UK coating innovation makes a splash for smartphones

Oxfordshire firm P2i has so far applied its hydrophobic nano-coating to over 175 million electronic devices worldwide. Jason Ford reports. 

It won’t have escaped your notice that smartphones are being marketed with features that have more to do with lifestyle than telephony.

Take the recent UK TV ad campaign for the Samsung Galaxy S7, which featured a young man anxious to receive a call from a young lady he’d exchanged telephone numbers with. The young lady eventually called him, but he fumbled with the phone and dropped it into the kitchen sink. Luckily, his Samsung Galaxy S7 continued ringing despite being immersed in a few inches of water.

coating on electronics
P2i’s coating protects devices inside and out

Similarly, Samsung’s ‘Quality Assurance’ advert depicts scientists at the company putting smartphones through a series of tests that include water being jetted horizontally at the screens of Samsung phones held at an angle.

It might not seem obvious but there are very good reasons for elevating waterproofing and water-repellent features up the USP rankings. According to IDC, the smartphone market has grown at an average rate of 33 per cent for a decade and the market is maturing. Consequently, handset manufacturers are looking more broadly at the features they offer in order to differentiate their products from those offered by competitors.

A YouGov survey conducted in the US in 2016 found that water resistance was the third most desirable feature of a smartphone behind longer battery life and shatterproof screens.

Enter P2i

Enter Oxfordshire firm, P2i, which has so far applied its hydrophobic nano-coating to over 175 million electronic devices worldwide and has won a 35 per cent market share in water-protected smartphones.

The story began at Durham University, where company chief technical officer Dr Stephen Coulson developed a plasma-coating technique that maintains breathability in military uniforms but repels liquids.

“This was project Crusader 21, which was the ultimate combat ensemble for the 21st-century soldier,” said Coulson. “The idea was to build in as much functionality into a soldier’s outfit without increasing the physiological load – the heat burden on the soldier. At the time, if you
think back to the late 1990s you’re looking at the end of the Cold War scenario and you’re taking equipment out of urban… environment[s] and putting them into hot desert areas. We were addressing the issues associated with asymmetric warfare.”

The coating process works like this: devices are loaded into the chamber of a machine where a vacuum is induced to hold the products at low pressure. A radio-frequency (RF) plasma then activates the device’s surface, which creates free-radical sites.

The monomer (a molecule that can be bonded to other identical molecules to form a polymer) is introduced as a vapour and a pulsed RF plasma is used to polymerise it and bond it to the free-radical sites on the surfaces.

untreated devices
Untreated devices are prone to water-induced corrosion

The low pressure in the chamber lets the monomer permeate into all areas of the device so that the polymer coats the internal and external surfaces and leaves an ultra-thin layer of polymer that is a few nanometres thick. The chamber is then vented back to room pressure and the coated items – which do not require post-processing – are removed.

Coulson explained that conventional coating technologies attach weakly to substrates.

“We’re growing it from the substrate, which gives it that chemical bond and because this is happening at the molecular level at low pressure, we’re confident it gets into all the nooks and crannies,” he said. The machines themselves are manufactured in the UK and are built to the requirements of P2i’s customers, who use the technology under license.

P2i holds 65 patents for its technology, which has so far been applied to filtration systems, performance and military clothing, electronic goods and life sciences applications. Its trademarks – Dunkable, ion-mask and Aridion – are applicable across these applications but the base technology is the same.

“The core patents take something that is very well known, which is liquid repellency and something that is very well known with regard to plasma deposition and combine the two to provide something very novel and inventive, which is the ability to retain [the] chemical structure at a surface using something that is known as a destructive technique, which is the plasmas. That was the inventive step,” said Coulson.

International footprint

P2i’s international footprint includes an applications centre in China and further offices in Taiwan and the US. The company’s clients include Huawei, Lenovo, Blackberry, TCL, Nokia, Plantronics and Motorola, which was the first handset manufacturer to use the invisible coating, applying it to the Droid Razr.

Dubbed Splash-proof, the coating protects against splashes, sprays, humidity and sweat, which qualifies it for an ingress protection (IP) rating of IPX2. The IP rating relates to how well equipment within an enclosure is protected against the ingress of dust and water, so a rating of IP67 would indicate that the device is totally dust tight (6) and protected against temporary immersion (7). According to Coulson, research carried out by IDC shows that Splash-proof technology protects against 42 per cent of liquid threats, but recent smartphone launches have seen an increase in standards that could work to P2i’s advantage.

The Samsung Galaxy S7 and S7 Edge have an IP rating of IP68, which means they’re water resistant to a maximum depth of 1.5m. Over at Apple, the iPhone 7 and iPhone 7 Plus have a rating of IP67.

“In order to get the rest of the threats covered as well then you need a technology to protect against accidental dunking underwater, hence the IPX7 criteria at the level that Sony, Apple and Samsung are now pitching the technology at,” said Coulson. “Therefore, that becomes a must-have technology in the industry and the ‘must-have’ performance level.”

The Galaxy S7 and S7 Edge are sealed mechanically, but P2i’s IPX7 level Dunkable – which is scheduled to launch in smartphones in 2018 – would afford the same level of protection to phones and electronic devices without the extra gaskets, membranes, snubbers, jack plugs and watertight casings. “We have a coating technology [that we] can roll out across the entire portfolio of manufacturers’ devices because we’re not limited to the huge costs and engineering constraints of a physical barrier,” said Coulson. “We’re identifying the partners we want to work with… and once we’ve collaborated with them and defined the timeline then we’ll be able to… launch this technology.”