Hydrophilic functional groups, synthesis

Synthesis of Biodegradable Copolymers with Pendant Hydrophilic Functional Groups... 

Proteins derive their powerful and diverse capacity for molecular recognition and catalysis from their ability to fold into defined secondary and tertiary structures and display specific functional groups at precise locations in space. Functional protein domains are typically 50-200 residues in length and utilize a specific sequence of side chains to encode folded structures that have a compact hydrophobic core and a hydrophilic surface. Mimicry of protein structure and function by non-natural ohgomers such as peptoids wiU not only require the synthesis of >50mers with a variety of side chains, but wiU also require these non-natural sequences to adopt, in water, tertiary structures that are rich in secondary structure. 

Each step in dendrimer synthesis occurs independent of the other steps therefore, a dendrimer can take on the characteristics defined by the chemical properties of the monomers used to construct it. Dendrimers thus can have almost limitless properties depending on the methods and materials used for their synthesis. Characteristics can include hydrophilic or hydrophobic regions, the presence of functional groups or reactive groups, metal chelating properties, core/shell dissimilarity, electrical conductivity, hemispherical divergence, biospecific affinity, photoactivity, or the dendrimers can be selectively cleavable at particular points within their structure. 

Generally, humic substances are defined as condensed polymers of aromatic and aliphatic compounds produced by decomposition of plant and animal residues and by microbial synthesis. They are amorphous, dark-colored, and hydrophilic, with a wide range in molecular weight from a few hundreds to several thousands. Furthermore, humic substances contain a large number of nonidentical functional groups, with different pKa values, and are partitioned into three main fractions based upon their solubility behavior (Fig. 3.16) (Evangelou, 1995b) ... 

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