Why nanocoatings make electronic devices waterproof

Nano-coating is a transparent thin-film nano-coating with a thickness of 50-800 nanometers, about one-thousandth the diameter of a human hair. The low convex surface of the nano-coating can adsorb the surrounding gas molecules to form a layer of stable thin film air cushion, avoiding the direct contact between the PCB surface and the metal material of the component pins and water molecules. On the PCB surface to form a very fine mesh film layer, effectively reducing the circuit board and electronic components surface energy, so that the water droplets deposited on the PCB surface contact angle tends to maximize, the PCB surface shows strong superhydrophobic properties.

As the pore size of the nano-coating membrane layer surface is much smaller than the water molecules, so that it can not naturally infiltrate, so the formation of a waterproof effect similar to a lotus leaf holding water droplets, that is, usually referred to as the superhydrophobic lotus leaf effect.

The upper surface of the lotus leaf is covered with very many tiny convex surfaces, the average size of the convex surfaces is about 6-8 microns, the average height is about 11-13 microns, and the average spacing is about 19-21 microns. Among these tiny convex surfaces there are also some larger convex surfaces with an average size of about 53-57 micrometers, which are also composed of microscopic bumps of 6-13 micrometers in size clustered together. The convex surfaces are all flattened at the tip and slightly concave in the center. These convex structures are very difficult to detect with the naked eye as well as with an ordinary microscope, and are often referred to as multiple nano- and micrometer-sized ultrastructures. These large and small bumps and protrusions on the surface of the lotus leaf are like a "hillock" that rises one by one, and the concave part between the "hillocks" is filled with air, so that a very thin layer of air, only nanometers thick, is formed on the immediate surface of the leaf.

The minimum diameter of water droplets is 1-2 mm (1 mm = 1000 microns), which is much larger than the convex surface of the lotus leaf, so the rain falls on the leaf surface, separated by a layer of very thin air, can only form a few points of contact with the top of the leaf surface on the "hillock", and thus can not be infiltrated into the surface of the lotus leaf.

Like the lotus leaf, the extremely fine nanostructure can also form a layer of breathable protective film, effectively reducing the surface energy of the object, can achieve the effect of ultra-high hydrophobicity, so as to achieve the purpose of waterproofing. Nano waterproof coating is more often used in electronic products PCB board, can effectively hydrophobic, prevent moisture, sweat on the erosion of electronic components.