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The realistic synthesis of these well-defined complex amphiphilic macromolecules having brush-like architecture is possible based on synthetic approaches and ‘tricks’ we have developed in Dr. Hogen-Esch ‘s group. Anionic polymerization from the initiator site I is the key step to prepare first ‘special’ hydrophobic block of controllable degree of polymerization and polydispersity. Coupling of polymer anions with bifunctional electrophiles (9,10-BCMA, BBMA, phenathrene or naphthalene containing as well) at the conditions developed by our group gives quantitative incorporation of fluorescent labels (FL). Deprotection of special groups on hydrophobic block 1 produces sites on each pendent group capable of initiation of the next block 2. At this stage there is no heteroatoms present in the macromolecule. Anionic polymerization of the second block 2 produces in controlled manner PMMA, PtBuMA or PEO brushes which can be terminated with properly chosen electrophiles to give fluorescent labels, protons or alkyls at the end of each brush chain. Hydrolysis of PtBuMA produces hydrophilic brushes of PMAA making these systems interesting objects of polymer self-assembly studies. The sites of initiator I may also be the point of growing the third block 3, which can be either hydrophobic or hydrophilic. Possible techniques include anionic polymerization of EO or ATRP of MMA and tBuMA similar to that reported by Dr. M.A. Winnik. The polymers proposed here possess well-defined structure, controlled molecular weight and placement of fluorescent labels. These polymers can be used to test self-assembly in solvents of different polarity or selectivity to different blocks of the molecule. Also, studies on polymer interfaces can be performed, as well as energy transfer and light harvesting potential of these amphiphilic macromolecules can be evaluated. The fluorescent labels can be selectively placed inside of the same brush, or the interactions between different types of brushes (2 hydrophobic, or 1 hydrophobic and 1 hydrophilic) can be done by placing different chromophores in the middle of different types of brushes giving the possibility of energy transfer monitoring. The macromolecules without fluorescent labels are interesting objects themselves, as PMMA and PEO are commercially important polymers. Formation of ordered patterns of nanometer scale can be envisioned on surfaces from proper solvent where these polymers can self-assembly and form micelles.
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