Journal of Polymer Science Part B: Polymer Physics

The image shows a fluorescence microscopy image of mouse mammary adenocarcinoma cells grown on polyimide with a patterned surface, as presented by Denise Langheinrich, Edith Yslas, Martín Broglia, Viviana Rivarola, Diego Acevedo, and Andrés Lasagni on page 415. The cells are highly aligned to the direction of the line-like pattern (spatial period: 1 μm), which was fabricated by using direct laser interference patterning technology. This flexible and rapid method offers the possibility of providing polymer and other surfaces with a variety of perfectly controlled periodic patterns by direct laser ablation.

The cover shows a high-resolution scanning electron micrograph of a silver metalized nanotube polymer composite (Ag-MNPC) at a high accelerating voltage. The single-wall carbon nanotubes (SWCNTs) dispersed in the Ag-MNPC appear as flexible curvy fibrils with the infused/reduced nanometer-scale-sized silver particles as bright round spots. The Ag-MNPC is prepared by supercritical fluid impregnation of an organosilver compound into a premade well-dispersed SWCNT-polymer composite film, as presented by Cheol Park, Jae-Woo Kim, Godfrey Sauti, Jin Ho Kang, Conrad S. Lovell, Luke J. Gibbons, Sharon E. Lowther, Peter T. Lillehei, Joycelyn S. Harrison, Negin Nazem, and Larry T. Taylor on page 394. The environmentally friendly metallization process significantly improves the toughness of the composite films as well as the electrical conductivity.

Polymers at low densities, or in a vacuum, have a number of interesting and important applications, but their underlying behavior has not been well understood. A range of unusual features emerge from their study and these also shed light on frictional effectsin polymer solutions. Their nonlinear dynamics give rise to surprising behavior such as damping that becomes zero at large length scales. A number of suggestions for experiments in this area are given.

Shape memory polymers (SMPs) with soft and elastomeric mechanical properties even in the “fixed” shape are drawing considerable attention for applications such as tissue engineering and dry adhesion. This work reports the preparation of a novel soft SMP nanocomposite consisting of a bacterial poly(3-hydroxyoctanoate-co-3-hydroxyundecenoate) (PHOU)-based covalent network grafted with inorganic––organic hybrid polyhedral oligomeric silsesquioxane (POSS). Because of its softness and reconfigurable nanostructure, the PHOU-–POSS SMP nanocomposite exhibits excellent bulk and microscale surface shape memory performances.

Metallized nanotube polymer composites (MNPCs), consisting of a lightweight polymer matrix, carbon nanotubes, and functional nanoparticles, can be tailored for effective shielding from various electromagnetic effects and harmful radiation.This study reports a novel method to develop well dispersed, highly functional MNPCs using environmentally benign supercritical fluid infusion, which possess high electrical conductivity and mechanical toughness.

Chain dynamics probed by dielectric spectroscopy provide understanding of the molecular interactions induced by hydration, crosslinking, and microstructural changes occurring on swelling of biopolymers such as chitosan. Chemical crosslinking and water bridges have similar influence on the secondary relaxation effect as well as producing similar hysteresis behavior that is paralleled by their ionic conductivity. Correlation between relaxation behavior and conductivity yields a power law behavior independent of the significant hysteresis with high fits over all crosslinking and water contents.

The physical and topological properties of polymeric biomaterials can control cell behavior. Contact guidance of cells on line-like micrometer and sub-micrometer patterns rapidly fabricated using the direct laser interference patterning (DLIP) method is studied here. Although the structure depths are less than 1 μm, cells strongly respond to them. For the smallest spatial period of Λ = 500 nm, the highest orientation (∼80%) is obtained.

Double-network (DN) hydrogels are particularly interesting for their similarities they share with biological systems and their impressive mechanical strength. A pH responsive DN system composed of two biocompatible polymers is shown to exhibit pH driven cluster formation caused by association between poly(ethylene glycol) side chains and a polyacrylic acid network. The clusters contribute to the enhanced strength and extensive de-swelling at low pH. The properties of these DN hydrogels are ideal for applications as artificial muscles or controlled release devices.

Polymer blends offer the opportunity to tailor materials properties, but they often need to have a compatibilizer added to ensure miscibility. The use of clay compatibilizers is increasing, since they offer high surface area, low monetary and environmental cost, and high stiffness. Here, blends of polystyrene and polypropylene with clay are studied to establish the relationship between amount of additive and mechanical and thermal properties, the mechanism of compatibilization, and location of the clay in the blend.

The aggregation of polymer chains plays an important role in the performance of organic field effect transistors and organic solar cells. Properties such as conjugation length, intermolecular coupling within the aggregates as well as the packing behavior of the polymer chains and disorder affect the applicable optic and electronic properties of poly(3-hexylthiophene). This study shows how the excitonic coupling and the resulting thin film mobility can be controlled by solvent quality.