Plasma Chemistry and Plasma Processing ( IF 2.178 ) Pub Date : 2019-12-04 , DOI: 10.1007/s11090-019-10049-y Shaham Shafaei; Lanti Yang; Marcel Rudolph; Peter Awakowicz
For many applications of polycarbonate (PC) from packaging to micro-electronics improved barrier properties are necessary. In this contribution, silica thin films were deposited from hexamethyldisiloxane/oxygen (HMDSO/O2) on polycarbonate substrate in three step plasma processes by combining a microwave (MW) surface wave discharge of 2.45 GHz with an optional radio-frequency (RF) bias of 13.56 MHz. The influence of interlayer thickness, HMDSO flow and oxygen to HMDSO ratio on barrier performance for three step-coating processes was investigated. The morphology and surface properties of the coated surface of PC were studied by atomic force microscopy (AFM). The surface topography showed a silica particles distribution on the PC substrate with relatively smooth surface roughness. AFM-QNM provides more insight into the surface morphology and stiffness. The results identify the coating structure for PC film coated with and without bias. High barrier improvement of the deposited films on PC substrates was obtained after plasma silicon coating process with a barrier improvement factor up to 337. It was found that the deposition process is optimal for food packaging applications by using combined MW-RF PECVD technology.