Microgel containers for self-healing polymeric materials: Morphology prediction and mechanism of formation

18 types of gel microparticles, composed of 3 polymer types and 6 different solvents, were prepared by interfacial polymerization and compared in a systematic way with respect to their structure and function. Three types of morphologies, specific for each polymer-solvent pair, were observed: core-shell, multicompartment and compact. The morphology was found to be a direct consequence of the specific polymer-solvent interactions and can be, in most cases, predicted on the basis of simple swelling experiments with a chosen polymer in the solvent. Further, the Hansen Solubility Parameters approach was applied to the investigated systems enabling a reliable morphology prediction of microgel particles made of any polymer/solvent combination with known solubility parameters (spheres). The mechanisms responsible for the formation of particles with different morphologies are also discussed

Transformation of worst weed into N-, S-, and P-tridoped carbon nanorings as metal-free electrocatalysts for the oxygen reduction reaction

Substituting sustainable/cost-effective catalysts for scarce and costly metal ones is currently among the major targets of sustainable chemistry. Herein we report the synthesis of N-, S-, and P-tridoped, worst-weed-derived carbon nanorings (WWCNRs) that can serve as metal-free and selective electrocatalyst for the oxygen reduction reaction (ORR). The WWCNRs are synthesized via activation-free polymerization of worst weed, Eclipta prostrate, and then removal of the metallic residues by HCl. The WWCNRs exhibit good catalytic activity towards the 4 electron-transfer ORR with low onset potential and high kinetic limiting current density, along with high selectivity (introducing CO, the sample loses onl

Polymer-decorated anisotropic silica nanotubes with combined shape and surface properties for guest delivery

We report on amphiphilic diblock copolymer-decorated anisotropic silica nanotubes with well-defined dual functions of shape and surface properties in one nanocontainer. Amphiphilic poly(lactic acid)block-poly(ethylene glycol) (PLA-b-PEG) diblock copolymers are covalently grafted to the surface of mesoporous silica nanotubes via silane chemistry and esterification. The released percentage of probe molecules from the resultant silica-g-(PLA-b-PEG) hybrid nanocontainer is around 40% over a release time of 48 h, in contrast to 90% from bare silica nanotubes prior to surface modification. The diblock copolymer-decorated anisotropic nanocontainers with large aspect ratio lead to enhanced viability of NIH 3T3 fibroblast cells. A theoretical model based on the free energy cost for cell membranes to encapsulate nanocontainers is utilized to understand the cytotoxicity. This work demonstrates that the release dynamics of the active molecules and the interaction of hybrid nanocontainers with cell membranes can be regulated by the synergistic effect of nanocontainer shape and surface properties. (C) 2016 Elsevier Ltd. All rights reserved.</p

Polyelectrolyte Multilayers: Towards Single Cell Studies

Single cell analysis (SCA) is nowadays recognized as one of the key tools for diagnostics and fundamental cell biology studies. The Layer-by-layer (LbL) polyelectrolyte assembly is a rather new but powerful technique to produce multilayers. It allows to model the extracellular matrix in terms of its chemical and physical properties. Utilization of the multilayers for SCA may open new avenues in SCA because of the triple role of the multilayer film: (i) high capacity for various biomolecules; (ii) natural mimics of signal molecule diffusion to a cell and (iii) cell patterning opportunities. Besides, light-triggered release from multilayer films offers a way to deliver biomolecules with high spatio-temporal resolution. Here we review recent works showing strong potential to use multilayers for SCA and address accordingly the following issues: biomolecule loading, cell patterning, and light-triggered release

Hollow polypyrrole containers with regulated uptake/release properties

Polypyrrole microcontainers were successfully prepared by electrochemical polymerization of pyrrole on the surface of stainless steel electrodes. The size of the nanocontainers and the thickness of the polypyrrole shell (up to complete tilling of the container with grown polypyrrole) can be varied by changing both the scan speed of the electrode potential and potential range. Polypyrrole surfaces with high redox current due to their increased surface area are obtained; for optimized conditions, also microcontainers are obtained. The polypyrrole microcontainers with a size of less than 20 mu m can be easily detached from the electrode surface and polypyrrole films during several minutes of sonication in an ultrasonic bath. The polypyrrole shell of the microcontainers exhibits very strong barrier properties in acidic media at 2 7, providing effective encapsulation of low molecular weight species at low pH values