Scientists have developed ultrathin polymer membranes with a special structure featuring locked intrinsic microporosity. These membranes are designed for the separation and fractionation of hydrocarbons. The research was published in the journal Science in June 2026 in volume 392, issue 6804, on pages 1268-1273. Membranes with locked microporosity represent a new approach to chemical separation. This technology has potential applications in the petrochemical industry and hydrocarbon processing. The study demonstrates the possibility of using polymer materials with controlled structure to improve the efficiency of separation processes.