Fibrin-Dextran Hydrogels with Tunable Porosity and Mechanical Properties.

Hydrogels as scaffolds in tissue engineering have gained increasing attention in recent years. Natural hydrogels, e.g.

Anisotropic Microgels by Supramolecular Assembly and Precipitation Polymerization of Pyrazole-Modified Monomers.

Soft colloidal macromolecular structures with programmable chemical functionalities, size, and shape are important building blocks for the fabrication of catalyst systems and adaptive biomaterials for tissue engineering. However, the development of the easy upscalable and template-free synthesis methods to obtain such colloids lack in understanding of molecular interactions that occur in the formation mechanisms of polymer colloids. Herein, a computer simulation-driven experimental synthesis approach based on the supramolecular self-assembly followed by polymerization of tailored pyrazole-modified monomers is developed.

Diffusion of Gold Nanorods Functionalized with Thermoresponsive Polymer Brushes.

Understanding the diffusion of gold nanorods (AuNRs) and their composites in dispersion is important at fundamental level and in fields as diverse as material science, nanobiotechnology to drug delivery. The translational and rotational diffusion of AuNRs decorated with thermoresponsive poly( N-isopropylacrylamide) brushes having hydrophilic and hydrophobic end groups was investigated in the dilute regime by dynamic light scattering. The same series of functionalized AuNRs were studied in the isotropic concentrated dispersions by high-resolution NMR diffusometry.

Thermodynamic Parameters of Temperature-Induced Phase Transition for Brushes onto Nanoparticles: Hydrophilic versus Hydrophobic End-Groups Functionalization.

Quantification of the stimuli-responsive phase transition in polymers is topical and important for the understanding and development of novel stimuli-responsive materials. The temperature-induced phase transition of poly(N-isopropylacrylamide) (PNIPAm) with one thiol end group depends on the confinement-free polymer or polymer brush-on the molecular weight and on the nature of the second end. This paper describes the synthesis of heterotelechelic PNIPAm of different molecular weights with a thiol end group-that specifically binds to gold nanorods and a hydrophilic NIPAm end group by reversible addition-fragmentation chain-transfer polymerization.

Peptizing Mechanism at the Molecular Level of Laponite Nanoclay Gels.

In the presence of additives such as etidronic acid (1-hydroxyethane-1,1-diphosphonic acid, HEDP), a process of peptizing of Laponite clay gels takes place. The peptizing process at the molecular level was directly revealed by P and H high-resolution magic-angle sample spinning (HRMAS) NMR spectroscopy. Two NMR spectral components were detected and assigned to free etidronic acid and bound to the Laponite disk edges.

Aggregation behaviour of biohybrid microgels from elastin-like recombinamers.

Investigation of the aggregation behavior of biohybrid microgels, which can potentially be used as drug carriers, is an important topic, because aggregation not only causes loss of activity, but also toxicity and immunogenicity. To study this effect we synthesized microgels from elastin-like recombinamers (ELRs) using the miniemulsion technique. The existence of aggregation for such biohybrid microgels at different concentrations and temperatures was studied by different methods which include dynamic light scattering (DLS), (1)H high-resolution magic angle sample spinning (HRMAS) NMR spectroscopy, relaxometry and diffusometry.

Coacervation of Elastin-Like Recombinamer Microgels.

The investigation of the coacervation (self-aggregation) behavior of biomicrogels which can potentially be used as drug carriers is an important topic, because self-aggregation can not only cause loss of activity, but also toxicity and immunogenicity. To study this effect microgels from elastin-like recombinamer are synthesized using miniemulsion technique. The existence of coacervation for such microgels, at different concentrations and temperatures, is studied and proved by cryo-field emission scanning clectron microscopy (cryo-FESEM), cryo-transmission electron microscopy (cryo-TEM), and by a novel (1) H high-resolution magic angle sample spinning (HRMAS), nuclear magnetic resonance (NMR) spectroscopy, and relaxometry methods.

Nacre-mimetics with synthetic nanoclays up to ultrahigh aspect ratios.

Nacre-mimetics hold great promise as mechanical high-performance and functional materials. Here we demonstrate large progress of mechanical and functional properties of self-assembled polymer/nanoclay nacre-mimetics by using synthetic nanoclays with aspect ratios covering three orders in magnitude (25-3,500). We establish comprehensive relationships among structure formation, nanostructuration, deformation mechanisms and mechanical properties as a function of nanoclay aspect ratio, and by tuning the viscoelastic properties of the soft phase via hydration.

Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone.

Tough and catalytically active hybrid biofibers wet-spun from nanochitin hydrogels.

Sustainable alternatives for high-performance and functional materials based on renewable resources are intensely needed as future alternatives for present-day, fossil-based materials. Nanochitin represents an emerging class of highly crystalline bionanoparticles with high intrinsic mechanical properties and the ability for conjugation into functional materials owing to reactive amine and hydroxyl groups. Herein we demonstrate that hydrogels containing surface-deacetylated chitin nanofibrils of micrometer length and average diameters of 9 nm, as imaged by cryogenic transmission electron microscopy, can be wet-spun into macrofibers via extrusion in a coagulation bath, a simple low energy and large-scale processing route.