Bio-Mimicry

Self-Cleaning- A Biomimicry

How nature cleans itself?

If you ask anyone regarding why the plant leaves were acting as a repellent to water and the most major response is ‘a rough surface of leaves’. But what about a rough surface like Lotus (Nelumbo nucifera) which isn’t smooth at all yet a most predominant water repellent leaves in the world. Thanks to the exciting digital technologies exists which enable us to have an insight of nature.

Lotus leaf

                         

 

Lotus leaf  

        

 

Computer graphics on insight of hydrophobic nature

The hydrophobic (Repelling, tending not to combine with) nature of the lotus leaf enables it to stay away from the dirt.

Biomimicry

            Bio-mimic by the name itself suggests that it is the imitation of nature’s model,system and elements to solve the human challenges in this technical world. In other words, it is the innovations inspired from the nature. From a wide variety of models,let’s have a brief view of ‘Lotus Effect’.

Lotus Effect

            Superhydrophobocity effect is an combination of rough and hydrophobicity which generates a hydrophobic surfaces, enables it to bounce water and roll off  from the surface and helps them to clean themselves. Lotus effect nothing but refers to the self cleaning assets as a result of superior water repellant superhydrophobic nature exhibited by the leaves of Lotus (Nelumbo nucifera).

             Now, microscopically rough surface additives opens up a new generation of paints, glasses and fabric finishes which significantly reduced the need for chemical and labor cleaning.

Working mechanism

            ‘Contact angle’ is the one of the most facile technique to measure the wet nature of a surface or material. When the water makes contact with the surface, the surface behavior can be predicted nor measured by the angle between the surface and the tangent of the water surface. This angle is called ‘contact angle’.

                        To mimic a water repellant surface the material or surface should possess a contact angle should be tailored above 90^o since the smaller angle (<90) allows the water to spread onto the surface. But when the angle is large, the water gathers together and does not spread on the surface.

Self-cleaning molecular surfaces by Indian researchers

            M. B. Avinash and team have cultivated molecular surfaces with a special honeycomb like structure possessing superhydrophobic nature with the contact angle of 156^o which enabled it to free of stains and water. They have tested it for the potential applications in electronics and miniaturized biochemical assays.

Implementations

Self-cleaning glasses

             Researchers developed a thin film coating of titanium dioxide on a sodalime glass substrate and tested the properties. The first step is photocatalytic process where the ultraviolet rays from the sunlight influences the chemical reaction through which the decomposition of dust particles kicks off. Saint gobain, Pilkington Activ™ and many companies have utilized these properties and self-cleaning glasses were commercialized which drastically reduced the manpower, energy and cost of maintenance.

Lotus paints

            Researchers have developed dirt-free complex surface without any cleaners or energy which interacts with the physics of water molecules like wings of most large-winged insects like butterflies. Lotusan® exterior coating used these micro-structural principles in paints to regain its cleanliness automatically just by a rinse of rain showers.

            India has successfully erected E-toilets with super hydrophobic surfaces which enables them dirt-free and significantly reduced the labor charges as well as expenditures.

Image courtesy

Wikipedia

Online library Wiley

Biolinscientific

References

Wikipedia

Biomimicry

Asknature

I see India

Wiley indexed “Self-Cleaning Functional Molecular Materials” article

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