Mechanical nanolattices printed using nanocluster-based photoresists

• Published in: Science (American Association for the Advancement of Science) Vol. 378; no. 6621; pp. 768 - 773
• Main Authors: Li, Qi, Kulikowski, John, Doan, David, Tertuliano, Ottman A., Zeman, Charles J., Wang, Melody M., Schatz, George C., Gu, X. Wendy
• Format: Journal Article
• Language: English
• Published: Washington The American Association for the Advancement of Science 18.11.2022
• Subjects: Mechanical properties; Metal clusters; Nanoclusters; Organic chemistry; Photoinitiators; Photons; Photoresists; Polymers; Porosity; Three dimensional printing
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abo6997

Natural materials exhibit emergent mechanical properties as a result of their nanoarchitected, nanocomposite structures with optimized hierarchy, anisotropy, and nanoporosity. Fabrication of such complex systems is currently challenging because high-quality three-dimensional (3D) nanoprinting is mostly limited to simple, homogeneous materials. We report a strategy for the rapid nanoprinting of complex structural nanocomposites using metal nanoclusters. These ultrasmall, quantum-confined nanoclusters function as highly sensitive two-photon activators and simultaneously serve as precursors for mechanical reinforcements and nanoscale porogens. Nanocomposites with complex 3D architectures are printed, as well as structures with tunable, hierarchical, and anisotropic nanoporosity. Nanocluster-polymer nanolattices exhibit high specific strength, energy absorption, deformability, and recoverability. This framework provides a generalizable, versatile approach for the use of photoactive nanomaterials in additive manufacturing of complex systems with emergent mechanical properties. Metal nanoclusters improve printing To enhance the properties of two-photon three-dimensional (3D)–printed polymeric structures, photoinitiators are added to increase the formation of radicals and to improve the polymerization process. However, each polymer may require a specific initiator, and the organic molecules typically used do not enhance the properties of the finished product. Li et al . report an improvement in two-photon 3D printing in which atomic metal clusters are used as two-photon absorbers to enhance the mechanical properties of the printed structures. The authors reveal the formation of a complex architecture with tunable and hierarchical porosity showing high mechanical strength and stability. —MSL Nanocluster-based photoresists enable 3D printing of polymer nanocomposites with enhanced mechanical strength and stability.