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I am experimenting to analyse the liquid wicking(radial) behaviour of various liquids. I have performed initial studies and experiments on household paper towels but they tend to deform and stick to the surface they are lying on, when wet, as shown below.

Liquid drop spreading on paper via wicking and wetting

I aim to find another paper with a high absorption speed. Wicking is apparent and produces an observable difference in speed and radius of wicking different liquids.

I am thinking of trying out with filter papers next as some similar studies have used filter papers.

Are there any other kinds of papers with a high absorption speed?

Also, if filter papers are a good choice, which grade or quality or any other attribute should I care to maximise absorption speed?

PS: I checked out chromatography paper also but they are costlier than filter papers. Unless the absorption speed difference is large I would rather use filter papers.

This happens on filter papers on the other hand for some liquids. The spread is minimal and a large drop of liquid just stays for a long time. enter image description here

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  • $\begingroup$ I think you've already posted this on another SE. $\endgroup$
    – DKNguyen
    Jun 2 at 19:15
  • $\begingroup$ do a google search not using paper but using "wood fiber." The paper type may matter to some degree - through-air-dried paper towels like Bounty will probably absorb faster just due to not crushing the fibers. But the determining factor will almost certainly be the type of wood. $\endgroup$
    – Tiger Guy
    Jun 2 at 19:42
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If you want to gage how wetable a liquid is, I would think, wetting angle (and possibly surface tension) measurement(s) would better differentiate between liquids. Low contact angles means more wetting. Capillary force was used to dial-in ink properties to optimize the Ball Point Pen's flow to the paper. Too high a force and the ink would skip and the meniscus at the ball would break. Too low and the ink blobbed.

I don't know if any paper product would exhibit equivalent adsorbent properties as fabricated from one day to the next, fiber distribution density, seasons of the year, season of fiber harvest or location of manufacture (as variables), might all have an effect. There is a nose tissue that is meant for kids with colds. It has "lotion" pre-applied. It is hydrophobic. You want hydrophilic. Any treatment applied to the media other than a wetting agent probably would degrade performance. You can probably create your own highly absobent media by taking your choice of product (filter paper maybe) and pre-treating it with wetting agents (or surfactants) like sodium lauryl sulfate, to increase absorption speed. Search on the terms above.

Also, any contact of the "paper" media and the support surface below, will create their own capillaries and adhesion of the paper to the support. I would say, place the paper over a hole in the support surface so it is just the paper product making contact with the liquid. Use a consistent drop size, consistent temperature of fluids and media, consistent test humidity and water fraction of the media, and maybe gage with an automated optical system (for wetted surface area maybe even area versus time).

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  • $\begingroup$ This is exactly what I want to do. Keeping the environment constant, using a consistent drop size I want to identify the water fraction of media based on the wetted surface area vs time behaviour. Paper towels and tissues transport liquids fast but wrinkle. Filter papers transport pure water fast enough but other liquids spread a little and a good amount of drop remains as it is for a very long time (refer pic in edited question). I will try wetting agent treatment. $\endgroup$
    – ashish.g
    Jun 3 at 6:00
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    $\begingroup$ In the bottom image is real results. The time it took to show as it is shown is data. Another one of your fluids might spred faster, and that too would be data. You are trying to find which fluid spreads faster, this is just one result. Now, if the same fluid on another piece of the same paper spread faster, then that too would be data. It may be that you will be averaging multiple measurements per fluid, for each fluid, and then gaging which fluid spreads faster. $\endgroup$
    – Jim Clark
    Jun 3 at 11:07
  • $\begingroup$ By keeping the water fraction of your media the same for all tests, I mean that perhaps you keep the media in a humidity controlled box before each test, so all the media has the same percent moisture before each test. You could set-up a box with a pre-wet humectant so the humidity inside remains constant. Give your media time to come to moisture fraction stability before each test. There are many different "salts" that control humdity to certain fractions. Omega.com has a paper about it. assets.omega.com/tech-ref-legacy-pdfs/z103.pdf will download a pdf of salt, humidity, and temp. $\endgroup$
    – Jim Clark
    Jun 3 at 11:15
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    $\begingroup$ Ultimately, you will have averages and standard deviations of your measurements. Use Student's T-Test to see if the results for your fluids are statistically different from each other to gage which fluid spreads faster. Try to keep all the variables constant for each test and you will be doing well. If you are at work let them know what you are doing and get advice from others: statisticians, engineers, your boss. $\endgroup$
    – Jim Clark
    Jun 4 at 10:47
  • $\begingroup$ I am following what you suggested, keeping other conditions similar, trying out filter paper and absorbent tissue roll with different water-based and oil-based solutions and colloids $\endgroup$
    – ashish.g
    Jun 5 at 5:59

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