Does water diffuse trough rubber of car tire of when liquid or only as gas Does Water difuse trough rubber of car tire when its liquid or only when its a gas.
Can also be that is diffuses but slower when liqiud.
I want to know this for my argumentation that filling car tire with normal air with water in it, is better then filling with Nitrogen.
so if you also know what the diffusion speed is of water as gas in compare to Nitrogen, I also would like to know. So for instance 5 times as fast as Nitrogen.
From Oxigen I already learned it to be 3 to 5 times as fast as Nitrogen.
But this not mean that if pure Nitrogen tires filling that the pressure is after a time 10% lower that 100% oxigen filled tire in that same time looses 30 to 50 %.
 A: Diffusion is the process where particles will tend to redistribute to equalize their concentration through random motion.
The key here is the random motion. The random motion of particles could be for example ping pong balls bouncing around in a violently shaking container, or the random motion of particles due to thermal energy.
In the case of liquid water, if the particles were droplets, with many molecules, when they collided, instead of bouncing, they would join together becoming bigger particles. This process would not spontaneously reverse itself because of surface tension.
Thus in order for water to exhibit diffusion, the particles must be molecular. Now diffusion only presents itself when there is a concentration gradient. The concentration can be measured as number of particles per volume$^1$. In pure liquid water this remains nearly constant as it is just proportional to density. Thus, it's not really possible to have diffusion in pure liquid water.
This doesn't necessarily mean that liquid water can't escape the tire though. If there is a small channel, it may be possible for liquid water to flow (as opposed to diffuse) through the channel. In a flow, the motion is not dominated by random motion but rather is a bulk movement that depends on total pressure gradients rather than partial pressure gradients.
In this case, I don't believe there would be a flow because at some point there would be an interface of liquid water to a gas.  At that interface there would be a pressure jump due to surface tension. I believe this pressure jump would be able to overcome the pressure difference between the inside and outside of the tire. However, to validate this theory it would require knowing, the surface tension of water ($70 \frac{mN}{m}$), the contact angle at a water, tire-rubber, air interface (?), and the narrowest cross section of the channels through the tire wall (?).
Side note regarding comment by OP on the question: Due to the ideal gas law, pressure already increases with temperature and this is what forces people to fill their tires in fall (and let pressure out if it doesn't leak out fast enough in the spring) adding water intentionally would only exacerbate the issue.
