Design of microfluidic radionuclide sensors: Combining microscale 3D printing based on 2-photon polymerization with nanoscale polymer brush scintillators

Abstract

Development of miniature sensors for radionuclides is a challenging goal. In this paper we have applied specially developed vinyl-functionalized organic fluorophores for fabrication of nanoscale polymer brush scintillator coatings on artificially created 3D mesoporous structures. The applied 3D printing based on 2-photon polymerization is a modern approach, which extends the concept of additive manufacturing to the micro/nano-scale. One of the fundamental limitations of the 3D printing based on 2-photon polymerization (2PP) is a limited range of suitable photo-resins and, thus, limited functionalities of the resulting structures. To address this challenge, various post-processing technological steps, such as overcoating with conformal oxide layers and/or pyrolysis have been suggested. In this study, we demonstrate how chemical modification of 3D printed polymer structures with nanoscale polymer brush scintillators can be applied as a viable technological strategy for microfluidic radionuclide sensors. Application of new polymerizable organic fluorophores allowed “grafting to” or “grafting from” modifications of the photoresist surface with high concentration and precisely controlled location of the active scintillating units within the coating.