Surface modification of maize starch films by low-pressure glow 1-butene plasma

Plasma polymerisation was used to modify the surface of maize starch films in order to reduce their water affinity. Films were prepared by casting starch suspensions heated for different periods of time. Glycerol was added as a plasticiser. To produce a hydrogenated-carbon coating, films were exposed to low-pressure glow plasma generated in 1-butene gas from a radio frequency diode sputtering system. Atomic force microscopy (AFM) was used to investigate possible changes in surface morphology and roughness of plasma-coated films in relation to the corresponding substrates. AFM phase contrast images at high magnification revealed characteristic features at the surfaces of plasma-coated starch films. Water absorption experiments and contact angle measurements were carried out to verify the effect of deposited layers on the water sensitivity of those surface-modified films. The results indicated that the coating process reduced significantly the hydrophilic character of starch films.