Comparison of the Coating Structure of Silicon‐Based PECVD Coatings With Varying Organic Content

ABSTRACT This study examines the structural transition between plasma‐polymerized silicon‐oxide (SiO x ) and silicon‐organic (SiOCH) coatings with varying organic content. Using comprehensive characterization techniques on 13 samples with systematically varied oxygen‐to‐hexamethyldisiloxane ratios and energy densities, we found that SiO x barrier coatings unexpectedly exhibited higher porosity than SiOCH coatings. This suggests chemical composition impacts barrier performance more than nanopore structure. The transition from SiOCH to SiO x involves molecular‐level structural reorganization, likely due to absent Si‐C bonds in SiO x coatings, creating a more rigid SiO₂‐like cage structure. These findings provide crucial insights into structure‐property relationships of silicon‐based plasma coatings, essential for optimizing gas barrier functionality in applications like food packaging.