That’s a nice reference. Note that it talks about effusion (is the term I think) through a porous membrane (rubber). I don’t think it can be generalizable to modern envelope materials you would consider for a hydrogen or helium aerostat, as they should be impermeable to oxygen.
Clicking though links on Wikipedia got me to here:
Reference [2]:
Thanks for the two links. Both are related to endosmosis as defined by the links I provided, but in different areas ranging from biology (membrane) to Graham’s effusion law (also called Graham’s diffusion law), and relating phenomenons such as effusion, diffusion, permeation, endosmosis, exosmosis …
From Graham’s effusion law: “Therefore, hydrogen molecules effuse four times faster than those of oxygen.”
If there is no other factors preventing the following (such as the size of atoms or molecules), that implies that air enters in a helium or hydrogen aerostat (in a lesser proportion than the helium or hydrogen leaking) and confirms the old experiments and the recent observations from Dave Santos and some other.
All the papers and indications about gas balloons and airships mention leaks. And leaks occurring should imply that some air enters in the aerostat, apart perhaps some possible factor I mentioned above. Modern envelope materials mitigate leaks, so they mitigate also the entering of air, but without cancelling them as perfectly as a hydrogen-tight metal tank would do. However perhaps some modern envelope material would not be air-tight to hydrogen (leaking) while being air-tight to air (not entering), or air-tight to both: it is a point to check.
https://www.researchgate.net/publication/259504329_Graphene_An_impermeable_or_selectively_permeable_membrane_for_atomic_species
As the air-hydrogen mixture is explosive, the effusion concern is very important if we want to try to make hydrogen safer for aerostats that are used for a long time.
That person would seem to be the one to ask.
My first questions for this topic would be, where could you buy a helium balloon, how expensive is it, how expensive would it be to fill it with carbon-neutral hydrogen, and how much hydrogen or helium would it lose over time?
But to continue this exploration of diffusion through a membrane, maybe this is relevant:
07979_intro1-5.pdf (301.5 KB) [Plastics Design Library] Liesl K. Massey - Permeability properties of plastics and elastomers (2003, William Andrew).rar (2.4 MB)
07979_thermopl1-15.pdf (453.2 KB) 07979_thermopl16-32.pdf (391.1 KB) 07979_thermopl33-46.pdf (460.4 KB) 07979_thermopl47-60.pdf (393.2 KB)
If Windy Skies would experiment with balloon envelope materials, the following effects would be easily observed-
-Overly heavy material may hold gas well enough, but the excess mass is highly parasitic to lift performance.
-Thin-film high performance gas-retention materials suffer from rapid degradation in practical use.
There is a mysterious aspect to rapid loss of gas-tight performance. My old theory in the LTA field proposed that static electricity (corona discharge) punches microscopic holes. Quantum tunneling of molecules is a related analytic prediction.
This is perhaps the most thorough discussion on permeation I have been able to find:
This is probably the most helpful resource on permeation I have been able to find:
The source provided further substantiates the well-established LTA gas leakage problem.
Fortunately, AWE need not depend on LTA gas, with all the hidden engineering shortcomings in cost, complexity, and performance.
https://www.reddit.com/user/GrafZeppelin127, like the username suggests, comments on things like this often.
https://www.reddit.com/r/solarpunk/comments/1g1n72f/this_is_what_i_picture_when_i_imagine_solarpunk/
https://www.reddit.com/r/aviation/comments/1fzww9f/today_i_saw_a_blimp_on_the_ground_and_take_off/
Some related talk: Preprint: Towards a gigantic Magnus balloon with motorized belts - #158 by Windy_Skies
Robotic “spiders” repair holes in hybrid airships.
The Lockheed Martin Skunkworks is famous for creating spy planes like the SR71 Blackbird. The Skunkworks engineers are now working on a new kind of airship. And they have also designed a novel solution for repairing the skin of their airship, robots.
More information on:
And also (in French):
Interesting note on:
Et de toutes façons, les fuites ne sont pas un gros souci: le Vectran est très résistant, et si une fuite se produit, l’hélium étant stocké dans l’enveloppe à très basse pression, la seule pression de l’air ambiant suffit à le maintenir dans le dirigeable, en attendant l’arrivée du Spider.
Translation:
And in any case, leaks are not a big problem: Vectran is very resistant, and if a leak occurs, the helium being stored in the envelope at very low pressure, the only pressure of the ambient air is enough to keep him in the airship, waiting for the Spider to arrive.
That I said I am not sure if “robotic spiders” would be a solution for an aerostat inflated with hydrogen. They could perhaps (hypothetically) cause static electricity by friction on the skin of the aerostat, and hydrogen is very flammable:
Hugo Eckener argued that the fire was started by an electric spark which was caused by a buildup of static electricity on the airship.[42] The spark ignited hydrogen on the outer skin.
Love the robot spider patching device…
Years ago I had in mind a way to accurately coordinate the position of 2 sides of a sewing machine like this to enable attachment within volumes in sequences otherwise impossible.
I guess this spider could also be adapted to weld strips / web lines between inner surface parts … like a mini shape wave device?
Hydrogen balloon transportation: A cheap and efficient mode to transport hydrogen - ScienceDirect
Highlights
A new approach to transporting hydrogen with balloons.
Possible paths for hydrogen balloon transportation.
Estimation of the optimum altitude to transport hydrogen in balloons.
The global potential for hydrogen balloon transportation is accessed.
Fig. 1. Hydrogen balloon transportation (HBT) description.
Fig. 2. The hydrogen balloon (a) can be transported by a support ship to the H2 network (b) can be lowered by the support ship, (c) can reduce fuel consumption of passing ships and (d) can generate electricity with tidal power in the support ship.
2. Hydrogen balloon transportation (HBT)
[…]To increase the safety of this transportation mode, hydrogen balloons should only fly over the ocean. This is convenient because support ships could assist in the transportation of the balloons in any direction on the ocean. This would not be possible on the continent. If the weather forecast is wrong and the balloon is blown away from the path to its destination and ends up flying over the continent, the balloon could be guided to land to minimize the risks of incidents.[…]
Can we deduce that under certain conditions hydrogen could be used or/and produced for some AWES?
Would there be a way to combine these two industries: Hydrogen Balloon Transportation (HBT) and Airborne Wind Energy (AWE)?
Hi Pierre: This is actually a version of an old idea of mine.
Anyway, we should not forget that hydrogen is, by far, the least efficient method of energy storage commonly discussed. Ironically, the people discussing hydrogen seem largely unaware that it even IS just a method of energy storage. They tend to think of hydrogen as simply “a fuel” that could replace hydrocarbon fuels. But unless hydrocarbons are used to make the hydrogen, it is just a far less efficient way to store wind or solar energy than batteries, or even compressed air.
The problem is, as usual, the “derangement syndrome”, where clear and complete thinking is abandoned in favor of bumper-sticker-level, slogan-based “reasoning” that is, in fact, not reasoning at all, any more than hydrogen is “just another fuel”.
Of course at some point, even the most indoctrinated Kool-Aid drinkers had to recognize that the hydrogen had to come from somewhere, and that storing solar or wind power at a 10% efficiency was just wasteful nonsense, so they had to come up with a new “cover story”. That cover story is that there “may be” (possibly) large amounts of hydrogen underground, ready to be easily extracted by drilling! (Professor Crackpot strikes again?) Only thing is, after a century of intensive drilling and exploration for oil, gas, water, and minerals, the existence of easily extractable hydrogen in large amounts would already be known, not just a speculative and soon-to-be-forgotten “news” story.
Hi Doug,
This is not the storage I was looking at in the first place.
Rather, it is the indications that would be useful for AWE.
And this paper indicates something interesting, in that hydrogen (which is much more widespread and cheaper than helium) would be little dangerous for unmanned balloons without moving parts, and flying above sea.
2. Hydrogen balloon transportation (HBT)
[…]
To reduce the risk of explosion, hydrogen balloons should not have propellers or other moving parts. Following these proposals, the risk of incidents with hydrogen transportation is insignificant.
In the conclusion:
We propose HBT be considered only over the ocean.
So I wrote a comment with a sketch for a balloon without moving parts to avoid frictions close to the envelope. In a similar way a Magnus balloon driven by external belts would not be suitable.
For AWES including a hydrogen-inflated aerostat, we can imagine a coupling of AWE industries with industries using and producing hydrogen, so that during the forecasting of storms or storms, the balloon is deflated and the recovered hydrogen is used in the industry concerned, the balloon being inflated again by the hydrogen produced in the said industry.
For the hydrogen industries concerned including by-products (see the link below), AWES aerostats would also be temporary storage facilities that could eventually and advantageously replace some other temporary storages by avoiding compression and decompression losses.
Yes, “we can imagine”… 
The storage method as described in this publication could remove the need for compression in heavy containers and therefore the doubled losses.
In addition, the hydrogen-filled blimp without moving parts could perhaps be a way to lift a wind turbine by mitigating the risk, as sketched below.
Indeed this publication precises, page 877 (just before “3. Methodology”), quoted again:
But the publication is about giant flexible balloons of 0.52 km³ (at the surface, table 3) or 1 km³ (at 6 km altitude, table 3), leading to a very large hoop stress issue preventing large scaling up:
