Strategies for Integrating Metal Nanoparticles with Two‐Photon Polymerization Process: Toward High Resolution Functional Additive Manufacturing

Abstract

This study reports the successful fabrication of complex 3D metal nanoparticle-polymer nanocomposites using two-photon polymerization (2PP). Three complementary strategies are detailed: in situ formation of metal nanoparticles (MeNPs) through a single-step photoreduction process, integration of pre-formed MeNPs into 2PP resin, and site-selective MeNPs decoration of 3D 2PP structures. In the in situ formation strategy, a phasetransfer method is applied to transfer silver and copper ions from an aqueous phase into a toluene solvent to disperse them in photoreactive monomers. The addition of a photosensitive dye, coumarin 30, facilitated the reduction of silver ions and improved the distribution of silver nanoparticles (AgNPs). This strategy is successfully used to produce other MeNPs, such as Cu and Au. The integration of pre-formed MeNPs enabled highly controlled NP size distribution within the 2PP 3D structures with high-fidelity To enable selective decoration of 2PP 3D surfaces with MeNPs, a multimaterial strategy is developed, with one of the resins designed for thiol-ene reaction, which demonstrated selective binding to AuNPs. The successful development of complementary strategies for integration of MeNPs into 2PP resins offers exciting opportunities for fabrication of MeNP composites with sub-micron resolution for applications from photonics to metamaterials and drug delivery.

Straightforward Manufacturing of 3D-Printed Metallic Structures toward Customized Electrical Components

“…36 Recently, Turyanska et al utilized thiol-ene resins in two-photon polymerizations and achieved the integration of metal nanoparticles within 3D structures through strong binding between metals and thiols. 37 Tuck et al introduced a thiolfunctionalized layer on 3D-printed polymers and utilized them as a strong adhesion layer during ELP. 38 Considering the fact that metals including Cu and Au can easily bind sulfur compounds and generate strong metal−sulfur bonds in solution, 39−41 we hypothesize that the presence of thiol functionalities on 3D-printed polymers could enable ELP without involving the catalytic activation process.…”

“…For example, Roppolo et al were able to graft organic dyes onto thiol-functionalized 3D-printed polymers . Recently, Turyanska et al utilized thiol-ene resins in two-photon polymerizations and achieved the integration of metal nanoparticles within 3D structures through strong binding between metals and thiols . Tuck et al introduced a thiol-functionalized layer on 3D-printed polymers and utilized them as a strong adhesion layer during ELP .…”

Hybrid aerosol jet μ-stereolithography additive manufacturing for fabrication of multi-material polymer step-index optics

“…An alternative approach is the multi-material additive manufacturing. Just recently, the possibility of combining two-photon-polymerization and multi-material printing has been investigated 10 , 11 . However, this approach is investigated for fabrication of mechanical rather than optical components.…”

“…Just recently, the possibility of combining two-photon-polymerization and multi-material printing has been investigated. 10,11 However, this approach is investigated for fabrication of mechanical rather than optical components. In contrast, we have recently presented a purely aerosol-jet-based process for fabricating STIN lenses, 12 which features a discretized version of a GRIN lens.…”

3D printing of inorganic nanomaterials by photochemically bonding colloidal nanocrystals

“…However, the printing resolution is limited by the nozzle size, and the weak interparticle forces are insufficient to support complex 3D structures. Alternatively, the two-photon polymerization process (12) can print arbitrary 3D structures of inorganic NC-polymer hybrids, where the NCs (especially the metal oxides) are physically embedded in (13,14) or chemically bonded to (15)(16)(17) photocurable resins. The inorganic mass fraction of these hybrids is below 50%.…”