A support film of plasma-polymerized naphthalene for electron microscopy: method of preparation and application

Methods of preparing of a new support film by plasma polymerization in a glow discharge, and its application were described. The recently developed plasma polymerization replica technique was used to prepare ultrathin films from naphthalene monomer gas on the surface of a newly cleaved sodium chloride crystal or on cover glass. The film was floated off on water or hydrofluoric acid solution to free it from the base. The plasma-polymerized naphthalene support film (PNS) prepared in this way was shown to have excellent properties by its application to negative staining of virus antigen particles and by the observation of whole ultrathin sections of animal tissue mounted on a 2 x 1 mm single slot grid. Features of the new support film are (1) its ease of preparation as a clean, very thin film of less than 10 nm, (2) its amorphous texture and high transparency to electrons, (3) its mechanical strength, resistance to heat and chemicals, and electron bombardment, and (4) its smooth and slightly hydrophilic surface. The PNS would be useful for both routine and high-resolution electron microscopy.