Hashimoto and his student Akira Fujishma 
at University of Tokyo. the history was begun before half centuries.


Discovery of Honda-Fujishima Effect

Akira Fujishma was a grad student work with his supervisor found out using titania single crystal and copper wire with epoxy resin, when he apply water and passed sunlight through the system he observed air bubbles. He was excited to see the bubbles. then they found out production of oxygen water was separated they separate hydrogen from water. 


Photocatalysis
In 1972, the discovery that TiO2 photocatalysed decomposition of water was announced. With white pigment  showed an great surprise Fujishima defensed his doctoral thesis.  

When light strike to Titania photocatalyst electron inside where went to higher energy band called conduction band and in ground state holes are formed. that electron is donated to another molecules is called reduction. Freely moving hole also gain  electron from  pollutant is called oxidation.
which can further oxidize alcohols, plants leaves and even cockroaches.

Superhydrophilic nature


In 1989, Dr. Hashimoto joined his group, he gazed at yellowed toilet bowl on the University of Tokyo. If the photocatalyst could decompose the roaches then why not in bacteria? A small amount of material is enough for bacteria removing from yellowing toilet. they needed to collaborated with industries but at that time government of Japan put a lot of restriction between research in academia. So they did there research in Saturday and Sunday. At that time they found out Superhydrophilicity which means material has zero contact angle of water.

it was an amazing breakthrough Titania was used to coated in mirrors  for defog glass and self cleaning glass, car mirrors, building windows etc.

Titania was coated on the surface is extremely wettable, the surface water forming a flowing thin film. this result of grease and grim were removed easily.

Inspire mind develope the society 
 
Myself Rajakani, PhD student from India

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