Dimensional architecture of ferrocenyl-based oligomer honeycomb-patterned films: from monolayer to multilayer

Fabrication of Pore-Selective Metal-Nanoparticle-Functionalized Honeycomb Films via the Breath Figure Accompanied by In Situ Reduction

Honeycomb films pore-filled with metal (Au, Ag, and Cu) nanoparticles were successfully prepared by combining the breath figure method and an in situ reduction reaction. First, a polyhedral oligomeric silsesquioxane (POSS)-based star-shaped polymer solution containing metal salt was cast under humid conditions for the formation of honeycomb films pore-filled with metal salt through the breath figure method. The morphology of the honeycomb films was mainly affected by the polymer molecular structure and the metal salt. Interestingly, the promoting effect of the metal salt in the breath figure process was also observed. Then, honeycomb films pore-filled with metal nanoparticles were obtained by in situ reduction of the honeycomb films pore-filled with metal salt using NaBH4. Notably, the metal nanoparticles can be selectively functionalized in the pores or on the surface of the honeycomb films by controlling the concentration of the NaBH4. Metal-nanoparticle-functionalized honeycomb films can prospectively be used in catalysis, flexible electrodes, surface-enhanced Raman spectroscopy (SERS), and wettability patterned surfaces.

Interfacial rheological behaviors of amphiphilic sodium cholesteryl glycylglycine

The present study was conducted to investigate the effects of the strong van der Waals interaction and sterol skeleton of surfactants on their interfacial rheological behaviors by comparing the interfacial properties of sodium cholesteryl glycylglycine (Chol-GG-Na) and sodium lauryl glycylglycine (C12-GG-Na) at the oil-aqueous interface. The interfacial dilational rheological experiment results indicate a significant increase in the interfacial activity and intermolecular interaction with the introduction of the cholesteryl group. Therefore, a compact interfacial layer with a remarkably high dilational modulus was obtained with the adsorption of Chol-GG-Na. The cholesteryl group also has a significant impact on the dynamic processes such as it slows down the motion of the molecules due to which the diffusion exchange between the bulk and the interface decreases. Besides, the rigid skeleton makes rearrangement and conformation adjustment difficult. These impacts become more pronounced when the adsorption layer approaches a close and ordered arrangement, which has been confirmed by the relaxation measurements. The reported results provide a theoretical foundation for the potential applications of cholesteryl-based surfactants in the food, pharmaceutical, cosmetic and petroleum industries.

Controlling breath figure patterns on PDMS by concentration variation of ethanol-methanol binary vapors

In this paper, the self-assembly of condensed droplets on smooth and constrained surfaces under saturated vapor atmosphere of ethanol and methanol binary system is reported. Hexagonally ordered array of pores are obtained on smooth surfaces with saturated vapors of binary liquids without the assistance of any additives. The results show that the addition of a small amount of ethanol to methanol plays a role very similar to that of surface active agents in inducing the formation of a regular droplet array. The effect of constraints on a self-assembled droplet pattern such as the movement of the contact line and the depinning of the contact line is also investigated. It is observed that the pore size, pore shape, pore depth and ring diameter are influenced by the atmosphere of binary vapors in addition to the commonly held attribution to the surface tension of the solvent. Contact angle studies of the patterned substrates show hydrophobicity with high adhesiveness and transitions between the Wenzel and Cassie impregnating state over the entire concentration region.

Breath-Figure Self-Assembly, a Versatile Method of Manufacturing Membranes and Porous Structures: Physical, Chemical and Technological Aspects

The review is devoted to the physical, chemical, and technological aspects of the breath-figure self-assembly process. The main stages of the process and impact of the polymer architecture and physical parameters of breath-figure self-assembly on the eventual pattern are covered. The review is focused on the hierarchy of spatial and temporal scales inherent to breath-figure self-assembly. Multi-scale patterns arising from the process are addressed. The characteristic spatial lateral scales of patterns vary from nanometers to dozens of micrometers. The temporal scale of the process spans from microseconds to seconds. The qualitative analysis performed in the paper demonstrates that the process is mainly governed by interfacial phenomena, whereas the impact of inertia and gravity are negligible. Characterization and applications of polymer films manufactured with breath-figure self-assembly are discussed.

Hierarchical honeycomb-structured films by directed self-assembly in “breath figure” templating of ionizable “clicked” PH3T-b-PMMA diblock copolymers: an ionic group/counter-ion effect on porous polymer film morphology

Impact of the ionization of “clicked” rod–coil diblock copolymers on their directed self-assembly in “breath figure” templating for hierarchically honeycomb-structured films.

Tailored honeycomb-like polymeric films based on amphiphilic poly(urea/malonamide) dendrons

A series of hydrogen bond-rich poly(urea/malonamide) dendrons were utilized as surfactants to facilitate the formation of honeycomb-like porous structures from the breath figure (BF) process.

Breath Figure Method for Construction of Honeycomb Films

Honeycomb films with various building units, showing potential applications in biological, medical, physicochemical, photoelectric, and many other areas, could be prepared by the breath figure method. The ordered hexagonal structures formed by the breath figure process are related to the building units, solvents, substrates, temperature, humidity, air flow, and other factors. Therefore, by adjusting these factors, the honeycomb structures could be tuned properly. In this review, we summarized the development of the breath figure method of fabricating honeycomb films and the factors of adjusting honeycomb structures. The organic-inorganic hybrid was taken as the example building unit to discuss the preparation, mechanism, properties, and applications of the honeycomb films.

Porphyrinated polyimide honeycomb films with high thermal stability for HCl gas sensing

Thermally stable films with ordered pores are fabricated from porphyrinated polyimides and they exhibit excellent property in HCl gas sensing.

Self-assembly of graphene oxide at interfaces

Due to its amphiphilic property, graphene oxide (GO) can achieve a variety of nanostructures with different morphologies (for example membranes, hydrogel, crumpled particles, hollow spheres, sack-cargo particles, Pickering emulsions, and so on) by self-assembly. The self-assembly is mostly derived from the self-concentration of GO sheets at various interfaces, including liquid-air, liquid-liquid and liquid-solid interfaces. This paper gives a comprehensive review of these assembly phenomena of GO at the three types of interfaces, the derived interfacial self-assembly techniques, and the as-obtained assembled materials and their properties. The interfacial self-assembly of GO, enabled by its fantastic features including the amphiphilicity, the negatively charged nature, abundant oxygen-containing groups and two-dimensional flexibility, is highlighted as an easy and well-controlled strategy for the design and preparation of functionalized carbon materials, and the use of self-assembly for uniform hybridization is addressed for preparing hybrid carbon materials with various functions. A number of new exciting and potential applications are also presented for the assembled GO-based materials. This contribution concludes with some personal perspectives on future challenges before interfacial self-assembly may become a major strategy for the application-targeted design and preparation of functionalized carbon materials.

Estimation of electron transfer properties of ferrocenyl-dicholesteryl-peptide in liquid and gel

Molecular dynamics simulations were carried out to investigate the conformations of ferrocenyl-dicholesteryl N-formamidoformamide (Fc-LS2) molecules in solvents of methanol and 1-propanol. Fc-LS2 comprises ferrocene and cholesteryl units linked by a biocompatible N-formamidoformamide peptide unit. Our results showed that Fc-LS2 formed a gel with 1-propanol but not with methanol. Charge-transfer properties of Fc-LS2/1-propanol gel and Fc-LS2/methanol liquid were also investigated by quantum mechanical (QM) calculations. The QM results indicate that the amino acid linkages contribute to improved charge-transport properties and the transfer integrals of Fc-LS2/1-propanol are larger than those of Fc-LS2/methanol.

Multiple interfaces in self-assembled breath figures

Progress in the breath figure method is reviewed by emphasizing the role of the multiple interfaces and the applications of honeycomb films in separation, biocatalysis, biosensing, templating, stimuli-responsive surfaces and adhesive surfaces.