THE PRINCIPLE OF NANO TECHNOLOGY
Lotus leaf has self-cleaning properties that is ultra-hydrophobic. Dirt particles are picked up by water droplets due to the microscopic architecture on the surface, which minimizes the droplet's adhesion to that surface
By mimicking nature in a general way, nano technologists have developed nano coatings that can stay dry and clean themselves by replicating in a technical manner the self-cleaning properties of the lotus leaf.
Type of repellent effects
While both hydrophobic and hydrophilic coatings can be utilized to reduce surface friction, there are key differences between the two to help determine which is the best option for your circumstances.
Hydrophobic means ‘water fearing’ but in a practical sense it relates to a surface having the ability to repel water meaning that there is essentially no interaction between water molecules and hydrophobic surfaces, known to be non-polar. Hydrophilic means ‘water loving’, which means these surfaces can attract and interact with water molecules, hydrophilic substances are said to be polar.
WATER CONTACT ANGLE
What does it mean?
When it comes to determining whether a surface is hydrophobic or hydrophilic, it is the contact angle of water on the surface that helps to define this– contact angle refers to the angle between the edge of a droplet and the surface it is on. A hydrophobic surface will have a contact angle of more than 90 degrees as the surface attempts to repel the water droplet, this will usually lead to any water remaining in a spherical shape on the surface. On the other hand, a droplet on a hydrophilic surface will have a contact angle of less than 90 degrees due to the surface interacting with the fluid and this can be shown by water spreading across the surface.
WATER SLIDING ANGLE
What does it mean?
Water sliding angle is measured by observing water droplets move on a surface at certain degrees. Lower sliding angle means the surface is more slippery, it tends to allow water droplet to release from the surface quicker, therefore improving cleanabillity.