Amphiphiles I have known

Polyfluoroalkyl Chain-Based Assemblies for Biomimetic Catalysis

Amphiphobic fluoroalkyl chains are exploited for creating robust and diverse self-assembled biomimetic catalysts. Long terminal perfluoroalkyl chains (Cn F2n+1 with n=6, 8, and 10) linked with a short perhydroalkyl chains (Cm H2m with m=2 and 3) were used to synthesize several 1,4,7-triazacyclononane (TACN) derivatives, Cn F2n+1 -Cm H2m -TACN. In the presence of an equimolar amount of Zn2+ ions that coordinate the TACN moiety and drive the self-assembly into micelle-like aggregates, the critical aggregation concentration of polyfluorinated Cn F2n+1 -Cm H2m -TACN⋅Zn2+ was lowered by ∼1 order of magnitude compared to the traditional perhyroalkyl counterpart with identical carbon number of alkyl chain. When 2'-hydroxypropyl-4-nitrophenyl phosphate was used as the model phosphate substrate, polyfluorinated Cn F2n+1 -Cm H2m -TACN⋅Zn2+ assemblies showed higher affinity and catalytic activity, compared to its perhyroalkyl chain-based counterpart. Coarse-grained molecular dynamic simulations have been introduced to explore the supramolecular assembly of polyfluoroalkyl chains in the presence of Zn2+ ions and to better understand their enhanced catalytic activity.

Remembrances of self-assemblies past

Research on four types of self-assemblies (micelles, coacervates, gels, and vesicles) is discussed via a particular investigative methodology (in order of appearance): kinetics, dynamic NMR, PGSE-NMR, double-(13)C labeling, molecular dynamics computations, phase diagrams, cryo-HRSEM, rheology, light/electron microscopy, electrophoretic mobility, electroformation, confocal microscopy, and calorimetry. The emphasis here is on how a given method, each in its own special way, illuminates a complex system.

Polymerization-like multilevel hierarchical self-assembly of polymer vesicles into macroscopic superstructures with controlled complexity

We demonstrate a high-leveled hierarchical self-assembly process into fractal structures. Two hyperbranched multiarm copolymers are first coassembled into binary isotropic vesicles in the primary self-assembly. Then, these primary vesicles are in situ endowed with anisotropic hydrophobic "binding sites" through a pH-induced lateral microphase separation, undergoing an isotropic-anisotropic transition. Subsequently, the anisotropic vesicles further assemble together through the specific self-recognition between the binding sites into linear, branched, cyclization, and network-like vesicle chains. Furthermore, the obtained vesicle chains can transform into linear, branched, ring-like, and network tubes through successive vesicle fusion. Such a hierarchical process is pH-triggered and well-controlled by adjusting the vesicle compositions and is coined as "polymerization-like" self-assembly due to the striking analogy between the vesicle association model and polymerization process.