There must be a learning process and we must be prepared to adapt to new scientific facts so that we can effectively combat the COVID-19 pandemic. Latest statistical data suggest that countries who implemented social distancing and obligatory masks for the public manage the COVID-19 pandemic with an accommodating increase of new patients. Medical masks due to insufficient supply must be reserved for medical and social personnel!
What it does
We are proposing a simple and cheap solution for the public. A comfortable design of cotton masks with a pocket for a replaceable nonwoven fabric filters. Filters are proposed by textile engineers at the Czech Technical University in Liberec (CTU in Liberec), i.e. nonwoven fabric filters. These nonwoven fabric filters decrease the penetrability of the virus by 85-90% (laboratory tests at the CTU in Liberec). They are meant to protect the people wearing these masks and to effectively reduce the virus spread in the environment, i.e. shops, inevitable social interactions, etc.
How we built it
The masks are made by sewing according to the proposed design. CTU in Liberec can make available the nonwoven fabrics with predefined dimensions. One cotton mask is estimated to last one month and one filter is estimated to last one day. Cotton masks can be disinfected with hot water and steam ironing.
General public can produce their cotton masks with a filter pocket according to the displayed design. Furthermore, a simple home made filter treated in a salt solution can be used as an efficient filter for these masks. The filter manufacturing process is proposed according to Doc. Ing. Stanislav Polzer from Czech Technical University in Ostrava (CTU in Ostrava) as follows:
Use some artificial fabric, such as nonwoven fabric for gardens, as a filter. The instructions are meant for a 15 x 20 cm filter. If the filter is smaller, the amount of solution must be reduced proportionally.
Prepare 300 g of salt and a large spoon of washing powder or dishwasher soap. N.B. The article in Nature Scientific Reports from Prof. Hyo-Jick Choi, University of Alberta recommends "Polysorbate 20 (common commercial brand names include Scattics, Alkest TW 20 and Tween 20), but probably nobody has it in the shelf at home. However, it is only a matter of reducing the surface tension of the water so that the solution can wrap all the fibers.
Pour a liter of hot water into a 1-liter measuring cup, add the washing powder and pour the salt over it. Mix it well to dissolve the salt (ideally all).
Soak the nonwoven fabric in 25 ml of the solution (i.e. put 5 teaspoons on a plate) and leave it soak overnight.
Place the same fabric in 55 ml of the solution (i.e. 11 teaspoons on a second plate) the next morning and put it in the oven at 40°C until all the liquid evaporates.
Put the treated nonwoven fabric in your cotton mask with a filter pocket and you have protection for all day long.
In the evening after coming home, throw the whole mask in a hot water for 30 minutes, then remove the filter from it and refill it with the brine solution. A liter of the prepared brine solution will last about 14 days.
If breathing through the tissue is very difficult, then the procedure can be performed with half the amount of solution. There will be less salt, but it still works. Unfortunately, there are no results for other concentrations or quantities.
This simple filter should both reduce the throughput of the virus and kill the virus on the filter surface. The filter dramatically reduces the risk of secondary transmission by touching the contaminated filter and then transferring the virus to another object. This protection also works in a humid environment and throughout the day, so there is no need to replace the mask with a new one.
N.B. The filter has not been tested against actual coronavirus, but there is a huge chance that it will work. The principle is physical - "High osmotic pressure destabilizes proteins".
Challenges we ran into
The design needs to be comfortable without seams in a nose area to avoid the increase of virus penetration possibility, easy adjustable to limit touching on the mask surface and cheap. Replaceable filters must be environmentally friendly.
Accomplishments that we're proud of
A comfortable design of a cotton mask by "Paul Brun" with a pocket for a nonwoven fabric filter. General public can produce their masks and efficient filters by themselves according to the proposed design and method.
Successful fashion proposal was accomplished.
What we learned
There is a network of designers, who can efficiently copy the comfortable design of a cotton mask with a special filter pocket. Mask dimensions are adapted to the effective area of filters. Masks are unisex and can be adapted to dimensions for kids as well.
The fashionable design of the cotton masks helps to motivate the general public by adopting them.
What's next for Designed cotton masks with replaceable filters for public
Promotional aspect (video) and an explanation in different languages, i.e. French, German, Italien, English.
Creation of the distribution network if needed.
Practical testing and material textile research.