Patchy Micelles with a Crystalline Core: Self-Assembly Concepts, Properties, and Applications

Abstract

Crystallization-driven self-assembly (CDSA) of block copolymers bearing one crystallizable block has emerged to be a powerful and highly relevant method for the production of one- and two-dimensional micellar assemblies with controlled length, shape, and corona chemistries. This gives access to a multitude of potential applications, from hierarchical self-assembly to complex superstructures, catalysis, sensing, nanomedicine, nanoelectronics, and surface functionalization. Related to these applications, patchy crystalline-core micelles, with their unique, nanometer-sized, alternating corona segmentation, are highly interesting, as this feature provides striking advantages concerning interfacial activity, functionalization, and confinement effects. Hence, this review aims to provide an overview of the current state of the art with respect to self-assembly concepts, properties, and applications of patchy micelles with crystalline cores formed by CDSA. We have also included a more general discussion on the CDSA process and highlight block-type co-micelles as a special type of patchy micelle, due to similarities of the corona structure if the size of the blocks is well below 100 nm.

Functional Mesostructured Electrospun Polymer Nonwovens with Supramolecular Nanofibers

“…[21] Such nonwovens enable the removal of particulate matter from air with improved efficiency while at the same time a low pressure drop is maintained. [21] In a proof-of-concept we have also realized hierarchical superstructures composed of electrospun patchy polymer fibers with off-standing functional supramolecular fibers, utilizing a com-bination of crystallization-driven self-assembly (CDSA) [22][23][24][25] and molecular self-assembly. [26] The patchy polymer fibers consist of supporting polystyrene (PS) fibers that were decorated with patchy worm-like micelles (prepared by CDSA) via coaxial electrospinning.…”

Block Copolymers with Crystallizable Blocks: Synthesis, Self-Assembly and Applications

“…Considering the CDSA of block copolymers with crystallizable blocks in solution, this Special Issue includes two reviews focussing on the preparation and application of micelles with a patch-like microphase-separated (patchy) corona [50], as well as on glycine-based diblock copolypeptoids [51], respectively. Patchy micelles can be prepared by CDSA of triblock terpolymers with crystallizable middle blocks and two incompatible amorphous end blocks, or from mixtures of diblock copolymers with one common crystallizable block.…”

Janus Micelles by Crystallization-Driven Self-Assembly of an Amphiphilic, Double-Crystalline Triblock Terpolymer

“…45 CDSA was conducted in toluene, being a good solvent for the triblock terpolymer above the melting point of the PE middle block, resulting in the formation of worm-like micelles with a crystalline PE core. 14 Microdifferential scanning calorimetry (μ-DSC) measurements reveal a melting point for the PE block at T m = 46 °C and crystallization at T c = 28 °C, respectively (Figure 1A). This is in line with the behavior of other triblock terpolymers with crystalline PE middle blocks.…”

“…Janus particles and micelles have been intensively studied in the past with a strong focus on spherical structures, which is owed to the fact that cylindrical (1D) or platelet-like (2D) Janus structures are more difficult to realize. − Janus particles can be applied in a broad range of applications, for example, as highly efficient particulate surfactants for emulsion stabilization or compatibilization of polymer blends, as optical nanoprobes and biosensors, for self-propulsion, interfacial catalysis, and superhydrophobic and anti-ice coatings, and many more. 1D (cylindrical or worm-like) patchy micelles can be produced in an efficient manner employing crystallization-driven self-assembly (CDSA) and living CDSA, which allows control over length, length distribution, and corona chemistries. − There are two main concepts for the fabrication of 1D patchy micelles: (i) CDSA of linear triblock terpolymers with a crystallizable middle block, − or of μ-ABC miktoarm star terpolymers, and (ii) CDSA of a mixture of diblock copolymers bearing a common crystallizable block. − The patchy structure of the micellar corona gives rise to specific applications, for example, as templates for the regioselective incorporation of different nanoparticle types, in heterogeneous catalysis, , as compatibilizers in polymer blends or as highly efficient particulate surfactants, , and for the construction of hierarchical superstructures . So far, CDSA of triblock terpolymers with crystallizable middle blocks has always resulted in 1D micelles with a patchy corona.…”

“…The S 280 E 1250 EO 670 triblock terpolymer ( M n = 93.5 kg·mol –1 ) was synthesized by catalytic hydrogenation of a polystyrene- block -poly­(1,4-butadiene)- block -poly­(ethylene oxide) precursor (S 280 B 630 EO 640 , M n = 92.5 kg·mol –1 , Đ = 1.03, 88 mol% 1,4-butadiene units), prepared by sequential anionic polymerization (for details please see Supporting Information: Table S1, Figures S1 and S2) . CDSA was conducted in toluene, being a good solvent for the triblock terpolymer above the melting point of the PE middle block, resulting in the formation of worm-like micelles with a crystalline PE core. , Microdifferential scanning calorimetry (μ-DSC) measurements reveal a melting point for the PE block at T m = 46 °C and crystallization at T c = 28 °C, respectively (Figure A). This is in line with the behavior of other triblock terpolymers with crystalline PE middle blocks. , Interestingly, the crystallization temperatures ( T c ) of the PEO block ( T c1 = 11 °C and T c2 = 0 °C) are significantly higher compared to those observed for the S 280 B 630 EO 640 precursor ( T c = −13 °C, Figure S3A) and neat PEO in toluene at identical PEO concentration ( T c = −11 °C, Figure S3B).…”