Demonstration of Copper:pLA-like nanocomposite-based distributed Bragg reflector gas sensor

Plasma polymerization, commonly considered a type of plasma-enhanced chemical vapour deposition (PECVD), is a popular method for depositing organic thin films.However, it often produces films with limited molecular complexity due to the necessity to use relatively low molar mass precursors that can be vaporized.To address these limitations, plasma-assisted vapour thermal deposition (PAVTD) was developed.In PAVTD, a solid polymer undergoes thermal degradation (evaporation) in a crucible, producing oligomers with higher molar masses (10 2 -10 3 g.mol - ) than typical PECVD precursors.These oligomers are then re-polymerized in RF plasma, allowing PAVTD films to exhibit properties characteristic of classical polymer physics and chemistry, a rarity for plasma polymers.This process enables the precise control of properties such as biodegradability and hydrolyzability, as demonstrated in polylactic acid (PLA)-based films.PAVTD effectively bridges the gap between classical and plasma polymers.To enhance stability and deposition rates, continuous-PAVTD has been developed using standard FDM 3D printing filaments, achieving deposition rates up to several nanometers per second.This advancement addresses deposition duration and stability issues, making PAVTD a practical tool for studying plasma polymerization.Furthermore, PAVTD can be combined with other vacuum-based thin film deposition techniques like gas aggregation source of nanoparticles (GAS).This capability was demonstrated by fabricating Cu:PLA-like nanocomposite-based distributed Bragg reflector (DBR), where the reproducibility of the deposition rate matters significantly.This reflector was tested as a gas sensor for ethanol vapours, exhibiting strong reflectance peak shifts.