nondiffusible

Nondiffusible refers to a property of a substance or phenomenon that prevents it from spreading or permeating through a medium or across a boundary. This lack of spreading is typically due to inherent characteristics of the substance itself, the nature of the barrier, or specific environmental conditions.

In chemistry, a nondiffusible substance is one that cannot readily pass through a semipermeable membrane or disperse into a surrounding solvent. This might be because the molecules are too large, too charged, or have very strong intermolecular forces that resist dissolution. For example, large polymer chains are often considered nondiffusible through certain membranes compared to smaller solvent molecules.

In physics, the term can describe a state where particles or energy are confined and do not undergo random motion and spreading. This is in contrast to diffusion, which is a fundamental process of movement driven by concentration gradients. A material that is nondiffusible would effectively act as a barrier to such spreading.

In biological contexts, nondiffusible molecules might be those that are unable to cross cell membranes or are retained within specific cellular compartments. This property is crucial for maintaining cellular organization and function, ensuring that certain molecules remain where they are needed and do not interfere with other processes. The concept of nondiffusibility is therefore important in understanding transport phenomena, material science, and biological processes.