The crocheted potholders that I have made consisted of two pieces that were sewn or crocheted together for double thickness. One side was the "decorative" side of the pattern, the other side was one color and the pattern for that was easier but matched the shape of the decorative side. I used cotton yarn and because they were of double thickness, they are fine to use. Some of the patterns were smaller though, so I used the larger patterns that I could find.
Also, Bernat has a pattern for a double thick oven mitt. Might be fun to try with the potholder as set.http://www.bernat.com/pattern.php?PID=2243
I made my potholders for gifts, and made matching dishcloths. No one I gave them to used a dishcloth nor knew what they were!