With the ever increasing demand and availability of every day electronic devices in various exotic applications like smart phone and wearable electronics etc. there is a great concern about the compatibility and safety of such electronic devices from water. We have to be very careful towards the safety of any electronic device due to its exposure to water as it is considered one of the major causes of its (electronic device) malfunctioning. Electronic devices with washing abilities are in demand as it may enhance their functionality and usability. Imagine when devices of our daily use like smart phone etc. could be washed along with the rest of the laundry. Researchers are currently working on what could be possible in this direction and it is not too distant future.

Hydrophobic electronic materials

Hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is seemingly repelled from a mass of water. (Strictly speaking, there is no repulsive force involved; it is an absence of attraction.) Surfaces that repel water, like the leaves of the Colocasia plant, are called hydrophobic. Nonpolar molecules that repel the water molecules are said to be hydrophobic; molecules forming ionic or a hydrogen bond with the water molecule are said to be hydrophilic. Microscopic textures play a huge role in hydrophobicity. For example, the leaves of the Colocasia plant are covered with waxy, microscopic bumps that prevent water drops from being able to stick, or adhere, to the leaf. As a bonus, the water drops collect dust and dirt as they roll along the leaf—in other words, the leaf surface is self-cleaning. Inspired by some plants’ ability to stay dry, scientists have designed innovative super-hydrophobic metal surfaces. These new metal surfaces can be used to make vehicles that don’t rust and airplane wings that don’t get icy. In case of wearable electronics, the fiberglass, plastic, and metal comprising most circuits can handle getting wet and a bit of agitation, but batteries should never be bent, shorted, or be subject to water or heat.  A new way to create electronic circuits using water-repellent graphene could pave the way for a new class of washable electronics. Researchers from Iowa State University have developed new graphene printing technology that can produce electronic circuits that are low-cost, flexible, highly conductive and water repellent, which would be attractive in a number of applications. The researchers used inkjet printing technology to develop electric circuits on flexible materials. They used flakes of graphene to create the inks used in the study. While graphene is a great conductor of electricity and heat, the printed flakes are not highly conductive and must be processed to remove the non-conductive binders and then welded together to boost conductivity and make them useful for electronics or sensors. That process usually involves heat or chemicals, but the researchers developed a rapid-pulse laser process that treats the graphene without damaging the printing surface— even if it is paper. The laser processing technology can also take graphene-printed circuits that can hold water droplets and turn them into circuits that repel water. By micro-patterning the surface of the inkjet-printed graphene, the laser aligns the graphene flakes vertically – like little pyramids stacking up which induces the hydrophobicity. Researchers have found application of their laser processing technology: taking graphene-printed circuits that can hold water droplets (hydrophilic) and turning them into circuits that repel water (superhydrophobic). According to researchers, the energy density of the laser processing can be adjusted to tune the degree of hydrophobicity and conductivity of the printed graphene circuits.

The nanotechnology would lend enormous value to self-cleaning wearable/washable electronics that are resistant to stains, or ice and biofilm formation. The new technology could be used in a number of applications including flexible electronics, washable sensors in textiles, microfluidic technologies, drag reduction, de-icing, electrochemical sensors and technology that uses graphene structures and electrical simulation to produce stem cells for nerve regeneration. The next step for the team will be to conduct more studies to better understand how the nano-and-microsurfaces of the printed graphene creates the water-repelling capabilities. 

Developmental status

We never know how a little carelessness on our own part – when we spilled coffee or some other liquid on any of our precious gadgets – will have us repenting on what we did unknowingly. A new generation of flexible circuit connectors could produce a new class of electronic applications, such as stretchable thermometers, biomedical devices and electronic clothing, all possessing the main advantage of being flexible and washable.

• Researchers from the University of Cambridge, working with colleagues in China and Italy have successfully integrated washable, breathable and stretchable electronic circuits into fabric, opening up many new possibilities for wearable electronics and smart textiles. The circuits have been made with safe, affordable, and environment friendly inks, and printed using conventional inkjet printing techniques.
• Researchers from the Japanese research institute RIKEN and the University of Tokyo have developed a new type of ultrathin, flexible organic solar cell, coated on both sides with elastomers to make it stretchable and waterproof. 
• Logitech, a Japanese firm claims to have developed the world's first waterproof smart phone that can be washed with soap and water. Logitech came up with the K310 washable keyboard which can be cleaned under the sink without worrying about it getting damaged or dysfunctional. However, these are not the only washable electronic equipments that can hit the sink defiantly. We’ve dozens of them already available in the market. Here we’ve listed some washable electronics which we can wash under the faucet with soap and water or wipe them clean.

Wireless Keyboard: Wetkeys washable wireless keyboard can be immersed in water and sanitized frequently. The perfectly waterproof, portable and flexible keyboard comes with its waterproof design offering maximum resistance to liquids.

Washable Mouse: The Belkin washable mouse is a water-resistant gadget that we can wash to keep clean or put directly under the tap. A strokeable, sensor-embedded strip acts as a track pad tool, which makes handling and controlling it a bit more difficult.

Washable illuminated pushbutton switch: Available in four LED colors, the TME 82 series washable, illuminated pushbutton switches from knitter-switch are designed for a wide variety of applications including office automation, games consoles, vending machines and measuring instruments.

Emano Tec MedTab: Developed by Emano Tec, the MedTab is a washable, pocket-sized tablet specially designed for use in healthcare industry. Since people involved in medical field know that germs are everywhere, it’s but necessary for them to have such sterilizable gadget at their workplace.