2026 OC Regional Science Olympiad: Materials Science

Metal nanomaterials

Composed of pure metals at nanoscale (ex: gold, silver, platinum nanoparticles)

Metal nanomaterial applications

Catalysis, medical imaging, electronics

Metal-oxide nanomaterials

Composed of metal oxides (ex: titanium dioxide, zinc oxide)

Metal-oxide nanomaterial applications

Sunscreens, photocatalysts, sensors

Ceramic nanomaterials

Inorganic, non-metallic solids (high hardness, heat/corrosion resistant)

Ceramic nanomaterial applications

Aerospace, cutting tools, biomedical implants

Semiconductor nanomaterials

Quantum confinement affects electronic/optical properties (ex: cadmium sulfide, zinc selenide, silicon nanowires)

Semiconductor nanomaterial applications

Solar cells, LEDs, transistors

Carbon-based nanomaterials

Composed of carbon atoms at nanoscale

Graphene

Single layer of carbon atoms

Fullerenes

Spherical carbon cages

Carbon nanotubes

Cylindrical tubes of carbon

Carbon-based nanomaterial applications

Composites, electronics, energy storage

Nanomaterial dimensionality for application: 0D (zero dimensional)

Drug delivery, quantum dots in displays

Nanomaterial dimensionality for applications 1D (one dimensional)

Nanowires in sensors, nanotubes in composites

Nanomaterial dimensionality for applications 2D (two dimensional)

Graphene-based membranes, coatings

Nanomaterial dimensionality for applications 3D (three dimensional)

Nanoporous catalysts

Nanofluids

Fluids containing suspended nanoparticles

Nanofluid applications

Cooling systems, medical therapies

Crystalline structure

Atoms arranged in repeating 3D patterns

Common lattices

FCC, BCC, HCP

Amorphous nanomaterials

Atoms randomly arranged (not uniform)

Types of interatomic bonding

Ionic, covalent, metallic

Ionic bond

Nonmetal + Metal (gives)

Covalent bond

Nonmetal + Nonmetal (shares)

Metallic bond

Metal +Metal

Van der Waals

Weak, short-range attractions between molecules caused by magnetic poles

Hydrogen bonding

Strong type of intermolecular dipole-dipole attraction. Occurs between hydrogen and F, O or N

Dipole-dipole interactions

Attractive forces between polar molecules

Grain boundaries

The boundaries between crystals (grains) in a polycrystalline material

Hall-Petch relationship

Strength increases as grain size decreases

Surface area to volume ratio

As an object gets smaller, the surface area drastically increases compared to its volume

Surface energy

Energy required to create a unit of surface

Surface tension

For force per unit length at surface

Wetting angle

Measures how a liquid spreads on a surface

Hydrophobic

Large contact end, repels water

Hydrophilic

Small contact end, attracts water

Surfactants

Molecules with hydrophilic head and hydrophobic tail

Top-Down Synthesis

Breaking down bulk materials into nanomaterials (big -> small)

Top-Down: Mechanical Milling (4 steps)

1.) Bulk material placed into a heavy-duty container (mill)

2.) Heavy metal balls added

3.) The container spins/moves quickly, smashing the bulk material repetitively

4.) Result: nanomaterial

Top-Down: Lithography (4 steps)

1.) Solid flat slab of material

2.) Stencil is made using light, electron beams, or ions

3.) Chemicals or plasma remove the unmarked parts

4.) Smaller structure is the result

Top-Down: Sputtering (4 steps)

1.) Solid slab of material (the target) and object to coat (substrate) -> vacuum-sealed chamber (heavy gas)

2.) High voltage applied to gas -> plasma (fast ions attracted to target)

3.) Individual atoms removed from the bulk

4.) Loose atoms fly and land on the substrate

Bottom-Up Synthesis

Building nanostructures by stacking atoms or molecules on top of one another

Bottom-Up: Sol-Gel Process (4 steps)

1.) Form a liquid from chemicals (sol)

2.) Chemicals link together -> wet solid web (gel)

3.) Remove surrounding liquid -> dry, stiff sponge left

4.) Heat in an oven -> hard glass/ceramic

Bottom-Up: Chemical Vapor Deposition (CVD) (4 steps)

1.) Chemical gases pumped into vacuum chamber

2.) Heat/plasma breaks gas molecules -> individual atoms

3.) Atoms stick to a surface (substrate)

4.) Atoms link together -> ultra-thin layer

Bottom-Up: Self-Assembly (3 steps)

1.) Molecules w/ sticky ends put into a liquid or gas environment

2.) Molecules find each other

3.) Molecules snap together -> nanostructure

X-Ray Diffraction (XRD)

Non-destructive technique that uses X-rays to view the internal atomic structure

Light microscopy

Uses visible light to magnify samples

Electron microscopy (2 types/their functions)

1.) Scanning Electron Microscopy (SEM): Surface imaging

2.) Transmission Electron Microscopy (TEM): Internal structure

Scanning probe microscopy (2 types/their functions)

1.) Atomic force microscopy (AFM): Measures surface forces

2.) Scanning Tunnel Microscopy (STM): Maps electron density

UV-Vis

Measures light-absorption across UV-visible range

Photoluminescence

Emission of light after excitation

Energy dispersive spectrometry

Identifies elemental composition in electron microscopes

Mass spectrometry

Measures mass-to-charge ratios

Melting temperature

The temperature when a solid becomes a liquid

Density of nanomaterials

Mass per unit of volume of a material (decreases at nanoscale)

Hardness

A material's resistance to being scratched/dented

Strength

Material's ability to maintain shape under stress

Elastic modulus

A measure of the stiffness of a material

Adhesion

Force required to separate two forces

Wear

Material lost due to friction or contact

Scattering

Redirection of light by particles

Absorption

Conversion of light -> energy

Reflection

Light bouncing off of the surface

Refraction

Vending of light entering a material

Thermal conductivity

Ability of a material to conduct heat

Electrical conductivity

Movement of electrons through material

Dielectric properties

Material's ability to store electrical energy