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Physical Chemistry

Monodisperse

Definition and meaning of Monodisperse in chemistry.

Monodisperse describes a collection of polymers, nanoparticles, or colloidal particles that all have the exact same size, mass, and shape. In a perfectly monodisperse sample, the distribution of molecular weights or particle sizes is completely uniform without any variation.

In more detail

In polymer chemistry, the dispersity index measures the overall breadth of the molecular weight distribution across a given sample. A truly monodisperse polymer has a dispersity index of exactly one. Achieving perfect monodispersity is incredibly difficult in synthetic chemistry, although biological macromolecules like specific folded proteins or genomic DNA strands are naturally monodisperse. Synthetic samples that possess a very narrow size distribution are often practically referred to as monodisperse for industrial and research applications, particularly in nanotechnology and drug delivery.

Key facts

FieldPhysical Chemistry
Dispersity IndexExactly 1.0
Primary ApplicationNanotechnology and polymer science
Example

A laboratory sample of identical gold nanoparticles, each measuring exactly 15 nanometers in diameter with no variance, would be considered a monodisperse colloid.

Frequently asked questions

How is monodispersity practically measured in synthetic polymers?

It is typically measured using analytical techniques like size exclusion chromatography, which calculates the strict ratio of weight average to number average molecular weight.

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