I previously asked a question about fabrics and by reading the answers I realized there is a lot of misinformation about the breathability of synthetic fabrics. ALL synthetics can be made extremely breathable. For example, nylon stockings are 100% synthetic and breathe well enough to be used as a face-covering disguise by bank robbers. Fishnet can also be made from 100% synthetic and it doesn't get any more breathable than that!
Conversely, a densely-woven cotton can have a very low breathability. If you've ever been in a canvas tent, you know exactly what I mean. 100% natural cotton canvas blocks airflow pretty much completely, even without waterproofing treatment. With all the flaps closed, the air in a canvas tent can get stuffy pretty fast. And when you consider how many yards of fabric you're surrounded by, even a tiny amount of breathability would allow enough airflow for the air to remain fresh.
What influences the breathability is not the fabric but the spaces between the threads which allow for air to flow from one side of the fabric to the other, which I believe may be called the tightness of the weave. Both synthetics and naturals can have a tight weave for low breathability or a loose weave for high breathability. I've worn 100% polyester slacks which were so breathable the slightest breeze went right through them, even though the material was pretty thick.
When it comes to ABSORPTION, that's a wholly different story. There's a good reason you never have a towel or washcloth made out of mostly or all synthetic: synthetics are plastics and plastic does not absorb water. This can mean that if you perspire you stay wetter much longer, leading you to think it is a breathability problem when it is an absorption issue.
On the other hand, synthetics can have excellent wicking ability, but that's different than absorption.
Personally, I prefer cotton and other naturals because they feel much better and absorb well. Synthetics seem sort of "cheap" to me, but that's just my feeling.
If I am wrong or missing information, please let me know.
Well, that's true about the openness of a weave (or a knit), but not the entire story. Since you're a man, you may never have worn those "breathable" nylon stockings on a hot day, and would not realize that, although air can pass through them, the stockings still hold enough heat to smother a girl on a hot day! Think of wearing plastic bags on your legs and lower half of the body, and you'll get the idea. Ugh.
Wool is an extremely complex fiber, and has not been duplicated by science. It can absorb humidity (up to 30% of its own weight without feeling wet), while at the same time repelling actual water droplets. The same weave, weight, and density of a wool fabric and a synthetic fabric have vastly different qualities. Cotton allows a similar pass-through of humidity, but it cannot absorb much water at all without feeling wet.
Even a small amount of a synthetic added to a natural fabric can affect breatheability, too. Someone who has a chemical or scientific background would have to give you an answer as to how much, since that's beyond my own scope of knowledge, other than the empirical knowledge gained by sewing with and wearing these fabrics for many years.
Karen Maslowski > I previously asked a question about fabrics and by reading the answers I
Synthetics can be either hydrophilic or hydrophobic. That means that some will absorb water and others will not.
They _can_ have better wicking ability and the ones that are sold for contact with skin or for insulation (like fleece) are almost always chosen to have good wicking properties.
The phrase "cotton kills" is common among outdoor enthusiasts because cotton is hydrophilic. It absorbs perspiration and is slow to dry. That means that once wet, you are at risk of hypothermia if the weather turns. Hence the preference for synthetics.
There are both good and bad synthetics. Even among just T shirts, there are those that feel like crap to wear (too rough or poor wicking) and those that are wonderfully comfortable. The latter tend to be a tad pricy - they're worth it.
Maybe its time for a "legs in" experiment! The only time I feel good in them at all is in the very coldest of saskatchewan winter, otherwise I start sweating like crazy. Even Fishnets wouldn't be so great because of the thick yarns used in them. And I wouldn't wear them unless it was halloween.
I think plastic bags would be more comfortable sometimes! I have to wear nylons alot because I love skirts, but work in a business-casual office.
"_may_ never have", ROFL! Well, maybe the next time it's 30 below I'll be wearing them for the extra warmth they provide, but UNDER my pants so nobody but me will know...
I don't doubt what you're saying, but I wonder how that works. I'm guessing that since they are worn skin-tight, they create an air buffer of millions of pockets of relatively still air even if there is a breeze blowing. In other words, air can flow through the mesh if there's air on both sides, but if there's air on once side and leg on the other, the air can't blow through because it has noplace to go. Also the fibers themselves probably have insulating properties.
That's interesting about woll and cotton, I did not know those things!
Well, Adam, we don't judge around here, and you just never know when a guy has been wearing whatever. :)
The nylon is hot because it's like a plastic. No matter how many "holes" it has, it's still plastered onto one's anatomy, and does not allow that much of the skin to breathe. It's hard to believe, but trust me, I know what I'm talking about here. I sold insurance for nine years and had to wear business attire at all times, even in the dog days of Ohio summer (very humid). And that meant nylons, so many was the August day I regretted my career choice when I had to go out to a very hot car in between appointments.
What you've read here is not misinformation; it's right out of the textile science reference books.
Many synthetic fibers are now as absorbent, some even more so, than natural fibers. It's fine for you to prefer natural fibers; in some cases, I do, too. But there are other cases where I prefer a blend. For example, if I buy a red t-shirt, I want it to stay that exact color. If there is some polyester in the blend, I know that it will stay that color, and not fade to pink, as it would if it were all cotton.
Linen is another fiber that is better mixed with something. I hate wrinkles, and linen is next to impossible to press at home. Blending it with rayon or polyester makes it much easier to press.
It is a plastic, but that's not why it's hot. I know this for several reasons but the mail one is because polyester is also a plastic, and a pair of knit polyester pants were the most breathable and coolest I've ever worn. The slightest breeze blew right through them. When I first wore them I wasn't used to feeling breezes on my legs, and I felt like I had to keep looking down to make sure they hadn't fallen off!
Breathability refers to the ability of a fabric to allow air to pass from one side to the other. Fabric is made of woven threads made from fibers. No fiber that any fabric is made of is breathable in itself; air cannot pass through a cotton, silk, linen or rayon _fiber_ any more than it can pass through a nylon, polyester or polypropylene one.
The only way ANY fabric can breathe is by spacing the fibers and threads far enough apart to let air flow between them. How well it breathes is determined by the size of the holes and to some extent the shape and depth of the holes and the "fuzziness" of the fiber or threads.
A fabric that is plastered to the skin cannot breathe at all in the normal sense of the word. Air can't pass from one side to the other because one side is blocked by skin, and the holes between the threads have now become pockets. (It's like opening only one window in your house, the breeze doesn't come in because it has no place to go.) Open a window on the other side and now you've got a breeze flowing through. Because of this, the air in the spaces between the threads can become "dead" or still air, which acts as an insulator. Perspiration cannot evaporate well because the air pockets quickly reach 100% humidity and no further evaporation occurs. With movement or wind there will be some refreshing of the air in the pockets but that can be quite limited by the size, shape and depth of the holes.
As I'm sure you know, most fabric is basically a mesh of tiny threads. The spaces in the mesh allow air to contact the skin or flow through the fabric. If the holes are small or nonexistent, the fabric will not breathe--it does not matter what the fabric is made of. Cotton can be made practically airtight. Early parachutes were made of canvas. The next material parachutes were made from was silk, another natural fabric. Parachute material must have extremely low breathability or the people using them tend to fall far too quickly.
Do you catch what I'm saying? I'm not disputing your assertion that nylons are hot. Please understand that I fully accept your valid experience with wearing them. All I am saying is that a material's breathability has little if anything to do with whether it is a synthetic or a natural fiber, and that nylons, while being hot, aren't hot because they are made of nylon as opposed to, say, cotton or silk.
You're wrong Adam. I hate to disappoint you, especially since you seem to think you've made a new discovery here to set the entire textile industry on its ear. But you have a lot to learn about textiles not the least of which is the complex properties of the fibers of which they are made. It's not strictly the spaces, Adam, because most clothing is made from fabric that does not have perceptible holes. It's mainly the properties of the specific fibers. If you view the html version of this chart (about 1/4 down the page), it will give you a reasonable overview of fiber properties and how you can expect those fibers to behave when worn on the body. Note that breathability is not especially technically relevant though the term is in common usage.
Breathability: Why isn't breathability technically relevant? Because, even if you make the spaces between the fibers visible, it is the fiber which contacts the body--- not the spaces. Fibers that are not absorbent do not permit moisture on the skin to evaporate into the fiber (and then evaporate into the air). Instead they hold the moisture next to the body and that is what makes them uncomfortable. Therefore, absorptive properties are more relevant, especially since most of us are not wearing "fishnet" clothing. Your notion that "all synthetics can be made extremely breathable" is simply irrelevant.
Densely woven cotton: Regardless of the weave, cotton is highly absorbent and so, consequently, is almost always comfortable except, perhaps when the humidity is 100%. Very few synthetics have decent wicking/absorptive properties (yes, Adam, it is the same property). But there are a few.
You would do well to respect the knowledge of most of the sewers who post here and who have taken their valuable time to advise you, some of whom are professional costumers and dressmakers. They've been at it a long time and know their craft well.
I hate to disappoint you, especially since you seem to think you've made a new discovery here to set the entire textile industry on its ear.
But you have a lot to learn about textiles...
It's not strictly the spaces, Adam, because...
Your notion that... is simply irrelevant.
You would do well to respect the knowledge of most of the sewers who post here and who have taken their valuable time to advise you...
Phaedrine, you forgot: "Now Adam, write on the blackboard 100 times: 'I'm sorry' and then go stand in the corner until you sweat"
Seriously, we probably all agree that clothing comfort (which started this thread) is a complex interplay among too many variables to allow easy answers, among them: cut and fit of garment, ambient temperature, R.H., wind velocity, permeability, wickability, absorption, adsorption characteristics of fibers and arrangement (weave), etc, etc. Personal preference trumps many of these due to skin sensitivity and personal preference. For eg, I find hemp/cotton t-shirts to be most comfortable to wear, although they are relatively coarse and stiff hand compared to my expensive jersey knit jobs and you wouldn't pick them in an A-B test in a store. Go figure.
Thanks for the informative textile references, Phaedrine.
Yet, my Polartec 100 snuggies don't absorb moisture at all. I understood Gore-Tex does not either. Am I wrong? Does Gore-Tex absorb water, and thusly moves it away from the skin?
I think you are confused between 'wicking' properties and absorbsion.
Gore Tex is not a fabric on its own; it's a membrain BONDED to a fabric that allows a wicking fabric to move water away from the skin side to the outside and does not allow it to come back - almost like a membrain of one-way valves.
Wicking fibres help to move moisture away from the skin to the outside of the fabric, where it can evaporate. Absorbent fabrics soak up the moisture and hold on to it. Evaporation rates from absorbent fabrics like cotton are far slower than from high tec poly wicking fabrics. This is one very good reason why light weight high tec wicking fabrics are far better for mountain and arctic uses than cottons, and a very good reason for dressing in something other than jeans for walking in the Caingorms. Treated and cleaned wool fabrics that are free from naturals oils are very absorbent. Wool that either still has the natural lanolin in the fibres or that has been re-treated with lanolin later ('oiled' wools) are naturally far more water resistant than cleaned wools, but still far more absorbent as fabrics than the high tec modern poly fabrics that so many mountaineers use.
Gore Tex layers are added to fabrics and clothing as a wind resistant layer as often as for the water 'proof' properties it gives garments, boots, and luggage. The modern fabrics are much better insulators as well as better for 'breathability' - their ability to let moisture out and keep the body inside warm and dry. A modern fleece such as Polartec Windbloc will allow body moisture out while keeping heat in, will dry more quickly after rain than a wool layer (though it is water resistant, it is not water proof and isn't designed to be used in place of a waterproof layer), and is far lighter than a wool layer with the same thermal insulation properties. Modern poly fibres of the right construction are also more breathable and insulate better than silk, a natural monofillament fibre with some very similar properties to polyester.
Don't let the term 'microfibre' confuse you either. Some cottons can be spun as finely as silk and poly fibres. 'Microfibre' is a purely descriptive term indicating the denier of the fibres used in the fabric.
One of the really good things about polyester fibres is that they don't crush when wet, like their natural counterparts. This is why so many modern sleeping bags are made of polyester fibres rather than down, or with a poly layer on the underside. If down gets damp (whether due to adverse weather/camp conditions or sweat) it clumps together and becomes far less of an insulator as well as drying out far more slowly than a similar tog rate of poly bag.
The Gore Tex membrane is expanded polytetrafluoroethylene - essentially Teflon that is stretched to make it porous. The holes are small enough that water vapour can pass through but liquid water cannot. Hence, insensible perspiration (i.e. that which evaporates directly off your skin) will pass through the membrane but liquid water on the outside (like rain) will not. Perspiration that is liquid (i.e. drops of sweat on your skin) cannot pass through the membrane either. Hence, it keeps you dry unless you are working so hard that you are sweating so much that the sweat beads on your skin.
The outer fabric to which the membrane is bonded has to remain dry for the breathing to work effectively. That is why it is coated with a DWR - durable water repellancy. That keeps the fabric hydrophobic. Wear and tear, dirt, oils and such will reduce the effectiveness of the DWR. For that reason, Gore Tex works best when kept clean. Heat tends to revive the DWR (dryer or iron), but once it's a tad old, you can use a product like Revive-X to restore the DWR.
Even if the fabric's dry, cold weather can make Gore Tex less breathable. Insensible perspiration can condense on the inside of the Gore Tex (and even freeze if conditions allow) before it can pass through the membrane.
It's great stuff, but a lot of people think that "breathable" = "no sweat". That's not the case and is why a lot of people complain about Gore Tex.
"Wicking fibres help to move moisture away from the skin to the outside
of the fabric, where it can evaporate. Absorbent fabrics soak up the moisture and hold on to it. Evaporation rates from absorbent fabrics like cotton are far slower than from high tec poly wicking fabrics."
say people, let's not get carried away here. cotton is a wicking fiber. it has been used since the 19th century as lamp wicks. cotton is not so good as an insulator _when it gets wet_. cotton soaks up a lot of water and water is not a good insulator. most of the synthetics under discussion her do not soak up much water. what they do do is hold the water on the outside of the fiber, and this water moves along the fiber coating the entire outside. the part of the fiber away from the body has lower relative humidity (usually) than the part of the fiber next to the body. (same same synthetic or cotton.) the water on the fiber in the lower relative humidity area evaporates. again, same same synthetic or cotton. the difference is cotton also holds water inside the fiber, and that water can not evaporate (inside the fiber) and it is not a good insulator.
Around here, lots of hunters wear pantyhose when they go out to sit all day in sub freezing weather. They swear they are better than anything else for keeping warm.
As for me, I have sworn off stockings of any kind. My skin reacts badly to synthetic fibers, and now that I am out of the workplace, I don't have to :-) I understand they are falling out of favor anyway, that it is becoming acceptable to go bare legged so long as one is shaved and tanned enough to be comfortable with that look. In winter, colored tights are okay in lieu of stockings/pantyhose. Of course, I guess this is a regional thing but I like it!
If I am then that's cool, I've learned something. But you haven't said anything to convince me yet.
ROFL!! I'm pretty sure that most if not all of the textile industry is well aware of these things, even though you may not be.
That is correct and I see no reason to deny it. However it makes no sense to me whatsoever that air can flow through a fiber. Air can flow *around* fibers, but not through them as they are composed of a solid, and air cannot flow through a solid.
Are you saying that air can flow through a fiber, rather than through the spaces around the fibers in the threads and materials? If so, can you provide any evidence for this?
The holes are perceptible under a microscope in many cases, but not all. However it does not matter whether you can see them or not, the fact is that there are spaces between the threads, or there is no breathing at all, unless we have a different meaning for the word breathable. Here is the one I am using, if you are using a different one please let me know so we can get on the same page:
Permitting air to pass through: POROUS; a breathable fabric.
As far as allowing air to pass through, "perceptible holes" are unnecessary. You don't have to be able to see holes in a fabric for them to be there. For example, I once had a wool coat that was more than 1/8th of an inch thick. I could hold the fabric to my lips and blow air through it with some fair amount of resistance, but could not see any light at all through the fabric. That is because the pathway the air molecules had to take from one side of the fabric to the other was extremely convoluted, not a straight tunnel. The air had to weave its way around many, many of the individual hairs of which wool is composed. Though the wool could breathe, the breathability was sharply reduced because of the fact that if air could quickly and easily pass through it, then the wind would blow through and make the person wearing it cold. But it was good that it had some ability to slowly pass air so that air humid with any perspiration could eventually pass through and there would be some venting going on.
We *must* be using a different definition for the word breathable. I am using the common one I found in a dictionary, but maybe the specialized terminology for describing the properties of fabrics (like the terminology for many specialized fields) is not listed in an ordinary dictionary.
If you view the html version of this
Wait, according to that page, the definition of breathable is "Breathable - a breathable fabric allows internal moisture (sweat) to escape through the fabric, allowing the skin to 'breathe' and remain comfortable. Air can pass in both directions, but moisture/water vapour will only pass outwards, as with our skin. "
That is incorrect, there is no fabric or membrane which will allow moisture or water to flow through in one direction, but I think what they mean is that it allows the air inside the garment, which has picked up moisture through evaporation, to flow through the fabric, carrying away moisture, while at the same time blocking the passage of liquid water. Since perspiration will often make the air inside the garment more humid, the net exchange of water molecules will be greater in the outward direction.
Fibers that are absorbent do absorb moisture which pulls it away from the skin, making the skin more comfortable, but they do not then necessarily allow the moisture to evaporate easily. Cotton in particular tends to be hydrophilic, which makes it great for absorption but it doesn't dry as fast as many synthetics. This can be a problem for people in cold climates who work up a good deal of perspiration and then sit or stand still for extended periods. Hence the hunter's phrase "Cotton kills."
Synthetics can have wicking ability. Wicking ability uses capillary action (the same thing which causes water to flow upward against gravity into paper, cloth and other fibrous things) which also pulls moisture away from the body, but also allows that moisture to evaporate off the fibers readily. (natural fibers have wicking ability as well to varying degrees.) Wicking ability does not feel the same as absorption and I suspect it does not do as good a job at removing moisture from the skin.
They can, depending on their properties, but they can also wick away moisture and that can make them comfortable.
For a small amount of perspiration, yes. For heavier amounts, simple absorption doesn't cut the mustard because it reaches a saturation point and becomes wet. The fabric has to readily give up its moisture to the air or (unless you are in a dry climate or a low-humidity weather pattern) it becomes wet and uncomfortable.
I consider that statement adequately refuted elsewhere in this post.
I know from direct experience that one summer when I was outdoors a lot, jeans were hot, sweaty and uncomfortable; the knit 100% polyester pants I tried were as cool as wearing nothing below the waist but a bathing suit, because the slightest breeze went right through... unless I was seated, in which case the airflow between my rear and the chair was blocked and I did feel damp... until I stood up and felt an instant cooling as the moisture evaporated. Note that my pants were not skin-tight in most places and therefore did allow for airflow. If they had been skin-tight like nylons, maybe they would have felt hot.
No, not exactly--but close.
As someone else posted, "Wicking fibres help to move moisture away from the skin to the outside of the fabric, where it can evaporate. Absorbent fabrics soak up the moisture and hold on to it. Evaporation rates from absorbent fabrics like cotton are far slower than from high tec poly wicking fabrics."
Or from the dictionary again, "wick" as a transitive verb: Main Entry: 2wick Function: transitive verb : to carry (as moisture) by capillary action -- often used with away
And Absorb:
2 a : to suck up or take up
Wicking carries something to another place, absorbing soaks it up. There is a fine distinction, but they are not the same.
Natural fibers can wick and absorb. Synthetic fibers can only wick, they cannot absorb (unless you consider Rayon a synthetic, I believe that cellulose can absorb.).
I see, this is one of those situations where we're dealing with the egos of "old-timers" who resent someone new coming in and not simply accepting everything they say as the gospel truth. Sorry, but while I do respect wisdom, I don't have an interest in pandering to sensitive and over-inflated egos especially when the folks who have them spew misinformation based on old wives' tales.
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