Copolymers, hydrophobic hydrophilic polymer grafted

Block copolymers that consist of hydrophilic and hydrophobic segments are typical amphiphilic polymers, a variety of which have been synthesized by living cationic polymerization. Figure 9 schematically illustrates the structures of some of these amphiphilic polymers thus far obtained though the examples therein are based on poly(vinyl ether) segments, any other appropriate segments may be incorporated. As seen in the illustrations, macromolecular amphiphiles are not necessarily linear AB- and ABA-type block copolymers but may be graft, multiarmed, and network polymers, where the basic components are amphiphilic block copolymers. 

Emulsion polymerization has become an important process for the production of a large number of industrial polymers in the form of polymer colloids or latexes. They are the base of adhesives, paints and especially of waterborne coatings. An interest has been developed in recent years in emulsion polymerization systems in which the classical low molecular weight surfactaints are replaced by polymeric surfactants, either hydrophilic-hydrophobic block and graft copolymers (1-4) or functionalized oligomers (5). 

Uchida T, Serizawa T, Ise H, et al. (2001). Graft copolymer having hydrophobic backbone and hydrophilic branches. 33. Interaction of hepatocytes and polystyrene nanospheres having lactose-immobilized hydrophilic polymers on their surfaces. Biomacromol. 2 1343-1346. 

Liu L, Xu X et al (2009) Synthesis and self-assembly of chitosan-based copolymer with a pair of hydrophobic/hydrophilic grafts of polycaprolactone and poly(ethylene glycol). Carbohydr Polym 75 401 07... 

Hydrophilic/hydrophobic force balance of polymers may be varied by incorporation of a hydrophilic polymer in a bulk of a hydrophobic polymer (grafting of a hydrophilic monomer would be such a case). Also different block copolymers and polymer alloys are prepared with the aim to ensure the desired properties of the polymer. All these procedures alter the nature of the polymer, changing the magnitude of its long and short range forces. 

Amphiphilic/associating vater-soluble polymers, in particular block copolymers and hydrophobically modified vater-soluble polymers, have been studied extensively during the last decade and are vell understood [50, 51]. For graft copolymers that are hydrophobically modified vater-soluble polymers, vhich are common as thickeners and dispersants, the self-assembly is very different than for block copolymers. For such graft copolymers there is a strong opposing force due to the hydrophilic polymer backbone. In particular, due to the entropic penalty in folding the polymer chain, only small discrete hydrophobic micro-domains ( micelles ) are formed. 

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