Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

Graduate → Organic chemistry → Polymer chemistry ↓


Conducting polymer


Conducting polymers are a fascinating class of organic materials that have garnered significant interest in the fields of materials science and polymer chemistry. Unlike conventional polymers that are insulators, conducting polymers exhibit electrical conductivity, combining the mechanical flexibility of organic materials with the electrical properties of metals. This interesting combination of properties makes them suitable for a wide range of applications, including sensors, batteries, and electronic devices.

Introduction to polymers

To understand conductive polymers, one must first understand the basics of polymers. Polymers are large molecules composed of repeating structural units called monomers. These monomers are covalently bonded to form long chains. The most common examples of polymers include everyday plastics such as polyethylene, polyvinyl chloride (PVC), and polypropylene.

What makes polymers conductive?

The difference between insulating polymers and conducting polymers lies in the electronic structure. Insulating polymers have a band gap that prevents the free movement of electrons. Conducting polymers have a conjugated structure that allows electrons to move freely in the molecule, thus conducting electricity. This conjugation involves the overlap of π orbitals resulting in a delocalized system of electrons.

The principle of conductivity in polymers can be explained through a simple model of polyacetylene, the simplest form of conductive polymer:

-(C=C)n- Alternating single and double bonds represent conjugation.

Types of conductive polymers

A variety of conducting polymers have been synthesized, each with unique structural properties and conductivities. Some prominent examples include:

  • Polyaniline (PANI): It is doped to make it a conductor and can switch between conducting and non-conducting states due to changes in pH or the presence of oxidizing agents.
  • Polypyrrole (PPy): It is known for its good environmental stability and is often used in sensors and actuators.
  • Poly(3,4-ethylenedioxythiophene) (PEDOT): Exhibits high conductivity levels and is often used in flexible electronics.
  • Polyacetylene (PA): The first conductive polymer discovered, which helped lead to the discovery of an entire class.

Mechanism of conductivity

Conducting polymers achieve conductivity through a process called doping. Doping involves adding electrons (n-type) or removing electrons (p-type) to create charge in the polymer chain. This creation of charge carriers is what makes electrical conduction possible.

Doping process

In conducting polymers, doping can be represented as follows:

Neutral Polymer + Dopant → Charged Polymer + Counter-Ion Example: Polythiophene (neutral) conducts after doping with iodine.

The electronic configuration of polymers changes upon doping. Imagine using iodine as a dopant on polyacetylene, using the following simple reaction:

-(CH=CH)n- + I₂ → -(CH=CH)n

Structural requirements for conductivity

Not all polymers can be conductors unless they meet specific structural requirements. These include:

  • Conjugated system: Single and double bonds must be present in the backbone of the polymer to facilitate electron displacement.
  • Coplanarity: The polymer chain must be planar to allow π orbital overlap, which is important for electron movement.
  • Intermolecular interactions: Interactions between polymer chains can enhance conductivity by facilitating electron transfer across chains or by increasing overall crystallinity.

Visual representation

The structure of conducting polymers can be understood by visual diagrams:

Conjugated structure Dopants Delocalized electrons

Applications of conductive polymers

Conducting polymers are used in a variety of applications due to their flexibility, lightness, and customizable properties. Some of the major applications include:

  • Sensors: Conductive polymers respond to changes in the environment, making them ideal for chemical sensors that can detect gases and biomolecules.
  • Energy storage: They are used in batteries and supercapacitors, where their conduction properties are used to improve energy storage and recovery.
  • Displays: Conductive polymers are also used in OLED and other types of displays to provide a flexible substrate for emitting light.
  • Biomedical devices: Their biocompatibility and conductivity are used in bioelectronics to connect electronics with biological tissues.

Challenges and future prospects

Although conducting polymers have significant potential, challenges remain that need to be addressed for widespread applications:

  • Stability: Conductive polymers often suffer degradation when exposed to environmental conditions such as moisture and UV light.
  • Processability: Many conducting polymers are not easy to form into devices due to their poor solubility and inflexibility.
  • Cost: The synthesis of conducting polymers can be expensive, and cost-effective routes need to be developed for their commercial viability.

The focus of future research is on overcoming these challenges through the design of new polymers with improved stability, improved processability, and higher performance. The development of nanocomposites and the incorporation of functional groups are showing potential toward achieving these goals.

Summary

Conducting polymers present a bridge between traditional semiconductors and flexible, lightweight polymers that offer unique physical properties and new applications. As advances in their design, synthesis, and application continue, conducting polymers are poised to play an important role in materials science and polymer chemistry in the future.


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Conducting polymer

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