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

Abstract

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°.

Acetylene coating on cornstarch plastics produced by cold plasma technology

“…SF 6 plasma treatment substantially increased the surface roughness, as described elsewhere . The RMS roughness increased from 25 nm, for untreated films, to 50 nm after treatment.…”

“…After SF 6 plasma treatment, the contact angle improved; an initial angle of 120° was observed. Upon SF 6 plasma treatment, the film surface became reticulated and thus stably hydrophobic as previously reported . However, when this film was further coated with C 2 H 2 (SF 6 /C 2 H 2 ), the initial contact angle decreased to 90° and the surface wettability became unstable, with the contact angle decreasing to 60° after 450 s of contact.…”

“…It is mostly water soluble, difficult to process, and brittle. Starch is not a true thermoplastic, but when submitted to a thermo‐mechanical process in the presence of a plasticizer, such as water, glycerol or sorbitol, it loses its granular structure and becomes semicrystalline, similar to the behavior of a molten thermoplastic named thermoplastic starch or TPS .…”

“…Cold plasma technology has emerged as a promising tool to overcome the high hydrophilicity of starch film surfaces . Gas‐discharge plasma can be characterized as a partially ionized gas containing neutral particles as well as equal numbers of negative electrons and positive ions.…”

Effect of H2S Plasma Treatment on the Surface Modification of a Polyethylene Terephthalate Surface

“…Oxygen and nitrogen-containing plasmas (O 2 , CO 2 , N 2 , NH 3 ) or their mixtures with noble gases, such as He and Ar, are commonly used for surface hydrophilization [1,2,3,4,5]. In contrast, fluorine-containing plasmas (CF 4 , SF 6 ) are used for surface hydrophobization [6,7]. Recently, a few papers have reported on tailoring the surface properties by SO 2 plasma [8,9,10].…”