Direct Synthesis of Gold Nanoparticles in Polymer Matrix

Abstract

We report an original method for directly fabricating gold nanoparticles (Au NPs) in a polymer matrix using a thermal treatment technique and theoretically and experimentally investigate their plasmonic properties. The polymeric-metallic nanocomposite samples were first prepared by simply mixing SU-8 resist and Au salt with different concentrations. The Au NPs growth was triggered inside the polymer through a thermal process on a hot plate and in air environment. The Au NPs creation was confirmed by the color of the nanocomposite thin films and by absorption spectra measurements. The Au NPs sizes and distributions were confirmed by transmission electron microscope measurements. It was found that the concentrations of Au salt and the annealing temperatures and durations are all crucial for tuning the Au NPs sizes and distributions, and, thus, their optical properties. We also propose a simulation model for calculations of Au NPs plasmonic properties inside a polymer medium. We realized that Au NPs having large sizes (50 to 100 nm) play an important role in absorption spectra measurements, as compared to the contribution of small NPs (<20 nm), even if the relative amount of big Au NPs is small. This simple, low-cost, and highly reproducible technique allows us to obtain plasmonic NPs within polymer thin films on a large scale, which can be potentially applied to many fields.

Silver Nanoparticles’ Localized Surface Plasmon Resonances Emerged in Polymeric Environments: Theory and Experiment

“…Functional polymer composites with embedded metal nanoparticles have been fabricated using numerous methods, including reduction of metal salts, plasma polymerization combined with metal deposition, co-evaporation of metals and organic components, and co-sputtering. Further details on the synthesis methods of such composites can be found in references [17,18,29].…”

Flexible Soft-Printed Polymer Films with Tunable Plasmonic Properties

“…1,3,28 Evaporation of thin Au films, followed by high-temperature annealing, is a convenient approach to obtain uniform coverage of substrate surfaces by structures such as nanoparticles (AuNPs) or nanoislands (AuNIs) on solid substrates with well-defined optical and morphological properties that uniformly fill desired surfaces. 29,30 Various applications require the incorporation of plasmonic NPs not just onto/into solid inorganic materials but organic polymers (e.g., PMMA), biopolymers (proteins), 31−33 and polysaccharides to form the so-called plasmonic nanocomposites, 34 that provide additional functionality such as substrate flexibility. 35,36 Fabrication of metal NPs in a polymer matrix is challenging since NPs usually aggregate alternating their SPR characteristics.…”

“…Various applications require the incorporation of plasmonic NPs not just onto/into solid inorganic materials but organic polymers (e.g., PMMA), biopolymers (proteins), − and polysaccharides to form the so-called plasmonic nanocomposites, that provide additional functionality such as substrate flexibility. , Fabrication of metal NPs in a polymer matrix is challenging since NPs usually aggregate alternating their SPR characteristics. In recent years, controlled assembly of NPs directly on/in polymeric substrates has been proposed based on the self-assembly of NPs from solution. ,, Growing Au NPs on a flexible substrate enables simple mechanical control of the plasmonic coupling via its stretching/shrinkage . Plasmon-coupled AuNPs incorporated in flexible stretched shape-memory polymers were demonstrated for mechanical and thermal sensing, and opto-mechanic devices. , …”

“…Various applications require the incorporation of plasmonic NPs not just onto/into solid inorganic materials but organic polymers (e.g., PMMA), biopolymers (proteins), 31 − 33 and polysaccharides to form the so-called plasmonic nanocomposites, 34 that provide additional functionality such as substrate flexibility. 35 , 36 Fabrication of metal NPs in a polymer matrix is challenging since NPs usually aggregate alternating their SPR characteristics.…”

“…In recent years, controlled assembly of NPs directly on/in polymeric substrates has been proposed based on the self-assembly of NPs from solution. 34 , 37 , 38 Growing Au NPs on a flexible substrate enables simple mechanical control of the plasmonic coupling via its stretching/shrinkage. 39 Plasmon-coupled AuNPs incorporated in flexible stretched shape-memory polymers were demonstrated for mechanical and thermal sensing, 40 and opto-mechanic devices.…”