Research On Gold Foam Composite Materials And Their Optical Properties

As a type of structural material,gold foam composite materials possess adjustable porosity,density,and a large specific surface area,making them a frontier in material physics research.Serving as functional materials,gold foam composites have been extensively applied in fields such as aerospace,construction engineering,and environmental protection engineering for damping,sound absorption and insulation,thermal resistance and flame retardancy,and electromagnetic shielding.In particular,the application of gold foam composite materials in controlled nuclear fusion has attracted considerable attention.Noble metal core-shell artificial materials exhibit tunable localized surface plasmon resonance and localized surface-enhanced light absorption-energy conversion effects.High-purity,high atomic number Z metal foams,due to their localized surface plasmon resonance properties,serve as excellent energy conversion materials.Generally,gold foam can be used as cavity target material in high-energy-density physics to study the process of enhancing X-ray energy conversion efficiency,thereby effectively reducing laser-driven energy.In this study,micrometer-sized polystyrene(PS)microspheres were prepared using an improved soap-free emulsion polymerization method,and two metallic-insulator quasi-2D core-shell structures,PS@Au and PS@Au@AuNPs,were fabricated by employing an improved surface gold seed(Au)and monodisperse gold nanoparticle(AuNPs)surface selfassembly growth method.By controlling the micro-nano geometric structure parameters,monodisperse and controllable core-shell composite structure units were designed and synthesized.Various conventional characterization techniques were utilized to investigate the optical properties of liquid-phase,powder,and thin film PS@Au and PS@Au@AuNPs foam materials.An optimized chemical component removal and physical degradation purification technology was developed to remove the PS template and its impurities,successfully preparing two types of hollow gold sphere-shell materials supported by oxidized graphene(OG): OG@Au and OG@Au@AuNPs.At the same time,a micropressure molding method was developed,producing high-purity,low-density gold foam thin films for use in shock wave experiments in inertial confinement fusion(ICF).Employing extended scaling laws and random matrix theory,the optical properties of PS@Au,PS@Au@AuNPs,and hollow gold foam structure materials were studied.The main research content and innovative points of this paper are as follows:(1)A mechanism for the growth of a graphene interface on the surface of goldcatalyzed polystyrene was proposed,and a polystyrene microsphere-coated gold core-shell structure with a graphene interface was designed.A nucleation,interface,and surface seed growth PS@Au technology method was developed,successfully preparing OG supported gold sphere-shell foam target materials,with the direct detection of gold-catalyzed polycrystalline graphene existing in the interface layer.Firstly,monodisperse polystyrene microspheres with adjustable inner sizes of 3-10 μm and monodisperse gold nanoparticles with adjustable size ranges of 6-14 nm were quickly prepared using an improved soap-free emulsion polymerization and redox method,serving as precursor self-assembly unit structures.Secondly,liquid-phase and powder 5 μm PS@Au structure materials were prepared using an improved gold surface seed growth method.Thirdly,a hollow gold shell supported by oxidized graphene was obtained through a chemical component removal method.Finally,after degradation and purification,a highpurity(>97 wt%)and low-density(19 mg/cm3)OG@Au gold foam structure target material was obtained,with the gold foam density being approximately one percent of the bulk material.The new gold sphere-shell material can be used as carbon-based devices and highpurity,low-density broadband absorption materials.Based on the scaling method,a strong coupling plasmon was found in the near ultraviolet(UV)region.In the near-infrared range,the samples exhibited adjustable bending effects.(2)A gold cage-coated polystyrene microsphere metal-insulator core-shell structure was designed,and a multiple self-assembly particle growth method for PS@Au surface gold nanoparticles was proposed.A two-step purification technique combining chemical extraction and physical degradation through tetrahydrofuran immersion and hightemperature degradation was developed.Successful preparation of 5-10 micron high-purity,low-density,and high specific surface area gold cage shell foam materials with UV-Vis-NIR(ultraviolet-visible-near infrared)broadband absorption was achieved.It was found that gold cage-coated polystyrene core-shell materials exhibit characteristics such as transverse electromagnetic hybridization and dual plasmon resonance absorption.Based on the improved metal sphere shell light absorption theory simulation and UV-Vis-NIR detection,the research results show that with the variation of micro-nano structural parameters,the gold aerogel sphere shell foam materials exhibit localized surface-enhanced energy conversion and bandwidth-tunable plasmonic phase transition properties.(3)A micro-pressure reconstruction assembly technique was developed,successfully preparing high-purity gold shell foam thin films with a density of approximately 1.5 g/cm3 and a thickness of about 28 μm.High-purity gold shell foam thin films were used for shock wave experiments on China’s Shenguang III prototype facility.The results showed that the gold thin films exhibit localized surface-enhanced X-ray energy conversion efficiency,and their material state possesses strong coupling characteristics different from those of gold foams prepared with silicon-based templates.Under micro-pressure conditions,it was found that the gold foam surface exhibits a fractal-percolation structure,while the interior possesses a polycrystalline foam structure composed of OG@Au@AuNPs.Furthermore,by optimizing the temperature and pressure of the heat treatment process,the results showed that at a heat treatment temperature of300°C,the high-purity gold foam thin film exhibits a multilayer structure with unique narrowband reverse plasmon resonance properties.Lastly,a micro-pressure reconstruction technique was explored.By maintaining the surface roughness of the thin film unchanged,the internal voids and collapse of the thin film were reduced,thus providing a new technical approach for the preparation of gold aerogel thin films.