2, University of Illinois at Chicago, Chicago, Illinois, United States
Nanomachines are devices fabricated in nanoscale which can be applied in making nanorobots, nanomotors, etc. The combination of various nanomaterials with controlled distributions can contribute to building nanomachines containing multiple functionalities (such as optical, electromagnetic, acoustic, or chemical energy functions).1, 2 However, to date, due to the limited resolution and precision caused by multiple operations, most of the reported nanomachines do not exhibit a strict size of “nano” but actually “microsize”. Besides, the most widely used methods (top-down lithography and bottom-up assembly of nanoscale building blocks) usually suffer from complex steps, small-scale production, and large time consumption. Thus, the capability of producing nanomachines with complicated structures and sophisticated functionalities are also limited.
In order to solve the problems mentioned above, in here, we propose a new nanomanufacturing strategy named acoustic field-assisted stereolithography (AFS). Briefly, a 3D part is first sliced into a set of horizontal planes via computer model and each slice is converted into a 2D image for projecting onto the photocurable liquid resin to cure that layer. With the help of piezoelectric actuator generating acoustic waves, the particles in the liquid resin are patterned and self-assembled along the standing acoustic waves (SAW). The projected 2D image then solidifies the patterned particles in liquid resin with desired geometries. As a result, a 3D part is fabricated by stacking up these 2D layers.
The preliminary simulation results obtained by COMSOL Multiphysics showed that a 1D surface SAW pattern can be obtained when a pair of SAW sources are placed in parallel and the corresponding particle trajectory results also give the pattern with parallel particle lines. Moreover, when two pairs of SAW sources placed orthogonal to each other are applied, 2D surface SAW pattern and 2D net particle pattern are achieved, suggesting the pattern of particles can be easily tuned by adjusting the SAW sources. We believe this strategy could provide a better guideline for the future nanomachines fabrication with high design flexibility and fast production speed that the traditional nanomanufacturing cannot provide.
(1) Xia, B. H.; Wang, J.; Tian, Y.; Chen, Q.; Du, X.; Zhang, Y. Ferrofluids for Fabrication of Remotely Controllable Micro-Nanomachines by Two-Photon Polymerization. Adv. Mater. 2010, 3204–3207.
(2) Kim, K.; Guo, J.; Xu, X.; Fan, D. L. Recent Progress on Man-Made Inorganic Nanomachines. Small 2015, 4037–4057.