Dendrimers

Whereas typical polymers run like linear chains, dendrimers are tree-like polymers. They branch out from a central core, exhibiting a dense surface surrounding a relatively hollow core. They are a series of chemical shells built on a small core molecule.

Dendrimers

Dendrimers are a special class of polymers. A polymer is a huge molecule made up of tens of thousands of repeating units called monomers (or mers). The prefix mono stands for “single” and poly stands for “many”. A monomer is a simple organic molecule that reacts with other monomers to form a large polymer. Polymers are ubiquitous in our lives, they represent a large class of natural and synthetic materials that are used to make textiles, rubber, tires, stockings, sporting goods, and food packaging.  

Whereas typical polymers are composed of linear chains, dendrimers are branching polymers that assume forms that are tree-like.  They spread out from a sparse, central core and end with a relatively dense surface that is exposed to the surroundings. In some ways, their structure can be described as molecular shells that surround a small core molecule. The size is typically not more than 15 nanometers but the molecular weight is large.  

Since the central core of a dendrimer is sparsely occupied, it can act as a cavity or a pouch which can be used to trap or store “guest molecules.” Consequently, the interior and the core of dendrimers can be tailored for different applications. Dendrimers are being considered for use in a variety of biomedical applications where the guest molecules can be pharmaceuticals, candidates for gene therapy or cancer therapy, or antimicrobial and antiviral agents.  Another are of interest is the synthesis of organic light emitting polymers that can be used to make organic light emitting diodes (OLEDs).

Nominal PbSe nano-islands on PbTe: grown by MBE, analyzed by AFM and TEM (Peter Moeck, Mukes Kapilashrami, Jeahuck Lee, James E. Morris, Nigel D. Browning, and Patrick J. McCann, ISSE 2004)

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