Creating modern materials Flashcards
(17 cards)
SMART materials
A class of materials with engineered properties that respond to external stimuli like light, temperature, or pressure.
Chemical Synthesis
- Chemically modifying existing materials at a molecular level. For instance, photochromic sunglasses use light-sensitive molecules that change shape when exposed to light, darkening the lenses.
Composite Fabrication
- Combining two or more different materials to create SMART properties. Shape-memory alloys contain a specific crystal structure that allows them to “remember” their original shape when heated, even after being deformed.
Nanotechnology
- The precise manipulation of materials at the atomic and molecular level. This opens doors for creating new SMART materials with highly specific properties.
What are the two main types of foams?
- Open-cell foams
- Closed-cell foams
Open-cell foams
These have interconnected pores throughout the material, allowing air or liquid to pass through.
Creation processes of open-cell foams
- Chemical foaming: Adding blowing agents to a liquid polymer that decompose upon heating, releasing gas and creating bubbles in the solidifying material.
- Mechanical foaming: Whipping air or gas into a liquid polymer to create a dispersion, which then solidifies into foam.
Closed-cell foams
These have individual gas bubbles trapped within the material.
Creation process of closed-cell foams
- Extrusion: Forcing molten plastic mixed with a blowing agent through a die, creating a continuous foam sheet.
Where do natural rubbers come from?
Natural rubber comes from latex, a milky fluid tapped from rubber trees.
Where do synthetic rubbers come from?
Synthetic rubbers are created through polymerization, a process where monomers (small molecules) link together to form long chains (polymers). These polymers are then compounded with various additives to achieve desired properties like strength, elasticity, and resistance to wear and tear.
Wood-Based Composites
- Engineered materials made from wood particles bonded with adhesives.
Examples of wood-based composites
- MDF
- Plywood
- Chipboard
- Blockboard
Metalized Materials
Metallization refers to applying a thin layer of metal to a surface.
Physical Vapor Deposition (PVD)
Metals are vaporized in a vacuum chamber and condense onto the target surface. This is used for delicate applications like electronics.
Electroplating
An electric current is used to deposit metal ions from a solution onto a conductive surface. This is a common method for chrome plating car parts.
Sputtering
A high-energy beam dislodges atoms from a metal target, which then coat the desired surface. This is used for applying thin metal films in microelectronics.
