Fig. 1From: Transparent PAN:TiO2 and PAN-co-PMA:TiO2 Nanofiber Composite Membranes with High Efficiency in Particulate Matter Pollutants FiltrationMorphology of PAN:TiO2 and PAN-co-PMA:TiO2 nanofiber membrane composited with PP non-woven air filter (layers): optical photograph of nanofiber membranes of 2-layer (a) and 3-layer (c), and their enlarged top-views (c, d), respectivelyBack to article page