How "wet" is "wet"?

The recent WIRED article regarding the confusion over indicator strips turning pink in humidity has me wondering what we mean by the term “water damage”. Am I putting my phone in danger from water damage when I use it in the bathroom to play the radio while I take a shower? Was it ultimately my own sweat that killed my MP3 player when I used to tuck it into my bra at the gym? And will my e-reader fall prey to the same faults if I keep using it in the kitchen, holding it in one hand whilst stirring the pot of steaming pasta with the other?

We learnt in the recent article, Why does a wet phone die? that electricity in the presence of water can cause electrochemical migration and permanent short circuiting of devices. But surely a bit of steam or sweat is a different matter, even if it is enough to turn an indicator strip pink? Another question for the gang in the P2i Labs, I think.

Can sweat and humidity really cause damage to electronic devices?

When P2i first emerged into the electronics sector, it was on hearing aid devices. These are very expensive, small, pieces of electronics that live behind the ear. A big issue in the hearing aid industry is corrosion damage, as the close proximity to the skin allows for the transferal of sweat and adds to the humidity and amount of moisture in the air around the device. This causes the metals inside the device to have a chemical reaction and begin to oxidize leading to the gradual degradation of the materials. P2i’s nano-coating dramatically reduces this corrosion damage and in just three years P2i went from coating zero to about 60% of the hearing devices produced globally.

How do you know what’s causing the damage?

One of the tests we did with the hearing devices, which we are also doing on smartphones, is known as an ‘accelerated corrosion test’. The idea is that over a period of days, we can mimic what a device is exposed to over its lifetime. The test allows us to introduce phases of increased salt or moisture, followed by dryer times, all the while increasing and decreasing the temperature; again mimicking the phases a device will go through in the real world. The aim of the test is to see how the materials in the phone will “weather” the conditions.

The video below shows the difference between a phone treated with the splash-proof (previously known as Aridion™) nano-coating, compared to an untreated device. The phones are going through the exact same test, and are periodically removed and photographed. 

What tends to happen is that as the temperature changes, water which may have entered the phone as innocent humidity, then condenses inside the phone, forming larger droplets. Now, not only do you have the oxidation of the metals, but you’re also in danger of electrochemical migration water damage, without ever getting your phone wet. 

Should I be worried?

Believe it or not, manufacturers are continuously looking for ways to make your phones more reliable. Motorola and Alcatel have already signed up to put the splash-proof coating on a range of devices before you buy them, so you don’t need to worry. We believe that as people continue to integrate the use of the mobile phone into every aspect of their life (including taking their phones in and out of humid conditions) then this trend from manufacturers will only increase. 

   

Why does a wet phone die?

I wouldn't say I am an accident prone person, but statistically I have destroyed a disproportionate number of phones due to water damage. One of the things that struck me, was how sometimes, if you’re quick at getting your phone out of the water and you turn it off, then pray to the phone Gods and keep your fingers crossed, sometimes, just sometimes, it magically comes back on again the next day…(at least until a week or two later when it starts acting ‘funny’).

In order to get a better understanding of what’s going on with a wet phone, I had a chat with the team in the P2i labs.

What happens when your phone gets wet?

There is a magnitude of possible outcomes when your phone gets wet. If you think about the number of entry points for water to get in the phone, then times that by the number of possible angles of entry, force of entry, droplet size (fully submerged, spray, mist, sweat) and type of liquid, you begin to see why the answer is not so black and white!

Perhaps one of the most obvious outcomes is that your phone ‘short circuits’ and powers out. If you think of a circuit board like a series of motorways, in the same way that we drive cars according to the direction and paths provided, the circuit board controls the flow of electrons, ensuring that your device works as specified. However when you add water to the mix, it’s like driving cross country or along sand dunes where there are no roads to act as a guide. As a conductor of electricity the water allows the electrons to flow freely.

With the liquid inside the phone allowing the electricity to flow in unintended directions, the essential voltage differences across the circuit board are interrupted, causing excessive electric current, heat and power outage.

Ok, so if I’m lucky enough to have my phone turn back on, why does it start going ‘funny’ after a couple of days/weeks?   

If you have ever opened a water damaged phone or piece of electronics you may have seen what looks like rust or a perhaps a white powdery substance. In the first instance the water or liquid is interacting with the metal causing a chemical reaction, as you would see with any metals exposed to the elements, like a tin roof. Except unlike the roof, the addition of energy supplied by the phone under power, accelerates the process. This causes degradation and wearing away of the metals inhibiting them from performing effectively. This is particularly evident in devices that are used in environments such as the gym or are kept close to the skin like headphones and hearing aids, where the addition of the salts in our sweat aid in the severity of the chemical reaction.

So what is it that makes a phone die altogether? 

Well this takes us back to the highway analogy. There is a type of corrosion called ‘electrochemical migration’. This is essentially the movement of metal ions from one point on a circuit board to another. This is able to occur because the water allows the free flow of electricity; so where once there were paths for the electricity to flow, allowing controlled differences in electrical charge between different points on the circuit, now  the water allows the metal ions to migrate. Eventually the metal ions will bridge the two points through the formation of a metal dendrite, acting as if a new road was created. Now, even when the water recedes, this new road permanently disrupts the control of electricity on the circuit board and the phone is no longer able to function as intended.

Do you have any advice for people who get their phones wet?  

It’s key to stop the electrical flow as soon as possible so first thing is to take the battery out. Then dry any excess visible water – worth noting that you should avoid trying to shake the water out as you may be inadvertently forcing it further into the device. Leave the phone to dry out completely before succumbing to the urge to test it…and unless it’s a Motorola or Alcatel device already treated with P2i’s tech, than feel free to keep your fingers crossed.