Janus cylinders

Figure 28 Illustration of the synthesis of core-cross-linked Janus cylinders. Reprinted from Liu, Y. Abetz, V. Muller, A. H. E. Macromolecules 2003, 36 (21), 7894-7898, with permission from ACS. ...

Fig. 30 Schematic phase morphologies of binary cylindrical bottle brushes Janus cylinder (left), Janus dumbbell (middle) and lamellar-like (right) morphologies. The red and blue domains are filled by the A and B monomers interfacial regions are green. From [99]...

Figure 30 shows the possible mesophase orderings that one might expect [99]. Early work [102,103] has focused on the possibility of microphase separation in the form of Janus cylinders [104], i.e., the cylinder splits into two halves, with a planar A-B interface (containing the cylinder axis, taken to be the z-axis henceforth). 

When a phase separation into a Janus cylinder structure occurs, e.g., where the upper half of the cylinder contains the B-rich phase and the lower half the A-rich phase, we have a planar AB interface (Fig. 32a) and the quantity that we wish to record is the vector normally oriented to this interface for any monomer of the backbone. Studying the orientational correlations of this vector will yield the desired information on possible fluctuations of interface orientation (Fig. 32b). Since the AB interface at nonzero temperature is not a sharp dividing surface, but rather has a finite width, a numerical characterization of the local orientation of this interface normal is difficult. Therefore, an essentially equivalent but numerically unambiguous characterization of this Janus cylinder-type ordering has been... 

Fig. 32 (a) Perfect phase separation of side chains in a binary (A, B) copolymer bottle bmsh with alternating grafting sequence ABAB... of side chains along the backbone into a Janus cylinder structure implies formation of an AB-interface phase (shaded) between the A-rich part (bottom) and the B-rich part (top) of the cylindrical brush. The local orientation of the interface can be characterized by a unit vector oriented normal to it (arrows), (b) At nonzero but low temperatures, phase separation will occur locally, but entropy will lead to long wavelength fluctuations of the... 

Possible shapes and forms of Janus particle (a) spherical Janus particle (b) and (c) two types of Janus cylinder (d)and (e) two types of Janus disks [93],... 

Fig. 2.2 Assemblies fonned in selective solvent conditions by multiblock copol3nners (from upper left to right) Janus spheres, core-shell spheres, raspberry-like spheres, Janus cylinders, core-shell cylinders, segmented cylinders, asymmetric (Janus) membrane vesicles, double-layer membrane vesicles, vesicles with hexagonally packed cylinders. Reproduced from [3] with permission from Elsevier...

Abstract Polyelectrolyte block copolymers form micelles and vesicles in aqueous solutions. Micelle formation and micellar structure depends on various parameters like block lengths, salt concentration, pH, and solvent quality. The synthesis and properties of more complicated block and micellar architectures such as triblock- and graft copolymers, Janus micelles, and core-shell cylinder brushes are reviewed as well. Investigations reveal details of the interactions of polyelectrolyte layers and electro-steric stabilization forces. 

Keywords Block copolymers ABC triblock copolymers Janus micelles Cylinder brushes Core-shell nanoparticles Graft copolymers Micelles Vesicles Copolyampholytes Polyelectrolyte block copolymers Aggregation... 

Figure 14.21 Formation of bi-colored Janus droplets in a planar microfluidic geometry. (a) Schematic of the channel and flow configuration (b) Convection in the head of the organic fluid cylinder induced by the external aqueous stream. Visualization was performed in another fluidic chip with similar geometry, into which a three-phase organic stream (a colorless isobornyl acrylate (IBA) stream in the center and two streams of black IBA on both sides) can be injected as the to-be-dispersed phase (c) Break-up of a hemispherically colored droplet in the co-flowing aqueous stream. The viscosities of black (rjb) and...

Janus-type polymer cylinders possessing a linear fixed core via selective cross-linking of a cylindrical bulk morphology of PS-b-PB-b-PMMA have been reported. In the bulk, the terpo-lymer formed a lamdlar stmcture of PS and PMMA with PB... 

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