Module 5: Functional Materials Quiz

Module 5: Functional Materials

• Functional materials module covers 4 hours of study.
• This module includes polymers (ABS and BAKELITE), their synthesis and applications.
• It also includes conducting polymers (polyacetylene), and the effect of doping.
• Nanomaterials, including introduction, bulk vs nano (gold), top-down and bottom-up synthesis approaches are also part of the module.
• An e-book link for nanomaterials is provided: https://drive.google.com/file/d/18GiueZtfwNd5atOi5V8sijg9oqR-LvjM/view?usp=sharing

Polymers

• Polymers are formed by the joining of many smaller units (mers).
• The name "polymer" hints at how these units are assembled.
• The term "plastics" describes the molding property of polymers.

Introduction to Polymers

• Polymers are large molecules (macromolecules).
• They form from repeated linking of smaller molecules known as monomers.
• An example of a polymer is polyethylene, formed from ethylene monomers.

Polymer Terminology

• A mer is a single unit within a polymer chain.
• Monomer: Refers to one unit.
• Dimer: Refers to two units.
• Trimer: Refers to three units.
• Tetramer: Refers to four units.
• Polymer: Refers to many units.

What is a Polymer?

• Berthelot first noted the transformation of styrene into a polymer.
• Hermann Staudinger coined the modern concept of polymers - the sense in use today.
• This concept led to the Nobel Prize in 1953.

Introduction to Nanomaterials

• A nanoparticle is small, typically a few nanometers wide, containing thousands of atoms, and is identified by its tiny size
• One nanometre is a millionth of a millimeter or 10⁻⁹ meters.

Size and Shape of Nanoparticles

• Size and shape of nanoparticles affect their colour.
• Visible light is scattered rather than absorbed.
• The distance between particles affects colour.

Surface Plasmons

• Surface plasmons are oscillations of conduction electrons when electromagnetic radiation interacts with metal nanoparticles.
• They are studied using the UV-Visible spectrum of the nanoparticles.

Applications of Surface Plasmon Resonance

• Diagnostics of biomolecular interactions.
• Simulations using Mie theory help to determine the size of nanoparticles.

Categories of Nanomaterials

• Nanomaterials are classified into different categories, including carbon-based, inorganic, and polymeric materials.

Applications of Nanomaterials

• Nanomaterials have applications in biomedical fields, electronics, biocompatible coatings, and more.

Top-Down and Bottom-Up Synthesis

• Top-down is a technique for extracting nanomaterials from larger ones.
• Examples include High-energy ball milling/Machining, Chemical Oxidation, and more.
• Bottom-up synthesizes nanomaterials from atoms or molecules.
• Examples include Gas Condensation and more.

Fabrication Techniques and Considerations

• Techniques for preparing nanoparticles must result in identical size and shape, consistent chemical composition and crystal structure, and dispersed particles, not agglomerated.

Conducting Polymers

• Polymers, especially those with conjugated π-bonds, display increased conductivity when doped with conductive materials.
• However, their poor mechanical strength limits their applications.
• Blending polymers allows combining desired properties.

Different Types of Conducting Polymers

• Intrinsically conducting polymers, Doped Conducting polymers, and Extrinsically conducting polymers.
• Factors that affect conductivity include charge carrier density, mobility, direction, doping, and temperature are crucial to understand.

p- and n-Doping

• p-doping increases conductivity by oxidation (removing electrons), typically with Lewis acids.
• n-doping increases conductivity by reduction (adding electrons), commonly with Lewis bases.

Conductivity Mechanism in Polyacetylene

• Conductivity in polyacetylene is through intersoliton hopping.
• Solitons are charged or neutral defects that propagate down the polymer chain, reducing energy barriers.

Extrinsically Conducting Polymers

• Extrinsic conductivity is caused by externally added materials.
• Two types are conductive element-filled polymers and blended polymers (blends of regular and conducting polymers).

Applications of Conducting Polymers

• Conducting polymers have applications in fibres, electroluminescent devices, displays, printed circuit boards, electrochromic windows, and more.

Properties and Applications of Nanoparticles

• Different properties arise at the nanoscale.
• Gold nanoparticles can yield different colours based on their size and shape.

Surface Area to Volume Ratio

• Increasing surface area relative to volume affects the reactivity of materials, which can result in better catalysis.

Wet Chemical Synthesis of Nanomaterials

• A method involving precursor solutions, the formation of a gel, drying, and dehydration produces nanomaterials.

Sol-gel Process Considerations

• The solvent determines the type of product produced. This process results in a monolithic product.

Advantages of Nanomaterials Synthesis

• The bottom-up synthesis method allows the creation of monosized nanoparticles, and allows synthesis of inorganic materials at low temperatures.

Disadvantages of Nanomaterials Synthesis

• Controlling particle growth and preventing agglomeration, complete reactant removal, and slow production rates are challenges.

Considerations for Choice of Nanotechnology Synthesis Methods

• Top-down and bottom-up methods, have advantages and disadvantages, and choice depends on the desired outcomes and materials.