Science of Fabric: Moisture Absorption Versus Moisture Wicking
Here are the facts:
Moisture absorptive fabrics typically are made up of hollow tubular fibres. They pull moisture directly into their inner core. They are great at absorbing moisture and like to hold onto it. Cotton, and Bamboo are classic examples of this. In fact bamboo has 4 times the absorptive capacity of cotton making it the ideal fabric for t-shirts after a sweaty ride.
Moisture wicking fabrics pull moisture along the spaces that exist between fibres. Unlike moisture absorptive fabrics, these fabrics are not as good at holding onto moisture. This helps to explain why they dry so quickly relative to both cotton and bamboo. Polyester is a classic example of this. If a moisture wicking jersey is engineered correctly water will spread quickly across from the inner to the outer surface where is it released to the external atmosphere in the form of water vapour (Figure 1a).
This process of evaporation dissipates heat away from the body keeping you cool.
So in summary, although both moisture absorptive and moisture wicking fabrics pull moisture away from the skin, they achieve this in different ways. How they achieve this dictates the usefulness of the fabric according to the needs of the athlete.
One final note, while polyester is chosen for its wicking capacity in helping to cool athletes during physical activity, Bamboo can also achieve this, but less effectively due its very nature of wanting to hold onto water within its fibres. This is sometimes termed the hydrophilic (water loving) effect of natural fibres versus the water hating (hydrophobic) effect of man made fabrics such as polyester.