Shower caps are made from a variety of fabrics, but most are made from either rubber or vinyl. They can also be made from silicone, which is a synthetic rubber-like material that is not affected by heat or cold.Some shower caps are also treated with a waterproofing agent to make them water resistant. This type of fabric is usually a blend of cotton and polyester, or 100% polyester.When choosing a shower cap, it is important to consider the type of fabric that it is made from. If you are looking for one that is waterproof and resists moisture, then you should choose one made from silicone or a waterproof fabric blend. However, if you are looking for something that is more comfortable and breathable, then you should choose one made from rubber or vinyl.