Homogeneous Crystal Nucleation in Poly (butylene succinate--butylene adipate): Challenging the Nuclei-Transfer Step in Tammann's Method.

The kinetics of homogeneous crystal nucleation and the stability of nuclei were analyzed for a random butylene succinate/butylene adipate copolymer (PBSA), employing Tammann's two-stage crystal nuclei development method, with a systematic variation of the condition of nuclei transfer from the nucleation to the growth stage. Nuclei formation is fastest at around 0 °C, which is about 50 K higher than the glass transition temperature and begins after only a few seconds. Due to the high nuclei number, spherulitic growth of lamellae is suppressed.

Optimizing the Ion Conductivity and Mechanical Stability of Polymer Electrolyte Membranes Designed for Use in Lithium Ion Batteries: Combining Imidazolium-Containing Poly(ionic liquids) and Poly(propylene carbonate).

State-of-the-art Li batteries suffer from serious safety hazards caused by the reactivity of lithium and the flammable nature of liquid electrolytes. This work develops highly efficient solid-state electrolytes consisting of imidazolium-containing polyionic liquids (PILs) and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). By employing PIL/LiTFSI electrolyte membranes blended with poly(propylene carbonate) (PPC), we addressed the problem of combining ionic conductivity and mechanical properties in one material.

Advancing Antiamyloidogenic Activity by Fine-Tuning Macromolecular Topology.

Amyloid β peptide can aggregate into thin β-sheet fibrils or plaques deposited on the extracellular matrix, which is the hallmark of Alzheimer's disease. Multifunctional macromolecular structures play an important role in inhibiting the aggregate formation of amyloidogenic materials and thus are promising candidates with antiamyloidogenic characteristics for the development of next-generation therapeutics. In this study, we evaluate how small differences in the dendritic topology of these structures influence their antiamyloidogenic activity by the comparison of "perfectly dendritic" and "pseudodendritic" macromolecules, both decorated with mannose units.

N-Type Coating of Single-Walled Carbon Nanotubes by Polydopamine-Mediated Nickel Metallization.

Single-walled carbon nanotubes (SWCNTs) have unique thermal and electrical properties. Coating them with a thin metal layer can provide promising materials for many applications. This study presents a bio-inspired, environmentally friendly technique for CNT metallization using polydopamine (PDA) as an adhesion promoter, followed by electroless plating with nickel.

Unusual nonlinear switching in branched carbon nanotube nanocomposites.

In this experimental study, we investigate the nonlinear dynamic response of nanocomposite beams composed of polybutylene terephthalate (PBT) and branched carbon nanotubes (bCNTs). By varying the weight fraction of bCNTs, we obtain frequency response curves for cantilever specimens under harmonic base excitations, measuring the tip displacement via 3D scanning laser vibrometry. Our findings reveal a surprising nonlinear softening trend in the steady-state response of the cantilevers, which gets switched into hardening for higher bCNT weight fractions and increasing oscillation amplitudes.

Probing Crowdedness of Artificial Organelles by Clustering Polymersomes for Spatially Controlled and pH-Triggered Enzymatic Reactions.

Most sophisticated biological functions and features of cells are based on self-organization, and the coordination and connection between their cell organelles determines their key functions. Therefore, spatially ordered and controllable self-assembly of polymersomes to construct clusters to simulate complex intracellular biological functions has attracted widespread attention. Here, we present a simple one-step copper-free click strategy to cross-link nanoscale pH-responsive and photo-cross-linked polymersomes (less than 100 nm) to micron-level clusters (more than 90% in 0.

3D-printing of the polymer/insect-repellent system poly(l-lactic acid)/ethyl butylacetylaminopropionate (PLLA/IR3535).

The polymer/solvent system poly(l-lactic acid)/ethyl butylacetylaminopropionate (PLLA/IR3535) is regarded as an insect-repellent-delivery system, serving, e.g., for fighting mosquito-borne tropical diseases.

Influence of CNT Length on Dispersion, Localization, and Electrical Percolation in a Styrene-Butadiene-Based Star Block Copolymer.

This study followed the approach of dispersing and localizing carbon nanotubes (CNTs) in nanostructured domains of block copolymers (BCPs) by shortening the CNTs via ball milling. The aim was to selectively tune the electrical and mechanical properties of the resulting nanocomposites, e.g.

Laser-Assisted Direct Grafting of Poly(ethyleneimine) on Poly(methyl methacrylate).

Demand for direct chemical modification of functional material on a surface is increasing in various fields. A new approach for a functionalized surface is investigated by applying a conventional laser in order to generate chemical activation by photothermal energy. Poly(ethyleneimine) (PEI), with a high density of amino groups, is chemically grafted on poly(methyl methacrylate) (PMMA) by irradiation of a CO laser (10.

Thermal Stability and Nucleation Efficacy of Shear-Induced Pointlike and Shishlike Crystallization Precursors.

The different thermal stabilities of shear-induced pointlike and shishlike crystallization precursors of polyamide 11, generated in a parallel-plate rheometer and coexisting in the same sample, were quantified by hot-stage microscopy, by performing self-seed crystallization experiments. Crystals formed at low supercooling of the melt from these different types of precursors melt at about the same temperature. Annealing of the melt at different temperatures for a predefined time revealed dissolution/disordering of these precursors at 10-15 K higher temperature, near the equilibrium melting point.

Elastomeric microwell-based triboelectric nanogenerators by in situ simultaneous transfer-printing.

Self-powered tactile module-based electronic skins incorporating triboelectric nanogenerator (TENG) appears to be a worthwhile alternative for smart monitoring devices in terms of sustainable energy harvesting. On top of it, ultra-stretchability and detection sensitivity are imperative to mimic human skin. We report, for the first time, a metal-free single electrode TENG-based self-powered tactile module comprising of microwells (diameters 2 μm and 200 nm, respectively) on fluoroelastomer (FKM) and laser induced graphene (LIG) electrodes by in situ simultaneous transfer printing method.

Dopamine-Supported Metallization of Polyolefins─A Contribution to Transfer to an Eco-friendly and Efficient Technological Process.

Metallization is a common method to produce functional or decorative coatings on plastic surfaces. State-of-the-art technologies require energy-intensive process steps and the use of organic solvents or hazardous substances to achieve sufficient adhesion between the polymer and the metal layer. The present study introduces a facile bio-inspired "green" approach to improve this technology: the use of dopamine, a small-molecule mimic of the main structural component of adhesive mussel proteins, as an adhesion promoter.

Inducing nano-confined crystallization in PLLA and PET by elastic melt stretching.

Based on the widely studied poly(l-lactic acid) (PLLA) and polyethylene terephthalate (PET) that are brittle in their fully crystalline form, this Letter shows that they can be made to be super ductile, heat resistant and optically clear by creating nano-sized crystals while preserving the entanglement network. Atomic force microscopic images confirm the perceived nano-confined crystallization. Time-resolved X-ray scattering/diffraction measurements reveal the emergence of cold crystallization during either stress relaxation from large stepwise melt-stretching or annealing of pre-melt-stretched PLLA and PET above Tg.

Multiresponsive Transitions of PDMAEMA Brushes for Tunable Surface Patterning.

Poly(,-dimethylaminoethyl methacrylate) (PDMAEMA) is an attractive polymer for switchable surface coatings based on its multiresponsiveness toward environmental triggers (temperature, pH-value, ionic strength). In this in situ study, we present the complex and tunable thermoresponsiveness of PDMAEMA Guiselin brushes (9 nm, dry thickness), which were prepared via an efficient grafting-to approach. Combining in situ atomic force microscopy (AFM) visualizing the surface topography ( plane) and spectroscopic ellipsometry monitoring the swelling behavior of the polymer film (layer thickness, -direction) offers for the first time a three-dimensional insight into thermoresponsive transitions on the nanoscale.

Bioinspired Polydopamine Coating as an Adhesion Enhancer Between Paraffin Microcapsules and an Epoxy Matrix.

Microencapsulated phase change materials (PCMs) are attracting increasing attention as functional fillers in polymer matrices, to produce smart thermoregulating composites for applications in thermal energy storage (TES) and thermal management. In a polymer composite, the filler-matrix interfacial adhesion plays a fundamental role in the thermomechanical properties. Hence, this work aims to modify the surface of commercial PCM microcapsules through the formation of a layer of polydopamine (PDA), a bioinspired polymer that is emerging as a powerful tool to functionalize chemically inert surfaces due to its versatility and great adhesive potential in many different materials.

Enthalpy Relaxation, Crystal Nucleation and Crystal Growth of Biobased Poly(butylene Isophthalate).

The crystallization behavior of fully biobased poly(butylene isophthalate) (PBI) has been investigated using calorimetric and microscopic techniques. PBI is an extremely slow crystallizing polymer that leads, after melt-crystallization, to the formation of lamellar crystals and rather large spherulites, due to the low nuclei density. Based upon quantitative analysis of the crystal-nucleation behavior at low temperatures near the glass transition, using Tammann's two-stage nuclei development method, a nucleation pathway for an acceleration of the crystallization process and for tailoring the semicrystalline morphology is provided.

Bivalent Peptide- and Chelator-Containing Bioconjugates as Toolbox Components for Personalized Nanomedicine.

While personalized therapy bears an enormous potential in cancer therapy, the development of flexible, tailorable delivery systems remains challenging. Here, we present a "tool-kit" of various avidin-based bioconjugates (BCs) for the preparation of personalized delivery systems. Corresponding BCs were synthesized using the self-assembly of avidin with various biotinylated ligands, such as one cationic glycodendrimer for dendriplex adsorption and two functional ligands for imaging (glycodendrimers with DOTA or NOTA units) or targeting (biotinylated PEG decorated with ligands).

"Sliding Crystals" on Low-Dimensional Carbonaceous Nanofillers as Distributed Nanopistons for Highly Damping Materials.

Improving energy dissipation in lightweight polymer nanocomposites to achieve environmentally friendly and mechanically stable structures has reached a limit because of the low-density electrostatic interactions that can be harnessed through the stick-slip mechanism between carbonaceous nanofillers and polymeric chains wrapped around them. In this paper, the atomic friction between the two nanocomposite components is greatly amplified by locally increasing the density of the energetically higher noncovalent bonds. This gives rise to a new material design concept in which crystallite structures, nucleated around the carbonaceous nanofillers, become the source of enhanced energy dissipation.

Mono- and Polyassociation Processes of Pentavalent Biotinylated PEI Glycopolymers for the Fabrication of Biohybrid Structures with Targeting Properties.

This study describes new mechanistic insights in the sequential polyassociation of streptavidin with biotinylated poly(ethyleneimine) glycopolymers and biotinylated PEGylated folic acid components for the preparation of biohybrid structures (BHS) for controlled targeting experiments. Characterization of the BHS revealed that during the formation and postfunctionalization of BHS, reversible dissociation and reassociation processes occur. The BHS are stable over weeks after finalizing the equilibrium-driven polyassociation process.

Water-Responsive and Mechanically Adaptive Natural Rubber Composites by in Situ Modification of Mineral Filler Structures.

A new biomimetic stimuli-responsive adaptive elastomeric material, whose mechanical properties are altered by a water treatment is reported in this paper. This material is a calcium sulphate (CaSO) filled composite with an epoxidized natural rubber (ENR) matrix. By exploiting various phase transformation processes that arise when CaSO is hydrated, several different crystal structures of CaSO· xHO can be developed in the cross-linked ENR matrix.

Inductive Heating Using a High-Magnetic-Field Pulse to Initiate Chemical Reactions to Generate Composite Materials.

Induction heating is efficient, precise, cost-effective, and clean. The heating process is coupled to an electrically conducting material, usually a metal. As most polymers are dielectric and non-conducting, induction heating is not applicable.

Targeted delivery of TLR3 agonist to tumor cells with single chain antibody fragment-conjugated nanoparticles induces type I-interferon response and apoptosis.

Application of Toll-like receptor (TLR) agonists is a promising approach to treat cancer. In particular, nucleic acid-based TLR agonists such as short ssRNA and dsRNA molecules, which activate endosomal TLRs, can be delivered to tumors by use of nanoparticle delivery systems. However, such delivery systems bear unspecific side effects and poor pharmacokinetics.

Fluorocarbon-Free Dual-Action Textile Finishes Based on Covalently Attached Thermoresponsive Block Copolymer Brush Coatings.

We present fluorocarbon-free block copolymer brushes as potential systems for dual-action, i.e., soil-repellent and soil-releasing textile finishes.

Interactions of bioactive molecules with thin dendritic glycopolymer layers.

The authors report on highly swellable, stable layers of spherical dendritic glycopolymers, composed of hyperbranched poly(ethylene imine) (PEI) as core and two different maltose shells (A = dense shell and B = open shell). These glycopolymers are cross-linked and attached with poly(ethylene--maleic anhydride) (PEMA) or citric acid on SiO substrates. The swelling and adsorption of biomolecules were analyzed by spectroscopic ellipsometry and quartz crystal microbalance with dissipation.

A Poly(Propyleneimine) Dendrimer-Based Polyplex-System for Single-Chain Antibody-Mediated Targeted Delivery and Cellular Uptake of SiRNA.

Therapeutics based on small interfering RNAs (siRNAs) offer a great potential to treat so far incurable diseases or metastatic cancer. However, the broad application of siRNAs using various nonviral carrier systems is hampered by unspecific toxic side effects, poor pharmacokinetics due to unwanted delivery of siRNA-loaded nanoparticles into nontarget organs, or rapid renal excretion. In order to overcome these obstacles, several targeting strategies using chemically linked antibodies and ligands have emerged.