3D-Printing of Fluorinated Polymer-based Materials for Plasmonic Sensing

Doctoral thesis, 2023

Hydrogen attracts growing interest as a versatile energy carrier, serving as a fuel for cars, a heat source, or a reagent for chemical synthesis. At the same time, the demand for accurate and selective hydrogen sensors is increasing because of both safety concerns and the need for process monitoring. This thesis discusses plasmonic sensors as a viable option for hydrogen sensing and in particular the transition from 2D thin films to bulk production of plasmonic plastic nanocomposites via melt processing and 3D-printing. This thesis explores a processing methodology that has the potential to produce a broad range of plasmonic plastic nanocomposites by allowing for variation in both the type of nanoparticles and the polymer matrix.

First, different Au nanoparticles were compounded together with poly(lactic acid) (PLA) and poly(methyl methacrylate) (PMMA) and 3D-printed to demonstrate the versatility and processability of  plasmonic plastic nanocomposites. Secondly, Pd- and PdAu based composites with PMMA and Teflon AF as the polymer matrix were produced to create 3D-printed plasmonic hydrogen sensors. Furthermore, the hydrogen sensing kinetics and protective properties of the polymer matrix surrounding the Pd nanoparticles were evaluated. The use of PMMA:Pd nanocomposites resulted in a robust sensor, that offers good protection against carbon monoxide poisoning. Instead, Teflon AF:Pd nanocomposites facilitate fast sensing due to a high hydrogen diffusivity. To combine the advantages of both matrix polymers, a core:shell approach with a Teflon AF:Pd nanocomposite as the bulk material and PMMA as a surface coating is explored. This approach yields a sensor with a promising degree of carbon monoxide protection without affecting the fast sensor response of the Teflon AF:Pd nanocomposite. Evidently, the use of polymer nanocomposites is a promising avenue for the realization of fast and selective hydrogen sensors.