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

• Published in: Carbohydrate polymers 2013-01, Vol.91 (2), p.675-681
• Main Authors: Bastos, Daniele C., Santos, Anastácia E.F., da Fonseca, Marta D., Simão, Renata A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Coated Materials, Biocompatible - chemistry; coatings; contact angle; corn starch; Exact sciences and technology; Food industries; Fundamental and applied biological sciences. Psychology; gases; glycerol; HMDSO; Hydrophobic and Hydrophilic Interactions; hydrophobicity; Membranes, Artificial; Microscopy, Atomic Force; Microscopy, Confocal; Natural polymers; Physicochemistry of polymers; Plasma; SF6; Siloxanes - chemistry; Starch; Starch - chemistry; Starch and polysaccharides; Starch and starchy product industries; sulfur hexafluoride; Sulfur Hexafluoride - chemistry; Surface Properties; thermoplastics; wastes
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2012.08.031

► Plasma deposited films form a hydrophobic and soft coating. ► SF6 treatment induces an increase in roughness in both starch and HMDSO films. ► SF6 reticulation on starch was proved by elastic modulus increase. ► Plasma treatment can induce starch hydrophobization. ► The most hydrophobic film (SF6/HMDSO) showed an increase of the O/C and O/Si ratios. 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 SF6, and a combined treatment using HMDSO followed by SF6 (HMDSO/SF6) and then the reverse, using SF6 first followed by HMDSO (SF6/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 SF6 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°.