3D Printing of Cantilever-Type Microstructures by Stereolithography of Ferromagnetic Photopolymers

Abstract

In the present work, prototypes of polymeric cantilever-based magnetic microstructures were fabricated by means of stereolithography (SL). To this end, a UV-curable system suitable for high-resolution SL-processing was formulated by blending a bifunctional acrylic monomer with photoinitiator and visible dye whose content was tuned to tailor resin SL sensitivity. Subsequently, to confer ferromagnetic properties to the photopolymer, two different strategies were implemented. A two-step approach involved selective deposition of a metal layer on photopolymer SL-cured surfaces through an electroless plating process. On the other hand, SL-processable ferromagnetically responsive nanocomposites (FRCs) were obtained by directly loading magnetite nanoparticles within the photopolymer matrix. In order to achieve high-printing resolution, resin SL sensitivities were studied as a function of the various additives contents. Photocalorimetric analyses were also performed to investigate the photopolymer conversion efficiency upon light exposure. High-performing formulations were characterized by reduced penetration depth (<50 μm) and small critical energies thus enabling for fast printing of micrometric structures. Finally, the self-standing characteristics of the resin combined with the layered-fashion deposition typical of the 3D printing technologies were exploited for the fabrication of cantilever (CL)-based beams presented as possible magnetic sensors. As a demonstration of the feasibility of the two approaches, the magnetic beams were successfully actuated and their sensing performances in terms of static deflection vs applied magnetic field applied were qualitatively studied. Being not restricted to CL-based geometries, the combination of SL-printing with the formulation of novel smart photopolymers open the way toward the fabrication of high-customized complex 3D models integrating functional microstructures.

Electroless Metallization of Stereolithographic Photocurable Resins for 3D Printing of Functional Microdevices

“…23 The axis of the magnet was placed in correspondence of the part of the cantilever covered by the magnetic material. It was therefore collocated at half the length of the metallized part (3 mm/2 = 1.5 mm from the tip).…”

The Boom in 3D-Printed Sensor Technology

“…Caterina Credi and colleagues [38] provide a method to fabricate cantilever-type microstructures by stereolithography of ferromagnetic photopolymers used as possible magnetic field sensors (Figure 11E). The sensing performance in terms of static deflection vs applied magnetic field is the sensing mechanism, and was qualitatively studied in theirs research.…”

“…Reproduced from [36], with permission from IEEE © 2015; ( E ) Array of cantilevers ( b ); The high precision at the interface of the two resins ( c ); Example of superimposition of optical images acquired for the sample in its initial position (0) and when the magnet approached ( d ). Reproduced from [38], with permission from the American Chemical Society © 2016.…”

Advances and Future Perspectives in 4D Bioprinting

“…For example, Gomez et al used a two‐photon stereolithography approach to fabricate microcantilever‐based biosensors using molecularly imprinted polymers. Similarly, Credi et al used stereolithography technique to make cantilevers containing magnetic nanocomposites. These cantilevers can be used to study cell behavior and function.…”