Hybrid block copolymers experimental

In the past two years, a number of new approaches have been reported for obtaining controlled NCA polymerizations. These approaches share a common theme in that they are all improvements on the use of classical primary amine polymerization initiators. This approach is attractive since primary amines are readily available and since the initiator does not need to be removed from the reaction after polymerization. In fact, if the polymerization proceeds without any chain breaking reactions, the amine initiator becomes the C-terminal polypeptide end-group. In this manner, there is potential to form chain-end-functionahzed polypeptides or even hybrid block copolymers if the amine is a macroinitiator. The challenge in this approach is to overcome the numerous side-reactions of these systems without the luxury of a large number of experimental parameters to adjust. 

MatejicekP, Humpolickova J, Prochazka K, Tuzar Z, SpirkovaM, Hof M, Webber SE (2003) Hybrid block copolymer micelles with partly hydrophobically modified polyelectrolyte shells in polar and aqueous media experimental study using fluorescence correlation spectroscopy, time-resolved fluorescence, light scattering, and atomic force microscopy. J Phys Chem B 107(32) 8232-8240. doi 10.1021/jp022221s... 

Time-resolved in situ Small Angle Neutron Scattering (SANS) investigations have provided direct experimental evidence for the initial steps in the formation of the SBA-15 mesoporous material, prepared using the non-ionic tri-block copolymer Pluronic 123 and TEOS as silica precursor. Upon time, three steps take place during the cooperative self-assembly of the Pluronic micelles and the silica species. First, the hydrolysis of TEOS is completed, without modifications of the Pluronic spherical micelles. Then, when silica species begin to interact with the micelles, a transformation from spherical to cylindrical micelles takes place before the precipitation of the ordered SBA-15 material. Lastly, the precipitation occurs and hybrid cylindrical micelles assemble into the two-dimensional hexagonal structure of SBA-15. 

Figure 7.14 Experimental and simulated morphologies of block copolymer/nanoparticle systems at two different particle volume fractions (10 and 35 vol.%). Simulations were performed using a hybrid SCFT method [113],...

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