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Concept
Polymère à séquence contrôlée
Résumé
A sequence-controlled polymer is a macromolecule, in which the sequence of monomers is controlled to some degree. This control can be absolute but not necessarily. In other words, a sequence-controlled polymer can be uniform (its dispersity Ð is equal to 1) or non-uniform (Ð>1). For example, an alternating copolymer synthesized by radical polymerization is a sequence-controlled polymer, even if it is also a non-uniform polymer, in which chains have different chain-lengths and slightly different compositions. A biopolymer (for example a protein) with a perfectly-defined primary structure is also a sequence-controlled polymer. However, in the case of uniform macromolecules, the term sequence-defined polymer can also be used.
With comparison to traditional polymers, the composition of sequence-controlled polymers can be precisely defined via chemical synthetic methods, such as multicomponent reactions, click reactions etc. Such tunable polymerizing manner endows sequence-controlled polymers with particular properties and thereby, sequence-controlled polymers-based applications (e.g. information storage, biomaterials, nanomaterials etc.) are developed.
In nature, DNA, RNA, proteins and other macromolecules can also be recognized as sequence-controlled polymers for their well-ordered structural skeletons. DNA, based on A-T, C-G base pairs, are formed in well-aligned sequences. Through precise sequences of DNA, 20 amino acids are able to generate sequential peptide chains with three-dimensional structures by virtue of transcription and translation process. These ordered sequences of different constituents endow organisms with complicated and diverse functions.
Traditional polymers are usually consist of one repeating unit or several repeating units, arranged in random sequences. Sequence-controlled polymers are composed of different repeating units, which are arranged in an ordered manner. In order to control the sequence, various kinds of synthetic methodologies are developed.
Source officielle
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