That depends on what you're looking for. Cotton is breathable and soft, but may wrinkle more easily. Polyester is made of synthetic fiber and is a high-tech nursing scrub fabric that resists stains and wrinkles, and does not shrink or stretch. This material might be less comfortable for some people. Spandex is a synthetic fiber that is more resistant to perspiration and stains. Rayon is made of regenerated cellulose fiber from wood pulp, and can be used to make scrubs that feel like silk, cotton, or wool. Some scrub brands use a blend of these materials to create a more durable and comfortable scrub.