Customizing polyelectrolytes through hydrophobic grafting.

This up-to-date review describes the design, fabrication approaches, properties and applications that have been employed in the field of hydrophobically decorated polyelectrolytes (HD-PEs), used as functionalized building blocks for speciality materials with tuneable features. These include, in particular, synthetic strategies for modification/hydrophobization of polyelectrolytes, self-organization of HD-PEs in aqueous systems, adsorption phenomena and applications in the field of surface chemistry. Rationally engineered HD-PEs can be achieved via either step-growth copolymerization of different reactive end groups of monomers, followed by appropriate post-synthesis treatment or as a result of decoration of a given polymer backbone with hydrophobic side groups. The influence of HD-PEs' chemical structure on their self-assembling and interfacial properties is dependent on the overall hydrophobicity, i.e. length, number and type of side chains stretched out to charged segment, number, type and strength of ionizable groups. We also conclude that the linking entity structure (ester, secondary amide, etc.) between the hydrophobic side chain and the charged polyelectrolyte backbone in the tailor-made HD-PEs plays a crucial role in self-aggregation behaviour in water and at interfaces. The examples of the unique ability of HD-PEs to adsorb at hydrophilic and hydrophobic interfaces is discussed considering the effect of the self-aggregation on the interfacial properties.