Polymer membranes are thin layers made from synthetic materials known as polymers. They are designed to selectively allow certain substances, like gases or liquids, to pass through while blocking others. This property makes them useful in various applications, including water purification, gas separation, and even in batteries. These membranes can be engineered to have specific characteristics, such as pore size and permeability, to meet the needs of different processes. Common types of polymers used in membrane production include polyethylene, polyvinylidene fluoride, and polysulfone. Their versatility and efficiency make polymer membranes an important technology in environmental and industrial fields.