Inducing surface hydrophobization on cornstarch film by SF6 and HMDSO plasma treatment.

The development of thermoplastic materials based on starch has become a promising alternative for reducing plastic waste. To this end, plasma treatments were used to enhance the hydrophobicity of cornstarch films. Cornstarch films plasticized using glycerol and distilled water were prepared by casting. A surface modification method was employed using different precursor gases, HMDSO and SF(6), and a combined treatment using HMDSO followed by SF(6) (HMDSO/SF(6)) and then the reverse, using SF(6) first followed by HMDSO (SF(6)/HMDSO). The results indicated that the induced surface morphology determines the contact angle. It was observed that all films became hydrophobic, and films that were initially treated with SF(6) showed the greatest hydrophobicity if no further coating was applied, or if the treated surface was further coated using HMDSO. Under both of these treatment conditions the contact angle was greater than 110°.