Copolymers solution self-assembly

Roy, D., Cambre, J.N., and Sumerlin, B.S. (2009) Triply-responsive boronic acid block copolymers solution self-assembly induced by changes in temperature, pH, or sugar concentration. Chem. Commun., 16, 2106-2108. 

Hamley IW, Ansari A, Castelletto V et al (2005) Solution self-assembly of hybrid block copolymers containing poly(ethylene glycol) and amphiphilic beta-strand peptide sequences. 

Zhang L, Bartels C, Yu Y, Shen H, Eisenberg A. Mesosized crystal-like structure of hexagon-ally packed hollow hoops by solution self-assembly of diblock copolymers. Phys Rev Lett 1997 79 5034-5037. 

The cosolvent method, also known as solvent injection method permits vesicle formation for glassy or crystalline block copolymers. As a rule, the amphiphilic copolymer is dissolved in an appropriate organic solvent or solvent mixture, the role of which is to lower the Tg below room temperature next the solution is added dropwise to an aqueous buffer under vigorous stirring. Originally this method has been employed for PS-PAA and PS-PEO copolymers that self-assembled in vesicular structures by adding water to DMF or dioxane polymer solution [61,105] and then further applied to many other polymer systems [165],... 

Brown MD, Gray AI, Tetley L, Santovena A, Rene J, Schatzlein AG, Uchegbu IF (2003) In vitro and in vivo gene transfer with poly(amino add) vesicles. J Contr Release 93(2) 193-211 Zhang L, Bartels C, Yu Y, Shen H, Eisenbeig A (1997) Mesosized crystal-Uke stmcture of hexagonally packed hollow hoops by solution self-assembly of diblock copolymers. Phys Rev Lett 79 5034-5037... 

The self-assembly of polymer chains in aqueous solution can also take place due to a micellization process. Amphiphilic block copolymers (e.g., diblock or triblock copolymers) can self-assemble in aqueous solution and further be cross-linked... 

Consider the complexity involved in modeling steric stabilization with a diblock copolymer. The reservoir bulk solution of copolymer is usually dilute (<1 wt % polymer) and the copolymer and solvent equilibrate between the bulk and surface regions. However, as solvent quality is decreased to the LCST phase boundary, the bulk solution will also separate into polymer-rich and polymer-lean phases. In addition, many diblock copolymers form self-assembled aggregates such as micelles and lamellae, if the concentration is above the critical micelle concentration. Thus, stabilizer can partition among up to four phases as solvent quality or polymer concentration is changed. The unique density dependence of supercritical fluids adds another dimension to the complex phase behavior possible. In the theoretical studies discussed below, surfactant adsorption energy, solubility, and concentration are chosen carefully to avoid micelle formation or bulk phase separation, in order to focus primarily on adsorption and colloid stability. 

A diblock copolymer made from a soluble and a nonsoluble monomer has an amphiphilic character. The nonsoluble blocks aggregate and the soluble parts dangle out in the solution. In an aqueous environment, such block copolymers thus self-assemble to form polymer micelles that consist of a nonaqueous densely... 

Block copolymers spontaneously self-assemble into interesting microstructures in dilute solution, in the bulk, and in the presence of surfaces and interfaces. Monte Carlo simulations of coarse-grained block copolymers on simple lattices have been used in the last few years to investigate the generic properties of block copolymers [1,2]. Since the coarse-grained chains are not atomistic, it is diflBcult to make a one-to-one comparison of a simulation and a spe-... 

Solution self-assembly nsnally involves an amphiphilic multiblock copolymer in which the blocks display different solubility properties. The self-assembly process involves the association of an insolnble segment or segment(s) of the copolymer chain, when the copolymer is placed in a solvent system that solvates only a portion of the overall chain, at concentrations, at or above the critical micelle concentration (cmc). The cmc is a critical parameter in determining the stability of the assembly and is often significantly lower for block copolymer assemblies than surfactant assemblies. A simple solution thermodynamic measure of aggregate stability or cmc can be expressed in terms of n, the degree of polymerization, by (1). 

Micellar-drug formulation is another delivery system based on hydrophilic-hydrophobic block copolymers that self-assemble in aqueous solution into micellar particles with a hydrophobic core and a hydrophilic shell. NK012 is an example of micellar formulation of SN 38 (11) developed by Nippon Kayaku which is in Phase 1 clinical trial [287-289]. 

The stractural and functional complexity of biomembranes has ehal-lenged researehers to develop simpler artificial models to mimie their properties. Amphiphilic block copolymers are of particular interest, beeause of the dual environmental affinity that is associated with covalently bound hydrophobie and hydrophilic blocks. These strive to minimize their eontaet, and therefore drive self-assembly into assemblies with different arehi-teetures. Based on their chemical specificity, as for example the hydrophilie-to hydrophobie ratio, amphiphilic block copolymers can self-assemble in dilute aqueous solutions into micelles, vesicles, tubes, wire-like structures, nanopartieles, or planar membranes at water-air interfaces. Synthetic membranes have greater mechanical stability than phospholipids because of the higher moleeular weight (Mw) of amphiphilic block copolymers, and thus are thicker and stiffer than lipid bilayers. 

The conttolled bottom-up fabrication of nanomaterials with well-defined but complex architectures [167-173] can be achieved by preparing the samples as colloidal stable entities. Cylindrical micelles [174, 175] obtained from the solution self-assembly of block copolymers have found use as additives for the enhancement of the toughness of epoxy resins [176], as templates for the mineralization of hydroxyapatite [177], the formation of metal nanoparticles [178-181], as... 

De, P., Gondi, S. R. and Sumerlin, B. S. (2008) Folate-conjugated thermoresponsive block copolymers Highly efficient conjugation and solution self-assembly. Biomacromolecules, 9, 1064-70. 

Synthesis and Solution Self-Assembly of Polyferrocene-Based AB Diblock and ABC Triblock Copolymers... 

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