SEBS aggregate patterning at a surface studied by atomic force microscopy.

Xia Han; Jun Hu; Honglai Liu; Ying Hu

doi:10.1021/la051293i

Home/Archive/PubMed

PubMed · 16548611

SEBS aggregate patterning at a surface studied by atomic force microscopy.

Xia Han·Jun Hu·Honglai Liu·Ying Hu

View original source ↗Export metadata ↓

Abstract

The morphologies of films spin coated from dilute block copolymer solution onto a mica substrate were studied by atomic force microscopy (AFM). Variables of interest were the polymer concentration, solvent, heating temperature, aging, and ultrasonic effect. It is shown that the solution concentration is the predominant factor in determining the shape of the aggregates displayed from spheres and rods to irregular patches with increasing concentration. The solubility parameter of the solvent plays an important role in modifying the distribution and the size of clusters at the surface. The structures of the aggregates at the surface are metastable, which could evolve with temperature from rodlike aggregates into regular stripes when annealed at a temperature higher than the order-disorder transition temperature of SEBS, whereas those in solution could evolve with aging and ultrasonic treatment into a more stable network structure.

Explore related subjects

Aluminum Silicates Microscopy, Atomic Force Polyethylenes Polymers Polystyrenes Spin Labels Surface Properties Journal Article Research Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Xia Han, Jun Hu, Honglai Liu, Ying Hu. 2006-03-28. SEBS aggregate patterning at a surface studied by atomic force microscopy.. https://doi.org/10.1021/la051293i

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Solventless clay-promoted Friedel-Crafts reaction of indoles with alpha-amido sulfones: unexpected synthesis of 3-(1-arylsulfonylalkyl) indoles.

Friedel-Crafts reaction of indoles with alpha-amido sulfones in the presence of montmorillonite K-10 leads unexpectedly to 3-(1-arylsulfonylalkyl) indoles in good yield. The obtained products can be further desulfonylated under reductive or alkylative conditions giving linear and branched 3-substituted indoles.

Aluminum Silicates↗

PubMed2006

A molecular model for epsilon-caprolactam-based intercalated polymer clay nanocomposite: Integrating modeling and experiments.

In studying the morphology, molecular interactions, and physical properties of organically modified montmorillonite (OMMT) and polymer clay nanocomposites (PCNs) through molecular dynamics (MD), the construction of the molecular model of OMMT and PCN is important. Better understanding of interaction between various constituents of PCN will improve the design of polymer clay nanocomposite systems. MD is an excellent tool to study interactions, which require accurate modeling of PCN under consideration. Previously, the PCN models were constructed by different researchers on the basis of specific criteria such as minimum energy configuration, density of the polymer clay nanocomposite, and so forth. However, in this article we describe the development of models combining experimental and conventional molecular modeling to develop models, which are more representative of true intercalated PCN systems. The models were used for studying the morphological interactions and physical properties. These studies gave useful information regarding orientation of organic modifiers, area of coverage of organic modifiers over the interlayer clay surface, interaction of organic modifiers with clay in OMMT, interaction among different constituents of PCN, conformational and density change, and actual proportion of mixing of polymer with clay in PCN. We have X-ray diffraction and photoacoustic Fourier transform infrared spectroscopy to verify the model.

Aluminum Silicates↗

PubMed2006

Adhesion of spherical polyelectrolyte brushes on mica: an in situ AFM investigation.

We demonstrate that the adsorption of cationic spherical polyelectrolyte brushes (SPB) on negatively charged mica substrates can be controlled in situ by the ionic strength of the suspension. The SPB used in our experiments consist of colloidal core particles made of polystyrene. Long cationic polyelectrolyte chains are grafted onto these cores that have diameters in the range of 100 nm. These particles are suspended in aqueous solution with a fixed ionic strength. Atomic force microscopy (AFM) in suspension as well as in air was used for surface characterization. In pure water the polymer particles exhibit a strong adhesion to the mica surface. AFM investigations of the dry samples show that the particles occupy the identical positions as they did in liquid. They were not removed by the capillary forces within the receding water front during the drying process. The strong interaction between the particles and the mica surface is corroborated by testing the adhesion of individual particles on the dried surface by means of the AFM tip: after a stepwise increase of the force applied to the surface by the AFM tip, the polymer particles still were not removed from the surface, but they were cut through and remained on the substrate. Moreover, in situ AFM measurements showed that particles which adsorb under liquid in a stable manner are easily desorbed from the surface after electrolyte is added to the suspension. This finding is explained by a decreasing attractive particle-substrate interaction, and the removal of the particles from the surface is due to the significant reduction of the activation barrier of the particle desorption. All findings can be explained in terms of the counterion release force.

Aluminum Silicates↗