Who would have thought that watching paint drops dry would be such a big deal? Well, we were wrong, as shown by a team of scientists at the University of Lyon who published a scientific paper on the subject. Their findings could change how colors are used by painters, as well as by ordinary people.
…And this wouldn’t be the first time
It’s actually not the first time someone has seen a dry drop; the “coffee Ring effect“After all that no It’s new In the scientific world, as well as in the world of coffee lovers. For those who don’t know, the so-called “coffee ring effect” occurs when… Wipe the coffee stain; You will notice that the edges of the stain are sharp Darker Compared to the center. This effect is due to the fact that the edges are tilted It evaporates more easilyThus the fluid in the center continues to transport molecules towards the edges.
Inspired by this phenomenon Stuart WilliamsMechanical Engineer At the University of Louisville in KentuckyHe was able to trace the movement of the liquid in some drops of it whiskeycame to a surprising conclusion: the special composition of alcohol prevented the creation of a real “coffee ring”, but rather a kind of “”Cobwebs“But the most surprising thing is that this effect occurs Only in American whisky, Not in their Scottish counterparts, that Different brands Of whiskey they brought to Different styles; As if they were some kind offingerprint“From the brand.
Which subsequently affects the drying patterns of the liquid It’s not just about what’s pendingin terms of powders or pigments, but also if they are present Special solventsSuch as alcohol in the case of whisky, or water in the case of colors and paints.
From whiskey to watercolor
In the technical fieldThere is no doubt that the problem is how the colors dry very importantthe Watercolor painters They have to deal withCoffee ring“; while those who use more complex colors such as advertising ones oil or AcrylicWhich consists of various components including Resins, Pigments, Extras And SolventsThe inevitable must be fought Cracks And Patterns that appear during drying.
A team of scientists led by Stella Ramos in the University to Leonin FranceTherefore, we set ourselves the goal of studying how different factors affect the drying process of colors suspended in water. The team focused on Two teachers Specific: Temperature of the substrate and concentration From the comment.
Use Team A Commercial acrylic paintWater-based and rich in resins, he then diluted it using five different concentrations High purity water; A few drops were dropped Hot slices At different temperatures, then left in environments with controlled temperature and humidity.
Ramos and his colleagues then used A CCD camera To record the process, and even a Electron microscope To examine the shape of the dried droplets, then measure their size Surface tension And the Color properties hanging; Coming to the conclusion that there is good Three mechanisms They compete with each other while drying the drop.
At first the liquid tends to… Move upin the cold region, but this movement is balanced Through poetic action which pushes outward; As time passes and the drop dries, it becomes more viscous, until it reaches 100°CGelatinAccording to the results of study A Lower concentration Of one color Low temperature leads to the creation of “Patterns Accurate hit on target“, while one Greater focus that it Temperature The higher the score is one Better color distributionThis is thanks to the gelatinization process.
According to the study’s authors, this experiment will lead to… Greater awareness Of the processes involved in drying colour; Awareness that would help to have greater control over this type of comment.
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