A natural fibre, woven cotton is lovely for summer as it is breathable and smooth. It is slightly absorbent, and can be prone to staining at times.
Simply a brushed version of woven cotton. After being brushed, the cotton fibres are a little more fluffy and softer. It still has the properties that come with being a natural fibre, but due to more surface area of the fibres, it's slightly more absorbent than woven cotton.
A plush, velvety feeling fabric. Fibres stand out from the fabric, and are held together by a mesh of polyester on the reverse side of the fabric. This is even more absorbent than flannel, and is cushier.
Think of your comfy t-shirt or undies, and you have cotton jersey. It's a smooth cotton knit fabric with some spandex for stretch. It has probably the equivalent absorbency to flannel and again, lovely in summer because there are no stand out fibres to trap heat.
Used for the bottom of some pads (especially those not PUL backed), corduroy has a grippy effect due to its ribbed nature. The fibres stand out from the fabric like velour does, however it does so in lines (ribs).
BAMBOO - Velour
Bamboo is 60% more absorbent than cotton, weight for weight, and more environmentally friendly to produce. It is just like cotton velour - lovely and plush ... BUT it's noticeably softer.
This is a non-natural fibre with a short pile - often used inside some cloth nappies as a stay dry layer. It's not quite as popular as the other fabrics, being not natural and not as luxurious feeling as Minky, for example - but it's a solid workhorse fabric that is strong, stain resistant and stay-dry feeling.
Like the wintery fabric, polar fleece, micro fleece is pretty much the same - but the pile is shorter and more fine. It's moisture resistant, so good for stay dry feeling on the top as it wicks the blood through onto the absorbent inner core of the pad. On the bottom of a pad, it's great for gripping onto your undies, and again as a moisture resistant layer. It's not waterproof, but blood would rather stay in the absorbent core than leak out through the micro fleece.
This is a long pile*, extravagant feeling non-natural fibre that you may have seen on the outside of cloth nappies. Very stroke-able - lovely on a cold winter's night. It's not really absorbent, and moisture will wick through onto the absorbent core. Most probably too hot to wear around in summer during the day.
*This minky pictured is a particularly long pile -they're not all that shaggy!
Highly absorbent, and usually 70% bamboo blended with 30% cotton, bamboo fleece has been the most common fabric used for absorbent reusable menstrual pads and cloth nappies. It is a stretch knit fabric with a fleecy and a smooth side, and really holds on to moisture. It can take a while to dry, which is why my pads with more than 2 layers of bamboo fleece in them have been designed to flip out so that they dry a little faster.
Hemp is a very sustainable and environmentally friendly fabric which is almost as absorbent as Bamboo. French Terry is smooth knit on one side and looped 'Terry towelling' on the other. Currently I am using this as the core in my Tiny pads.
I am about to commence production of pads using a Hemp fleece blended with Bamboo. Bamboo is more sustainable and environmentally friendly to grow than cotton... but Hemp surpasses them both. There is not much difference in absorbency between the latter two, but the common reason why Hemp is not used quite as much as bamboo is because it has a tendency to go a little crunchy and stiff after a few washes. It doesn't take much to 'rough up' the fabric to soften it again, though - and taking it off the line when it is 98% dry instead of 100% bone dry helps a lot. Putting it in the tumble dryer, even on cold, with a dryer ball or two is another idea.