Polyester vs. Nylon Clothing for Hiking
One common complaint (or perhaps it’s not a complaint) among hikers is their clothing stinks. Even when the clothing has been properly laundered the stink is back within minutes of putting it back on your body. The reason is the chemical properties of the fabric.
I won’t go into a chemistry lesson, just a few bits of history and facts:
Nylon is the first synthetic fiber developed. The year was 1930, and it was more-or-less accidently discovered when Dr. Julian Hill – a research chemist – produced a gooey blob of material while studying the behavior of molecules and polymers. Although his research head deemed his discovery useless at first, Dr. Hill found he was able to draw out a long thin strand of material that remained flexible and soft and was remarkably strong. It became known as the 3-16 polyester super-silk fiber, the forerunner of nylon. DuPont – the company Dr. Hill worked for - soon patented the product, and by 1939 they had turned it into what we now know as nylon with the first nylon stockings on the market. It was hailed as a synthetic silk.
What does that mean for hiking?
Both nylon and polyester are most often made from crude oil, but have different properties regarding moisture and oil absorption. The biggest difference to the hiker is that polyester fabric is oleolphilic, or able to absorb oil and not water. It just so happens that body odors are oil based, binding to the polyester fabric and not letting go. After you launder your polyester shirt it may smell nice and clean, but once it warms up to body temperature being worn, that smell, well, there it is. You just cannot get the “hiker stank” to go away and stay gone! Nylon fabric on the other hand is NOT oleolphilic, so when you wash your clothing the smell goes away completely.
Polyester is also hydrophobic, meaning it will not absorb water. In comparison, Nylon absorbs a little bit of water, but only about 3 – 4%. So technically, polyester will handle moisture and dry faster since it is more hydrophobic than nylon. Also, water requires more heat energy to warm, so nylon feels colder when wet and stays wet longer. Although not much fun in winter, this could be a benefit in hot climates as the evaporation of the moisture in the fabric cools the body.
So what is wicking fabric, and how does that work?
Wicking is the transportation of fluid and is driven by temperature and humidity gradients. For example, if the climate inside your shirt is warmer and more humid than the outside air, moisture will be driven away from your body. This can also be accomplished by the construction of the fabric. Capillary action can pull fluids from one side of the material to the other with different thickness of threads in the garment.
But first, how is polyester and nylon thread made? In very basic terms, the liquid form is pushed through a spinner so that tiny strands or threads are pushed out. If the threads are stick straight, you would end up with flat smooth fabric. This wouldn’t be the most comfortable fabric to wear so they change the shape of the thread. They make the inside hollow, and give kinks and shapes to the outside to create a more cotton-y, softer feel. These shapes are also what helps moisture travel along the surface from one side of the garment to the other, aka wicking moisture. This works wonderfully if you are sitting around at home not exercising, or in a lab setting when they are testing the material under very controlled conditions.
So is wicking fabric good for hiking?
When out on the trail – hiking – you SWEAT. Sweat is not moisture vapor, it’s buckets of moisture. It does not make one bit of difference what material you’re wearing - it’s going to be soaked with sweat regardless. In other words, wicking properties will not keep up with the amount of moisture you’re producing. Now, one of the nice properties of polyester and nylon is that they both dry pretty fast, since we’ve learned they are both mostly hydrophobic.
Fabrics such as cotton, rayon, silk and wool love to hold onto water – they are hydrophilic. It’s for this reason they say “cotton kills”; Cotton doesn’t dry out quickly. Wool – which can absorb a lot of water – dries very slowly but has the amazing ability to keep you warm even when it’s wet. (SIDE NOTE: I can attest to this with first hand knowledge when I fell in a creek late one evening. The temperature was in the 40’s with a slight breeze and no sun. As long as I kept walking (and not even very fast or hard) I was warm. I was wearing wool long johns - top and bottom).
What are my personal preferences for hiking?
It depends on the environment! I prefer a long sleeve loose button down NYLON shirt if I’m going to be in open exposed (above tree line) areas. In hot, humid, shady areas, I’d rather wear a very lightweight wool t-shirt. (Wool will not hold onto the hiker stank either.)
What you wear is personal preference, and everything we’ve mentioned has their place and use – yes, even cotton t-shirts on hot summer days! They will get soaked with sweat, but the evaporation can cool you. I have called myself a “Fabric snob” in the past – I find textiles to be a fascinating subject – so I just wanted to educate you on what goes in to each individual fabric type to help make picking out your hiking outfits in the future even easier.