Hydrogen (H 2 ) sensors that can be produced en masse with cost-effective manufacturing tools are critical for enabling safety in the emerging hydrogen economy. The use of melt-processed nanocomposites in this context would allow the combination of the advantages of plasmonic hydrogen detection with polymer technology; an approach which is held back by the slow diffusion of H 2 through the polymer matrix. Here, we show that the use of an amorphous fluorinated polymer, compounded with colloidal Pd nanoparticles prepared by highly scalable continuous flow synthesis, results in nanocomposites that display a high H 2 diffusion coefficient in the order of 10 –5 cm 2 s –1 . As a result, plasmonic optical hydrogen detection with melt-pressed fluorinated polymer nanocomposites is no longer limited by the diffusion of the H 2 analyte to the Pd nanoparticle transducer elements, despite a thickness of up to 100 μm, thereby enabling response times as short as 2.5 s at 100 mbar (≡10 vol. %) H 2 . Evidently, plasmonic sensors with a fast response time can be fabricated with thick, melt-processed nanocomposites, which paves the way for a new generation of robust H 2 sensors.

A bio‐based polymeric ink for stereolithography developed through a two‐step solvent‐free process is herein proposed. Specifically, low‐molecular‐weight poly(hydroxybutyrate) (PHB)‐diol oligomers are prepared via molten transesterification of bacterial PHB with 1,4‐butanediol. Transesterification conditions such as diol concentration, catalyst amount, and reaction time are studied for optimizing the final oligomers’ molecular weight and structural features. In the second step, the oligomeric hydroxyl terminals are converted into methacrylate moieties through a solvent‐free end‐capping reaction and diluted in propylene carbonate in order to obtain a photo‐polymerizable ink with suitable viscosity. The ink is UV‐cured, and the obtained material properties are investigated by FT‐IR and differential scanning calorimetry measurements. The proposed method provides a valuable and environmentally friendly alternative to currently available synthetic routes, overcoming their typical disadvantages related to the used solvents and harsh conditions. Moreover, it opens up a sustainable route for converting polyesters into functionalized oligomeric derivatives, which can potentially find application in 3D printing of customized biomedical devices.

Two-steps method to determine hydroxyl value and molecular weight of hydroxyl terminated polymers by 19F-NMR measurements.