Force Required to Disassemble Block Copolymer Micelles in Water

The force required to disassemble block copolymer micelles in water has been directly investigated via atomic force microscopy-based single-molecule force spectroscopy. The force needed to disassemble block copolymer micelles of poly(acrylic acid)-polyfluorene-poly(acrylic acid) in water is found to be 23 pN. The force increases as the stretching velocity increases, indicating that micelle disassembly is a dynamic process. In addition, the disassembly force is sensitive to the properties of the solvents. This study represents the first attempt to employ single-molecule force spectroscopy to directly measure the force needed to disassemble block copolymer micelles in water

Growth Mechanisms of 2D Organic Assemblies Generated from Dialkylated Melaminium Derivatives: The Length Difference of the Two Alkyl Chains That Matters

This research is aimed to understand the growth mechanisms for self-assembly of dialkylated melamine derivatives. The dialkylated melamine derivatives with different alkyl chains (Mela-<i>m</i>-<i>n</i>) are able to self-assemble with hydrochloric acid in dichloromethane to form 2D organic assemblies, exhibiting similar lamellar structures as Mela-<i>n</i>·HCl with identical alkyl chains. The most interesting finding is that the growth mechanism of Mela-<i>n</i>·HCl with identical alkyl chains is revealed to be layer growth, while Mela-<i>m</i>-<i>n</i>·HCl with asymmetric alkyl chains adopts a spiral growth mechanism. The asymmetric alkyl chains in Mela-<i>m</i>-<i>n</i> may lead to the formation of dislocation, which is responsible for the spiral growth mechanism

Asymmetric and Symmetric Bolaform Supra-Amphiphiles: Formation of Imine Bond Influenced by Aggregation

A series of bolaform supra-amphilphiles with different symmetries were fabricated through dynamic benzoic imine bond formation. The pH dependence of imine formations of these supra-amphiphiles were characterazied. We found that the extent of the imine formation of these supra-amphiphies were different. The supra-amphiphiles with a poorer symmetry always exhibited a lower imine formation at a given pH. Therefore, the varied extent of imine bond formation indicate the different aggregations of these supra-amphilphiles, which are controlled by the molecular symmetry of the supra-amphiphiles

Poly(acrylic acid)-Bearing Photoreactive Azido Groups for Stabilizing Multilayer Films

In this article, we have demonstrated a universal method for improving the stability of polyelectrolyte multilayer films by designing a photoreactive polyanion as the building block for layer-by-layer (LbL) self-assembly. By grafting an azido group into poly(acrylic acid), we synthesized a photoreactive polyanion, which can induce the photo-cross-linking between the azido group and polymeric backbone under UV irradiation. Our results show that after photo-cross-linking, the stability of the polyelectrolyte multilayer is greatly improved. Considering that the polyanion-bearing azido group is highly reactive, we have shown that it can be used to stabilize different LbL films. Moreover, by taking advantage of the different stability before and after UV irradiation, a patterned surface can be fabricated, which could be used as a template for selective adsorption

Bolaform Supramolecular Amphiphiles as a Novel Concept for the Buildup of Surface-Imprinted Films

Stable multilayer films were fabricated on the basis of the alternating layer-by-layer assembly of a two-component bolaform supramolecular amphiphile and diazoresins, followed by photochemical cross-linking of the structure. UV–visible spectroscopy and atomic force microscopy revealed a uniform deposition process. Moreover, one component of the supramolecular amphiphile can be removed from the multilayer films after cross-linking between the second component and the diazoresin. The release and uptake of the imprinted supramolecular amphiphile component are shown to be reversible. Furthermore, uptake experiments of different molecules show the selectivity of the imprinted sites for the template molecule. Thus, surface-imprinted films can be formed by employing dissociable two-component supramolecular amphiphiles. This research reveals that supramolecular amphiphiles can be used as a novel concept for the construction of multilayer films, and it also provides a new method of generating surface-imprinted multilayers

Metal–Organic Dimerization of Dissymmetrical Ligands toward Customized Through-Space Chromophore Interactions

The pursue of good photophysical properties for organic optoelectronic materials requires a well understanding of through-space chromophore interactions, which further requires a well control over the spatial arrangement of chromophores. However, it remains a challenge to precisely customize the positioning of chromophores in their aggregating form such as in a simplest cofacially stacked dimer. Herein, this work provides a customizable molecular design based on dissymmetrical ligands that can enable a precise control over chromophore interactions through the formation of metal–organic dimers. Anti-paralleled stacking of two dissymmetrical ligands in the metal–organic dimers results in a lateral shifting of chromophore stacking, whose spacing is determined and adjusted by the degree of ligand dissymmetry. Three metal–organic dimers with a variation in chromophore spacing exhibited unique photophysical properties in both solution and solid states and displayed high-efficient luminescence against quenching in their aggregating states. This strategy thereby offers a universally applicable way to construct chromophore dimers with fixed cofacial spacing and determinate through-space interactions

Metal–Organic Dimerization of Dissymmetrical Ligands toward Customized Through-Space Chromophore Interactions

The pursue of good photophysical properties for organic optoelectronic materials requires a well understanding of through-space chromophore interactions, which further requires a well control over the spatial arrangement of chromophores. However, it remains a challenge to precisely customize the positioning of chromophores in their aggregating form such as in a simplest cofacially stacked dimer. Herein, this work provides a customizable molecular design based on dissymmetrical ligands that can enable a precise control over chromophore interactions through the formation of metal–organic dimers. Anti-paralleled stacking of two dissymmetrical ligands in the metal–organic dimers results in a lateral shifting of chromophore stacking, whose spacing is determined and adjusted by the degree of ligand dissymmetry. Three metal–organic dimers with a variation in chromophore spacing exhibited unique photophysical properties in both solution and solid states and displayed high-efficient luminescence against quenching in their aggregating states. This strategy thereby offers a universally applicable way to construct chromophore dimers with fixed cofacial spacing and determinate through-space interactions

Metal–Organic Dimerization of Dissymmetrical Ligands toward Customized Through-Space Chromophore Interactions

The pursue of good photophysical properties for organic optoelectronic materials requires a well understanding of through-space chromophore interactions, which further requires a well control over the spatial arrangement of chromophores. However, it remains a challenge to precisely customize the positioning of chromophores in their aggregating form such as in a simplest cofacially stacked dimer. Herein, this work provides a customizable molecular design based on dissymmetrical ligands that can enable a precise control over chromophore interactions through the formation of metal–organic dimers. Anti-paralleled stacking of two dissymmetrical ligands in the metal–organic dimers results in a lateral shifting of chromophore stacking, whose spacing is determined and adjusted by the degree of ligand dissymmetry. Three metal–organic dimers with a variation in chromophore spacing exhibited unique photophysical properties in both solution and solid states and displayed high-efficient luminescence against quenching in their aggregating states. This strategy thereby offers a universally applicable way to construct chromophore dimers with fixed cofacial spacing and determinate through-space interactions

On-Resin Recognition of Aromatic Oligopeptides and Proteins through Host-Enhanced Heterodimerization

Peptide dimerization is ubiquitous in natural protein conjugates and artificial self-assemblies. A major challenge in artificial systems remains achieving quantitative peptide heterodimerization, critical for next-generation biomolecular purification and formulation of therapeutics. Here, we employ a synthetic host to simultaneously encapsulate an aromatic and a noncanonical l-perfluoro­phenyl­alanine-containing peptide through embedded polar−π interactions, constructing an unprecedented series of heteropeptide dimers. To demonstrate the utility, this heteropeptide dimerization strategy was applied toward on-resin recognition of N-terminal aromatic residues in peptides as well as insulin, both exhibiting high recycling efficiency (>95%). This research unveils a generic approach to exploit quantitative heteropeptide dimers for the design of supramolecular (bio)­systems