Fresh water is running out. Technologies to make the beautiful briny potable will be essential in the coming years especially in the wake of climate change. Now, researchers from the USA have developed self-assembled block polymer membranes that could be both customizable and have uniform pore sizes for water treatment systems. "Most state-of-the-art membranes for water treatment are designed to let water pass through while filtering contaminants," explains team member William Phillip of the University of Notre Dame. Their tailored approach to block polymers allows them to choose precisely what materials are filtered which means they can process seawater, brackish water, and waste water in a way that is not readily available to conventional traditional technology.