WHAT ARE THE BEST FABRIC MATERIALS FOR CLOTH MASKS?
For the past month, I have felt like I am racing against time to determine the best possible materials for making masks for the 2020 Covid-19 pandemic. The CDC's somewhat vague recommendations to wear a bandana or scarf when you have nothing else, coupled with the World Health Organization's (WHO) recommendation for everyone to wear masks while in public is frankly terrifying to both those in and outside of the medical community. Did I ever think healthcare professionals would be forced to use the same mask throughout their whole shift in our cushy first-world country? No. Did I ever think that I would be spending the majority of my day frantically DIY'ing face masks for everyone I know out of fabric, embroidery stabilizer, and a pipe cleaner like a modern-day MacGuyver? Absolutely not. But that is the reality that we are faced with at this point in time and there really are no other options other than do what we can and hope for the best.
Because I have an extensive background in microscopy (I even coauthored a book!), am a nurse by trade (though off-duty at the moment to raise my family), an avid sewer, and an all-around nerd I was inspired to try my own little science experiment, using things that are readily accessible to the public.
Enter the USB microscope. It is cheap, easily accessible, has free 2-day shipping (thanks, Amazon!) and can help users make a visual determination in what fabrics might and might not allow stray particulates through by allowing them to see how much light passes through the microscopic holes in an average sample of fabric. This is clearly not as good of a microscope as I have used in the past but it does the job as well as it possibly can. Clearly, if you have access to fancy equipment by all means! test away! But until then I have to rely on materials that I have at home to make the best judgment that I can so that I feel safe with the material that will hopefully prevent me from passing on (and hopefully catching as well) a virus.
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| $20 USB microscope |
I wish I had a single color of each fabric tested, but sadly, because I cannot go to the store right now I have to use what I have at home, which is somewhat varied. However, I tried to choose fabrics that are neither white nor black but somewhere in between in order to more clearly show the fibers. For most of the filter material, because the fabrics were white or mostly-white, I chose black cardstock with the fabrics lit by the microscope itself. For dark-colored fabrics, it was easier to visualize by using a white lit background. Therefore, I selected my Cricut (TM) BrightPad to really make the fibers stand out.
Because the general population is now being encouraged to wear a mask while in public I decided to use a variety of commonly-available fabrics that I have seen masks being made from, as well as a selection of filter material (available in the next post!)- both readily-accessible to the public and those that are strictly for healthcare institutions. I believe that this might help those that do not have access to medical-grade materials decide for themselves which materials would make a good substitute. Also, because the CDC is recommending healthcare providers wear a bandana and scarf if there is nothing else, I wanted to include those as well. Because, science!
Below you will find the results. I used the same magnification (the microscope claims to be 50x and 1000x and I chose 50x to be able to see more of the fibers) and ambient lighting. The camera automatically adjusts white balance (something I cannot turn off), so sometimes the lit background appears overexposed if it is covered with a mostly-dark fabric. I took images of both a single layer and a double layer of the fabric, to get an idea how much light would be blocked by the fabric itself and your average 2-layer mask. I will write my impressions last, but I want to present the images first so that you can be your own judge. I also need to state that these opinions are my own and absolutely do not constitute medical advice, so use this visual data as a reference to make your own decisions. Here goes!
FABRICS (50x magnification):
Single-Layer
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| Bandana (100% cotton) |
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| Cotton Batik |
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| Cotton flannel |
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| Broadcloth (35% cotton, 65% polyester) |
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| Double-brushed polyester knit (unstretched) |
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| Duck fabric |
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| Fleece |
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| Outdoor (UV-treated) fabric |
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| Scarf |
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| 100% Cotton |
Double-Layer
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| Bandana (100% cotton) |
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Batik (100% cotton)
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| Broadcloth (35% cotton, 65% polyester) |
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| Double-brushed polyester knit (unstretched) |
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| Double-brushed polyester (stretched) |
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| Duck fabric |
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| Fleece |
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| Outdoor fabric |
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| Scarf |
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Cotton flannel
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ANALYSIS OF FABRICS:
100% Cotton:
- PROS:
- Holes appear small, however they do not appear to be as small as some of the other samples.
- Breathability is decent- one could wear a mask with 2-3 layers comfortably
- Easy to find, cheap, and available in a wide selection of colors and patterns
- Can be washed on high heat
- CONS:
- Not considered an antimicrobial fabric- thus, if it is exposed to moisture and heat for a prolonged amount of time it has the potential for bacterial growth.
- Shrinks after washing, wrinkles easily, and can be uncomfortable on skin
Broadcloth (35% cotton, 65% polyester)
- PROS:
- Holes appear small and rectangular-shaped, potentially blocking particles that have a diameter larger than the shortest edge
- Does not wrinkle as easily, feels soft on the skin, and is affordable
- Because it contains a synthetic material, the fabric could be argued to more antimicrobial than 100% cotton
- CONS:
- Slightly less breathable than 100% cotton
- Available in a limited selection of colors, some stores do not carry blends so it is not as accessible as cotton
Flannel
- PROS:
- Holes are not uniform in size but the largest hole appears to be smaller than both the cotton and cotton/poly blend
- Inexpensive and comes in a wide range of colors and patterns
- Feels soft
- CONS:
- Warm against the skin- wearing 1 layer of flannel would not offer enough protection, yet any more than 2 layers would be uncomfortable.
Fleece
- PROS:
- Synthetic fabric, so potentially resistant to growth
- Inexpensive, easy to find, and soft
- Appears to block light very well, with only very small holes present
- CONS:
- VERY warm against the skin- while using 2 layers appeared to block out all light it would be extremely uncomfortable for an individual to wear this over their mouth.
- Thick fabric- could potentially limit pleating due to bulk
Bandana
- PROS:
- Easy to find in many commercial stores, inexpensive, and already cut to size
- Can be washed on high heat
- Most people can tie a bandana around their face without having to use a tailor for a custom fit
- CONS:
- Holes appear much larger than 100% cotton found in fabric stores
- Natural material, which means there is the potential for microbial growth with prolonged wear
Scarf
- PROS:
- 100% synthetic material, so potentially resistant to growth
- CONS:
- Holes appear extremely large in comparison to the other fabric choices
Duck
- PROS:
- Holes appear rectangular in shape, potentially limiting particles with diameters greater than the shortest side from passing through. The fibers also appear to have smaller fibers that are tangled inside the holes, which may also act as a barrier
- Rugged material that can be found at most fabric stores, fairly inexpensive
- CONS:
- Although the shortest side of the holes appear to be roughly the same size as the cotton, the longest side is several times the length.
- Thicker fabric that is more difficult to breath through compared to cotton
- Natural material- which means a potential for microbial growth
Outdoor fabric
- PROS:
- Rectangular holes in which the shortest side is roughly the same size as the cotton fabric
- Treated for outdoor use, so potentially resistant to splashes
- CONS:
- Expensive compared to cotton, and is not as easily found in large stores
- Not the smallest holes out of the fabrics sampled
Double-brushed polyester knit
- PROS:
- When in unstretched state, holes appear very small.
- Soft on the skin, and breathable
- CONS:
- Expensive compared to cotton
- When stretched, numerous large holes appear
FINAL IMPRESSIONS ON FABRICS:
Who is the winner in my opinion?:
First Place: Cotton batik
Second Place: Cotton/polyester blend
Third Place: 100% Cotton fabric
Overall, the cotton fabrics (100% cotton, batik, and cotton/poly blend) kind of have it all. They are breathable, can be found in many stores, are inexpensive, and appear to have uniformly small holes. The batik is overall more expensive, but the holes appear closer together so one can assume more particles can be blocked. I love that batik is naturally resistant to droplets due to the wax used in creating the beautiful patterns, but this could potentially fade with high heat use. I like cotton/poly because it is more resistant to growth and is soft, but not many stores carry a good selection. And 100% cotton can be found even in big-box stores. And all three of these can be washed on high heat if needed.
While the flannel and fleece I felt blocked out quite a bit of light, they are quite warm against the skin and would make breathing uncomfortable, potentially forcing the wearer to remove the mask which would then expose them to any airborne particles. I would, however, potentially add flannel as an inner layer along with a cotton as I think one layer wouldn't be too much of a nuisance for the average wearer.
The bandana I thought performed poorly. Although it can be bought in big-box stores, the better-quality 100% cotton fabric appeared to block more light- and it can be found just as easily- if not more easily- than bandanas.
The scarf- No, just no.
I wasn't really impressed with the duck or outdoor fabric. It isn't as easily found as cottons, is typically more expensive, and doesn't really appear to offer any other benefit.
The knit fabric appeared to block out quite a bit of light, but I would still stay away from it because the holes increased in size depending on stretch, and it would be next to impossible to keep a knit from stretching. Plus, it is generally much more expensive than cotton.
Finally, while 2 layers seemed to block out quite a bit of light I believe it is STILL not efficient at blocking smaller particles, and most definitely not viruses, which are extremely tiny. Therefore, in addition to a minimum of 2 layers of fabric I believe a filter is needed, either sewn into the mask itself or placed in a pocket as a disposable insert. To view my post on filter fabrics, click here.
I hope you enjoyed this little experiment on fabrics. Thank you for reading, and keep safe!
