The shortage of available fresh water is one of the global issues presently faced by humanity. To determine a solution to this problem, the survival strategies of plants have been examined. In this study, a nature-inspired membrane with a highly charged surface is proposed as an effective membrane for the filtration of saline water. To mimic the desalination characteristics of mangrove roots, a macroporous membrane based on polyethylene terephthalate is treated with polyelectrolytes using a layer-by-layer deposition method. As a result, most co-ions are repelled from the membrane surface, and counter-ions are also rejected by virtue of their electroneutrality. This nature-inspired membrane is applicable to the design of a small-scale, portable desalination device for use in third-world countries or small villages.