Fig. 4: The cross-section images of porous polymer film and non-porous polymer film.
From: Humidity-tolerant porous polymer coating for passive daytime radiative cooling
a, b Cross-sectional scanning electron microscope (SEM) images of porous polymer coating (PPC) and fumed silica added porous polymer coating (FSPPC). c A high magnification SEM image showing well embedded fumed silica inside the pore wall. Inset shows the transmission electron microscope (TEM) image of individual fumed silica. d, e Cross-sectional SEM images of non-porous polymer matrix (PC) and fumed silica added non-porous polymer matrix (FSPC), which is a non-porous coating fabricated without the addition of a nonsolvent. f Low magnification cross-sectional SEM image of FSPC showing the non-porous, dense morphology through the entire film thickness.
