hm, all the underwear I've been wearing is 100% cotton undies, and it's less like the pad getting stuck or not coming off, and more like the adhesive coming off the pad and then getting on the undies
but good to know anyway - thanks for sharing your experience!
I tend to dislike the texture of the synthetic fibers, so I tend to wear cotton as much as possible (it's a bit pricey, but I like to get my underwear from Pact).