Fabrication of functional nano‐objects via self‐assembly of nanostructured hybrid materials

Abstract

A simple route to fabricate functional nano-objects via self-assembly of block copolymer-based hybrid materials is described. In water-toluene mixtures, spheres, rod-like morphologies, and ring-like morphologies as well as vesicles of metal loaded block copolymers micelles are fabricated. The concept is generic to realize different functionalities by incorporating various inorganic components (Au, Ag, Pt, Co…) into the block copolymer matrix. A mechanism describing the formation of micellar aggregates with different morphologies is presented based on a simple force balance approach. Moreover, the composition of the solvent mixture is modified to gain control over the morphology of micellar aggregates. It was found that swelling of the micelle core with a selective cosolvent is the driving force to induce morphology transitions from spherical to rod-and ring-like structures as well as vesicles. These nano-objects can be further used as building blocks to construct well-defined structures via self-assembly in spin coated thin films.

Effects of Second Solvents on the Interaction of Polymeric Micelles in Aqueous Solution

“…As mentioned in the introduction section, PS-b-P4VP micelles dissolved in toluene were transformed into ring or rod conformation by adding core-compatible compound. [8][9] And similar result was found in PS-b-PEO micelle in DMFwater mixed solvent. 10 Therefore phase transformation of micelle requires both second solvent and larger core block compared to corona.…”

“…For examples, spherical micelle of polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) in toluene transformed into ring conformation by adding water and the morphology further changed to rod-like aggregates by adding the inorganic precursor. [8][9] Similar behaviors have been found in PS-b-PEO soluble in DMF-water mixed solvent, where the micelle morphology changed from spheres to wormlike cylinders as water content increased. 10 Here it is believed that the morphological transition of the micelles is accompanied by micellar interaction changing from repulsive to attractive by adding second solvents, which happens more plausibly when the micelle has larger core block compared to the corona.…”

Effect of substrate on particle arrangement in arrays formed by self-assembly of polymer grafted nanoparticles

“…The emergence of novel electronic, optical and magnetic properties in ordered two-dimensional (2D) nanoparticle ensembles, due to collective dipolar interactions of surface plasmons or excitons or magnetic moments, [1][2][3][4][5] and the appeal of cost-effective nanostructure fabrication [6][7][8][9] have motivated intense research efforts into selfassembly based methods for fabricating 2D nanoparticle superlattices. Self-assembly of ligand protected nanoparticles [10][11][12] or the use of diblock copolymer micelles as templates [13][14][15] are the most preferred routes for fabricating ordered 2D superlattices of nanoparticles. Selfassembly of ligand protected nanoparticles is a simple technique, wherein the interparticle spacing is typically tuned by changing ligand molecules; self-assembly of diblock copolymer templates offers the possibility of tuning nanoparticle array packing and spacing using different substrates.…”

Preparation, Structure, and Properties of Hybrid Polymer Composites Containing Silver Clusters and Nanoparticles

“…In media with low polarity, the formation of SN leads to disappearance of the monomolecular micelles with diameter~34 nm and to appearance of polymolecular micelles with diameter~120 nm, which indicates participation of the SN in intermolecular cross-linking during preparation of the nanohybrid systems. The polymer micelles also act as nanoreactors and, by changing their dimensions, we may control the morphology of the SN formed [99]. The deposition of a dispersion of hybrid block copolymer/SN particles onto the surface of a substrate leads to their self-assembly to give cellular coatings, whose properties depend on the polymer concentration, composition of the medium, and nature of the substrate.…”

“…The deposition of a dispersion of hybrid block copolymer/SN particles onto the surface of a substrate leads to their self-assembly to give cellular coatings, whose properties depend on the polymer concentration, composition of the medium, and nature of the substrate. The use of copolymers with different structures and functionality permits controlled variation of the morphology of the SN as well as the structure and properties of the hybrid composites [98][99][100]. For example, a high content of siloxane fragments in the structure of the poly(methyl methacrylate)-PDMS block copolymer (poly(methyl methacrylate) = poly(MMA)) imparts enhanced hydrophobicity and thermal stability to its derived nanocomposites but a high concentration (>7 mass %) of SN is required to impart bactericidal activity to these materials [101].…”