AbstractThis paper studies the effects of five parameters, including fiber diameter, crystallinity, thickness, packing density, and surface roughness, on the transparency of electrospun polymethyl methacrylate/polydimethylsiloxane (PMMA/PDMS) nanofibrous membranes after heat treatment. The PMMA/PDMS membranes produced at an electrospinning voltage of 20 kV reaches 54.85% transparency with the diameter 0.759 μm, crystallinity 14.81%, thickness 9.2 μm, roughness 0.659 μm, and packing density α 0.0081% after the heat treatment from 80 to 200°C. In general, the PMMA/PDMS membranes present higher transparency with the decrease of diameter, crystallinity, thickness, roughness, and packing density. The influencing parameters on transparency are first quantified by multiple nonlinear regressions with a R2 of the model equals 0.869. A composite scaled sensitivity (CSSj) analysis shows that the most influential factor is the nanofibrous membrane thickness with a CSSj value of 1, followed by fiber diameter with a CSSj value of 0.515. The CSSj values for packing density, membrane roughness and crystallinity are 0.385, 0.361, and 0.173, respectively. Finally, the nanofibrous membrane transparency is a function of nanofiber material density, fiber diameter, and nanofibrous membrane thickness based on the Chandrasekhar radiative transfer equation and the Rayleigh's Scattering Theory.