Nothing spoils the looks of a shower curtain liner more than mildew spots. Mildew is among the many molds that will find a home on any damp surface.
It is important to note that the words "mildew resistant" do not indicate that a curtain liner or any other product is "mildew proof." Any material that remains damp for a significant amount of time is subject to the growth of mildew. Mildew spores are in the air all the time, so it is inevitable that they will make contact and settle on a mildew resistant curtain.
Hotel Style Curtains
Hotel style curtains are often recommended for the home. These curtains are generally much heavier than domestic shower curtains. Hotel style curtains are not necessarily more mildew resistant. Hotels have strict housekeeping rules, which means that their curtains are cleaned and bleached on a regular basis.
PVC and Plastics
Vinyl curtains and plastic curtains are said to be mildew resistant. The resistance is created initially by the lack of nutritional value in the material, making it a hostile environment for mold spores. As the curtain is used, it will gradually accumulate surface film. This film can make a fertile ground for the mildew to grow in.
There are 2 materials that can claim to be mildew proof, to a degree. They are hemp and bamboo. Both can be used to produce a fine fiber that can be tightly woven to be used as a shower curtain or simply as a liner. The natural resistance to mildew in the fibers does last a long time, but when the curtains have been washed a few times, it becomes less effective.
Mildew resistance can be enhanced if simple precautions are taken to prevent the creation of areas of dampness. When choosing a shower curtain liner, find a curtain with a smooth finish. Hanging the smooth side of the curtain inside the shower will reduce the chances of the water staying on the curtain.
After using the shower, leave the curtain partially open to allow air to circulate and remove the damp atmosphere faster. By being partially open you will also leave the curtain with no two sides of a fold being in contact with each other. Where 2 sides of a fold are in contact, the water is held in place rather than draining.
Wiping the shower curtain liner with a damp towel will reduce the amount of moisture still clinging to the curtain; it will evaporate much more quickly. It will also remove any film that might be building up from the use of shampoo, soap, and hair conditioner.
At least once a week, sponge the shower curtain with a mild bleach or disinfectant solution to kill any spores that might have settled. Starting with a mildew resistant shower curtain lining is a good first step for preventing mildew. Any shower curtain that is dry soon after the shower has been used will probably not suffer from mildew.