Hybrid block copolymers water

To take a closer look at the area per molecule in the condensed phase of the diblock monolayers, the x-axis of Fig. 4.14a is expanded and shown in Fig. 4.14c. The extrapolated value of the area per molecule and the theoretically expected value for the area are listed in Table 4.5. To calculate the theoretically expected area for the hybrid block copolymers in the condensed phase, it is assumed that the stearate end groups are extended into the air perpendicular to the air-water interface as shown schematically in Fig. 4.14d. This assumption is based on the behavior of pure stearic acid, which forms ordered monolayers with the alkyl chains oriented perpendicular to the air-water interface. The area per molecule for stearic acid with this orientation is 20 A2, [113] Here, the theoretically expected area was calculated by multiplying the area per stearate molecule (20 A2) with the number of stearate groups present at the ends of the dendrimer block. PEO(2k)-S having no dendrimer block but a single... 

The transition from hybrid block copolymers with a homopeptide block toward those with sequence-defined peptide segments enriches the self-assembly behavior strongly. Ayers et smdied water-soluble block copolymers composed of a PEO block and a peptide block with comb architecture, which was obtained by the controlled polymerization of oligopeptide... 

Exchange of unimers between two different types of block copolymer micelles has often been referred to as hybridization. This situation is more complex than for the case described above because thermodynamic parameters now come into play in addition to the kinetic ones. A typical example of such hybridization is related to the mixing of micelles formed by two different copolymers of the same chemical nature but with different composition and/or length for the constituent blocks. Tuzar et al. [41] studied the mixing of PS-PMAA micelles with different sizes in water-dioxane mixtures by sedimentation velocity measurements. These authors concluded that the different chains were mixing with time, the driving force being to reach the maximum entropy. 

The solution properties of hybrid-linear dendritic polyether copolymers are investigated by SEC with coupled viscometric detection from the same authors [12]. The results obtained show that the block copolymers are able to form monomolecular and multimole-cular micelles depending on the dendrimer generation and the concentration in methanol-water (good solvent for the linear blocks). 

PPE Block Copolymers Jacketed PPEs Water-Soluble PPEs Metu-PPEs Linear and Crossed PPE-PPV Hybrids Organometallic PAEs Thiophene-Containing PAEs Nitrogen Heterocycle-Containing PAEs... 

Block copolymers are useful in many applications where a number of different polymers are connected together to yield a material with hybrid properties. For example, thermoplastic elastomers are block copolymers containing a rubbery matrix (polybutadiene or polyisoprene) containing glassy hard domains (often polystyrene). The block copolymer, a kind of polymer alloy, behaves as a rubber at ambient conditions, but can be molded at high temperatures because of the presence of the glassy domains that act as physical cross-links. In solution, attachment of a water-soluble polymer to an insoluble polymer leads to the formation of micelles in amphiphilic block copolymers. The presence of micelles leads to structural and flow characteristics of the polymer in solution, that differ from either parent polymer. 

---