3-dimensional (3D) porous graphene is a promising platform for applications such as catalysis, sensors, and energy storage. In this thesis, bicontinuous interfacially jammed emulsion gel (bijel) templates are formed and chemically and thermally processed into sacrificial porous Cu-Ni alloy scaffolds which in turn are used for chemical vapor deposition (CVD) of graphene. Metal scaffolds formed from the bijel structure have large specific surface area and inherit the co-continuous property from their parent bijel. However, graphene grown via CVD on bicontinuous nickel scaffolds (biNi) will typically produce thick graphene layers due to the high carbon solubility in Ni unless the CVD growth is limited to short growth times of a few seconds. In the latter case, number of layers may be variable across the sample due to difficulties in controlling deposition kinetics in short growth times. In addition, thick graphite layers may form in the Ni grain boundaries leading to highly non uniform number of layers in 3D samples. Previous reports have shown that the number of layers and uniformity of CVD graphene can be controlled when using the Cu-Ni alloys as scaffolds. In this case, research has been limited to CVD growth on 2-dimensional Cu-Ni alloy surfaces. Here, in this thesis, the fabrication of 3D bicontinuous Cu-Ni alloy metal scaffolds(bi-CuNi) are successfully achieved. By varying electrochemical processing parameters, bi-CuNi with porous morphology containing 46.8% and 35.8% Cu in weight percentage are produced. When comparing the morphology and number of layers of resultant CVD graphene growth on the alloy scaffolds using the same CVD growth parameters on both samples, Raman spectroscopy measurements show many regions with a high 2D mode intensity with the higher Cu alloy concentration in the scaffold. Raman analysis showing that 3D graphene from bi-CuNi via CVD (bi-CuNi-3DG) exhibits turbostratic stacking in many regions of the sample. Turbostratic graphene can exhibit similar properties as single-layer graphene (SLG), indicating that emphasis on tuning physical properties of scaffold alloys has promise to yield 3D graphene structures with excellent electronic properties. In future work, precise control of Cu concentration in bi-CuNi is expected to control both graphene layer number and stacking, and thereby the electronic properties of the resultant 3D graphene architectures for numerous applications.

During recent decades gold nanorod has been found very interesting due to their optical and thermal characteristics which make them suitable for different applications. Many interesting applications are optical application because of rod’s strong, special range of plasmon resonances, such as biotechnological imaging and sensing, surface-enhanced raman scattering and metamaterials, and these applications’ performances can be impaired by polydispersity and low yield of gold nanorod when using seed-mediated method. Since seed-mediate approach is the most convenient and cheap method making gold nanorod, so it is necessary to find ways to optimize this method. In this research, first, we focus on relationship between shapes of gold nanorods and several factors exist in forming process due to its unique surface plasmon resonance and try to find an effect way to optimize this formation. Second, we put an effort to explain the mechanism of whole formation of rods by designing experiments testing rods’ properties and directly observing rods through SEM. Experimental results are shown as we predicted, strong acid environment with slowly stirring during rods forming process can optimize seed-mediate approach and mechanism of it is: growth isotropically at first, when seeds’ size are up to 6nm, they change to growth anisotropically due to CTA−Br−Ag+ capping agents forcing rods growth in specific direction.

Carbon is both abundant and functionally versatile due to the variability of orbital hybridization of carbon atoms forming linear, planar, and tetrahedral bonds leading to many allotropes. Different allotropes exhibit different physical properties such as electrical conductivity, surface area, and surface chemistry. The work presented here focuses on aromatic carbon materials and examines the tunability of physical properties, molecular to macroscopic structural formation, and importance in environmental applications, specifically soot pollution mitigation and next-generation single atom catalysis.

First, scanning tunneling microscopy (STM) experiments explore the intermolecular interactions of coronene (C12H24), a polycyclic aromatic hydrocarbon hypothesized to play a key role in incipient soot formation. The hazardous impacts of incipient soot – including lengthy suspension in the earth’s atmosphere and deep penetration into human respiratory systems – may be circumvented through an improved understanding of soot formation. Observations of coronene clusters reveal structures strikingly similar to recent models of clusters hypothesized to initiate soot formation. In contrast to mature soot, cluster surfaces are composed primarily of molecular edges. These findings have important implications for how additional molecules attach and become incorporated into growing soot particles.

Second, a first principles approach is used to identify how the local molecular environment on a graphene support can be used to stabilize a single platinum atom catalyst. Inspired by visions of achieving ultimate cost-effectiveness and performance, a single atom catalyst represents the most efficient use of precious metals while concurrently offering the potential for high chemical activity. Density functional theory results indicate that pyridinic nitrogen-doped graphene is a promising candidate to support a single Pt atom acting as a catalyst that is resistant to poisoning and enhances carbon monoxide oxidation efficiency. Experimental efforts demonstrate a pathway towards developing these supports, using bicontinuous interfacially jammed emulsion gels as templates for the growth of three-dimensional, porous graphene. STM, X-ray photoelectron spectroscopy, and Raman spectroscopy characterize the resultant architectures, relating nanoscale observations to macroscale properties such as specific surface area and mechanical strength.

This work – examining aromatic carbon materials – demonstrates how surface science techniques can unravel self-assembly and the physics that shape our macroscale environment.

Two-dimensional (2D) materials such as graphene have been a topic of intense study as these atomically thin materials have shown enhanced characteristics ideal for applications such as renewable energy storage and electrochemical sensing, which has led researchers into a frenzy akin to that of prospectors during the gold rush. While there still is gold to be found, there is also fool’s gold when systematic studies are not performed. In order to develop new processes for fabricating 3D high surface area architectures, we investigated mechanisms at a fundamental level throughout this work. It is known that the surfaces of freestanding 2D graphene sheets exhibits record-breaking electrical and thermal conductivity, remarkable chemical stability, mechanical strength, and naturally high specific surface area, however, current 2D techniques lay the graphene sheets onto substrates, typically decreasing electron transport and always reducing accessible surface area. In order to use sides of a graphene sheet for applications that require high surface area, we took inspiration from origami. A single paper cannot support itself, but when it becomes part of a 3-dimensional (3D) structure, support becomes natural. The first phase of my work involved the use of minimal surface inspired 3D nickel templates to create free-standing graphene structures with inherited morphology, resulting in porous well-defined sponge-like structures of free-standing graphene. The concept of graphene shaped into minimal surfaces architectures is of great interest; theories predict unique mechanical properties, such as a young’s modulus of 1 TPa for single crystal graphene and an exceptionally high stiffness for minimal surface architectures. Few studies have been performed of fabricating graphene architectures with well defined pore sizes, co-continuous pores, and controlled layer thickness needed for enhancing mass transport and electronic conductivity. Studies were also performed involving atomistic control of impurities of these 3D graphene-based structures to effect electronic structure and chemical properties of graphene, creating a tunable range of characteristics for this multifunctional material. 3D graphene in minimal surface architectures shows potential for enhancing the capabilities of standard carbon-based applications and creating niche applications, but only when key challenges of controlling architecture and graphene quality are addressed.

Investigating the mechanical behavior of lipid bilayer membranes is essential to understanding important cellular processes, such as morphogenesis, motility, drug delivery, mechanotransduction, metastasis, and focal adhesion. The mechanical properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles grafted with different 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-2000-N-[3-(2-pyridyldithio) propionate] (DSPE-PEG-PDP) concentrations were studied using Atomic Force Microscopy-Force Spectroscopy (AFM-FS) under buffer environment. The concentration of DSPE-PEG-PDP incorporated into POPC vesicles was systematically varied from 0 mol% to 10 mol%. By increasing DSPE-PEG-PDP concentration from 0 ‒ 10 mol%, vesicle size decreases, breakthrough distance increases, breakthrough force decreases, and the Young’s modulus decreases slightly. We also observe two E values exist at 5%, suggesting the existence of two conformations. PEG-grafted vesicles are sterically stabilized due to the presence of dangling PEG chains outside the vesicle membrane. The aim of this study is to examine the relationship between vesicle rigidity and vesicle stability.

Periodic metal nanoparticle arrays possess electromagnetic properties useful for metamaterials, light trapping, and molecular sensing, such as surface enhanced Raman spectroscopy (SERS). The localized surface plasmon resonance (LSPR) of these arrays depends on the material, periodicity, size, and spacing of nanoparticles, all features typically best controlled by traditional top down nanofabrication techniques, such as electron beam lithography. However, such fabrication methods are not realizable commercially. Bottom-up methods are increasingly being explored for alternative nanofabrication techniques in order to achieve high throughput and inexpensive fabrication. I present here multiple unique techniques for facile, inexpensive fabrication of nanostructures for biosensing. In the first technique, I fabricate 20 nm Au nanoparticle nanocluster assemblies onto a chemically functionalized diblock copolymer film, through electrophoresis and convective assembly, attaining interparticle spacings of < 1 nm. Norepinephrine is detected at 200 parts per billion using SERS, due to the high enhancement fields of the cluster. This is a cheap, high through put, and commercially accessible process. The second technique uses thermally responsive, pre stressed polyolefin (PO) film to reduce bow tie arrays by 50% in triangle area and up to 77% in tip to tip spacing, by heating in a convection oven. Reduction of the arrays shows tunability (100 nm blue shift) of the plasmon resonance, as well as potential for facile generation of hot spots for SERS. I also present work on tunable nanopillars using the polyolefin film, and on SiC nanopillar arrays, for the excitation of localized surface phonon polariton modes (SPhP), as potential low loss alternatives to plasmonics. FTIR reflectance spectroscopy measurements show the nanopillar arrays to confine infrared light with the emergence of localized SPhP modes, which exhibit dependence on pillar diameter and inter pillar spacing. Extreme light confinements and low losses are attained, with Q factors higher than the best plasmonic systems. Finally, I present work using electron beam lithography in tandem with the poyolefin film to achieve advanced plasmonic structures.

Periodic metal nanostructure arrays possess electromagnetic properties useful for metamaterials, light trapping, and molecular sensing, such as surface enhanced Raman spectroscopy (SERS). The localized plasmon resonance frequency of these arrays depends on the material, periodicity, size, and spacing of nanoparticles. While bottom down fabrication techniques are often inexpensive and more realistic on a manufacturing scale than top down fabrication alternatives, tuning nanostructure parameters to modify optical properties is currently limited. In my work, I have demonstrated the potential for scaling down and tuning nanostructures fabricated by bottom up techniques, by using a thermally responsive polyolefin (PO) film in conjunction with nanosphere lithography (NSL). By heating the patterned substrate in a convection oven, I have successfully fabricated both nanopillar arrays with tunable dimensions, which can be used in antireflective applications, and tunable gold nanotriangle arrays, which have previously been shown to generate SERS enhancements due to the hot spots between two tips. Reductions in area as great as 95% have been achieved. Reflectance spectroscopy shows the tunabilty of the triangle array to tune the plasmon resonance. These findings are confirmed by subsequent SERS experiments. I also present here work on localized surface phonon polariton modes (SPhP), which are potential low loss alternative to plasmonics. 6H-silicon carbide nanopillar arrays are fabricated to generate localized SPhP modes, which are measured using FTIR reflectance spectroscopy and Raman spectroscopy. The measured SPhP modes are found to have exceptionally narrow line widths, giving high Q factors and low losses, and in many cases are Raman active.

Self-assembly typically utilizes thermodynamic driving forces to organize building blocks ranging from atoms to nanoparticles into static assemblies. Self-assembled structures often exhibit unique properties such as lowering catalytic energy barriers or tuning light-matter interactions. This requires understanding how to design and fabricate surfaces at atomic and molecular length scales where localized forces such as magnetic or electric fields drive complex chemical behavior. The characterization of nanoscale chemical behavior necessary for complete understanding of these processes is a significant challenge. In terms of catalysis, high throughput density functional theory modeling of a range of earth abundant transition metal atoms (V, Fe, Mo, Ta) supported on two types of graphene surface defects (bare, N-doped) demonstrate relatively lower activation energy barriers for systems with higher spin states at frontier orbitals near the Fermi energy; CO oxidation on Ta and V SAC have decreases in activation barrier energies of 27% and 44%, respectively. Effective Raman and infrared (IR) modeling approaches have been developed to interpret the effects of charge transfer and electric fields on chemical bonding and molecular orientation in plasmonic nanogaps. Even non-plasmonic enhancement of electric fields on gold surfaces is shown to alter molecular orientation and selectively enhance resonance modes in vibrational force spectra, which correlates to IR spectroscopy. The insights provided by this work further elucidates nanoscale chemical reactions crucial for next generation catalytic design as well as fundamental understanding of dynamic chemical behavior during self-assembly processes.