In this work, a unique vapor crosslinking method is applied for the first time to fabricate polyimide-based pervaporation membranes for the dehydration of acetone. By controlling the temperature and duration of the crosslinking reaction using ethylenediamine (EDA) vapor and using the right dope formulation to cast P84 co-polyimide membranes with balanced macrovoid and sponge-like morphology, we have optimized the crosslinking parameters to obtain a membrane with a separation factor of 53 (i.e., a water permeate concentration of 90%) and a high flux of 1.8 kg m(-2) h(-1) for pervaporation dehydration of acetone at 50 degrees C from a feed of 85/15 acetone/water. With the aid of characterizations for surface chemistry and physics of the modified membranes, such as FTIR-ATR, XPS, and XRD, the crosslinking between EDA and P84 is confirmed at the selective layer of the membrane, as well as structure-performance relationship. This new modification method for pervaporation membranes is attractive for creating a new class of membranes for the separation of organic solvents and biofuel. (C) 2014 Elsevier B.V. All rights reserved