Rapid capture of biomolecules from blood via stimuli-responsive elastomeric particles for acoustofluidic separation

Detection of biomarkers often requires extensive sample preparation. We report a simple acoustofluidic method to isolate biomarkers on elastomeric particles by co-aggregation of elastin-like polypeptides, enabling their efficient capture and release.

Thermally and electrically conducting polycarbonate/elastomer blends combined with multiwalled carbon nanotubes

In this article, we have studied thermal and dielectric conductivity and morphology of polycarbonate (PC)/ethylene–propylene copolymer (EPC)/multiwalled carbon nanotubes (MWCNTs) nanocomposites. Transmission electron microscopy has been used to investigate the localization and migration of MWCNTs within the matrix. The MWCNTs were located in the PC phase and at the interface of PC and EPC. The results showed that the thermal conductivity of the PC decreased with the increasing content of EPC elastomeric particles. However, at the same time, one could observe an increase of the thermal conductivity in the polymer blends along with an addition of MWCNT. The electrical conductivity of the PC/EPC blends containing 10 wt% of EPC increased with the incorporation of MWCNTs, and the conducting paths were formed at additive content less than 0.5 wt% of MWCNT.

Effects of compatilizers on the cellular structures, interfacial morphologies and mechanical properties of PP foam composites

The short glass fiber (SGF)/polypropylene (PP) and ethylene-1-octene copolymer (POE)/SGF/PP foam composites were prepared by extrusion and subsequent post-foaming process in designed dies. The compatilizers, maleic anhydride grafted PP (PP-g-MAH) and maleic anhydride grafted POE (POE-g- MAH), were employed to improve the performance of the foam composites, respectively, and their influences on the cellular structures, interfacial morphologies and mechanical properties of PP foam composites were investigated. It was found that the compatilizers resulted in modified PP foam composites characterized by uniform cell size distribution, reduced cell size and increased cell density except POE/SGF/PP with POE-g-MAH. The obvious enhanced SGF-matrix interfacial bonding was observed from the SEM examination, and POE-g-MAH also facilitated the compatibility between elastomeric particles and matrix. Testing results indicated that, by the introduction of PP-g-MAH or POE-g-MAH, the mechanical properties of PP foam composites were significantly improved, and it seemed that the PP-g-MAH was more effective in strengthening the flexural and compressive strength while POE-g-MAH greatly increased the impact toughness.

Poly(Dimethylsiloxane) Elastomers from Aqueous Emulsions: I. Preparations, and Characterization of the Curing and Aging Processes

Poly(dimethylsiloxane) (PDMS) elastomers were prepared from aqueous emulsions, in combination with one of several carefully chosen alkoxy silanes as a crosslinking agent, and either stannous-2-ethylhexanoate or dioctylitin dilaurate as catalyst. Conditions were generally chosen so as to generate silica/silicate phases within the elastomeric particles or at their surfaces, for improvements in mechanical properties of films to be cast from the emulsions. A series of such films was obtained from emulsions consisting of various combinations of these ingredients, and was then characterized, primarily by measurements of soluble fractions, and by extents of equilibrium swelling (as inverse measures of degrees of crosslinking). Of primary interest were experimental results clarifying the mechanisms for the PDMS crosslinking and for the subsequent “aging” of these materials. For all the systems, increase in concentration of crosslinking agent was found to decrease the fraction of soluble polymer present and to decrease the extent of swelling. The extent to which this occurred, however, varied significantly with the nature of the alkoxy silane crosslinking agent, its concentration, and the nature of the catalyst. The observed differences were used to propose mechanisms with regard to the role of the silanes in the formation of silica-like phases, as well as for the endlinking of the PDMS chains. The formation of this inorganic phase was found to have a large effect on the extraction and swelling results, particularly through its barrier effects on the surfaces of the emulsion particles. Aging effects were found to depend not only on the nature of the reactants and their concentrations in the preparation of the emulsions, but also on whether the aging had been carried out in the dry state or in the wet state. Two major effects were decreases in soluble polymer fraction and extent of swelling with time. These changes were associated with increases in degree of crosslinking, but opposing changes can arise from bond cleavages or reorganizations. It appeared that dry-state aging effects are greatest for systems with a low concentration of the precipitated inorganic phase, with the effects of aging being suppressed by the presence of the inorganic, filler-like phases.