Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Polymer Collapse: Covolume and Free Energy

In course

PHYS-441: Statistical physics of biomacromolecules

Biological macromolecules such as DNA, RNA, proteins and cytoskeletal filaments are polymers. As such, they share a set of properties that are common to any polymer, which are the focus of this course. Details about the protein folding problem will be cove ...

Description

This lecture covers the concept of polymer collapse, focusing on the covolume and free energy involved in the process. The instructor explains the non-ideal gas behavior, the repulsive and attractive interactions, and the thermodynamic favorability of the collapse. The discussion also includes the Flory Free-energy equation, the role of the covolume 'Jo', and the implications of non-ideal gas behavior in polymer systems.

Official source

Ontological neighbourhood

Physics

Thermodynamics: Statistical mechanics

Related concepts (32)

Helmholtz free energy

In thermodynamics, the Helmholtz free energy (or Helmholtz energy) is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature (isothermal). The change in the Helmholtz energy during a process is equal to the maximum amount of work that the system can perform in a thermodynamic process in which temperature is held constant. At constant temperature, the Helmholtz free energy is minimized at equilibrium.

Gibbs free energy

In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol ) is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure-volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure. It also provides a necessary condition for processes such as chemical reactions that may occur under these conditions. The Gibbs free energy is expressed as where p is pressure, T is the temperature, U is the internal energy, V is volume, H is the enthalpy, and S is the entropy.

Thermodynamic free energy

In thermodynamics, the thermodynamic free energy is one of the state functions of a thermodynamic system (the others being internal energy, enthalpy, entropy, etc.). The change in the free energy is the maximum amount of work that the system can perform in a process at constant temperature, and its sign indicates whether the process is thermodynamically favorable or forbidden. Since free energy usually contains potential energy, it is not absolute but depends on the choice of a zero point.

Ideal gas

An ideal gas is a theoretical gas composed of many randomly moving point particles that are not subject to interparticle interactions. The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation of state, and is amenable to analysis under statistical mechanics. The requirement of zero interaction can often be relaxed if, for example, the interaction is perfectly elastic or regarded as point-like collisions.

Intermolecular force

An intermolecular force (IMF) (or secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighbouring particles, e.g. atoms or ions. Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing electron pairs between atoms, is much stronger than the forces present between neighboring molecules.

Related lectures (44)

Energy Minimization in Biological Systems: Equilibrium Models

Covers energy minimization models in biological systems, focusing on equilibrium and the roles of entropy and hydrophobicity.

Thermodynamics: Exploring Thermodynamic Potentials and Equilibrium States

Covers thermodynamic potentials and their role in system equilibrium with reservoirs.

Chemistry: Atomic Structure and Thermodynamics

Covers atomic structure, thermodynamics, material properties, and ideal gas law.

Chemical Thermodynamics: Principles and Applications

Provides an overview of chemical thermodynamics, focusing on potential, reaction kinetics, and the relationship between thermodynamic properties and chemical reactions.

Thermodynamics: Enthalpy and Energy Transformations