Why does some clothes shrink when it gets wet?

Question

As for others it is ridiculously a joke but it's not. Why do you think some clothes shrink when it gets wet?

Any opinions are appreciated.

Answer 1

It depends of the weave. Cotton, canvas, denim and linen have a very tight weave, and when they become wet and heat dried, cotton fibers tend to tighten up and shrink. This is usually only during the first few washings, after which they won't shrink any more.

more about other fabrics and shrinking here:

http://www.answerbag.com/q_view/38969

Answer 2

wool and cellulose (as in cotton) both hydrogen bond to water.  I speculate that, depending on the shape of the fibre, this hydrogen bonding, possibly combined with surface tension, can bring the ends of small loops in the fibres closer together. In the worst-case, when the water evaporates, the fibre will either have stuck to itself through the interlacing of small rough patches, or hydrogen bonded to itself.

But this is just an opinion.