Search results for "polymerization"
showing 10 items of 1689 documents
Cylindrical Polypeptide Brushes
2005
Cylindrical brushes with poly(L-lysine) and poly(L-glutamate) side chains were prepared by grafting through and grafting from techniques. Grafting from is shown to be more successful for the synthesis of cylindrical brushes with high molar mass main and side chains.
Quantitative analysis of localized surface plasmons based on molecular probing
2010
International audience; We report on the quantitative characterization of the plasmonic optical near-field of a single silver nanoparticle. Our approach relies on nanoscale molecular molding of the confined electromagnetic field by photoactivated molecules. We were able to directly image the dipolar profile of the near-field distribution with a resolution better than 10 nm and to quantify the near-field depth and its enhancement factor. A single nanoparticle spectral signature was also assessed. This quantitative characterization constitutes a prerequisite for developing nanophotonic applications.
Nanoporous Thin Films Based on Polylactide-Grafted Norbornene Copolymers
2008
Thermally stable vinyl polymerized polynorbornene (PNB) is one of the challenging materials in porous low dielectric films for packaging applications. Nanoporous PNB thin films were obtained with poly(d,l-lactide) (PLA)-grafted norbornene copolymers. Thermally labile PLA chains act as pore generators in PNB films. Thermally stable PNB main chains were synthesized by Pd-catalyzed vinyl polymerization and PLA side chains were grafted onto the PNB main chains by ring opening polymerization. The brittle and poor processible properties of PNB could easily be controlled by the copolymerization with norbornene derivatives. In thin films, the PLA chains were found to thermally decompose at about 25…
Mass‐Spectrometric Imaging of Electrode Surfaces—a View on Electrochemical Side Reactions
2020
Abstract Electrochemical side reactions, often referred to as “electrode fouling”, are known to be a major challenge in electro‐organic synthesis and the functionality of modern batteries. Often, polymerization of one or more components is observed. When reaching their limit of solubility, those polymers tend to adsorb on the surface of the electrode, resulting in a passivation of the respective electrode area, which may impact electrochemical performance. Here, matrix‐assisted laser‐desorption/ionization mass spectrometry (MALDI‐MS) is presented as valuable imaging technique to visualize polymer deposition on electrode surfaces. Oligomer size distribution and its dependency on the contact …
Polymeric nanospheres as strategy to increase the amount of triclosan retained in the skin: passive diffusion vs. iontophoresis
2012
The aim of this study was to evaluate the passive and iontophoretic permeation of triclosan in human skin using a triclosan solution and triclosan-loaded cationic nanospheres in order to determine which of the two strategies is more effective in allowing the deposition of triclosan within the skin. Triclosan-loaded nanospheres were prepared by the emulsification-solvent displacement technique using aminoalkyl methacrylate (Eudragit® RL 100) as polymer matrix. Nanospheres of 261.0 ± 15.1 nm with a positive surface charge (Ψz = 26.0 ± 3.2 mV) were obtained. Drug loading was 62.0 ± 1.7%. Results demonstrated that the amount of triclosan retained within the skin was significantly greater (8.5-f…
Design of Carbon Dots Photoluminescence through Organo-Functional Silane Grafting for Solid-State Emitting Devices
2017
AbstractAdvanced optical applications of fluorescent carbon dots (C-dots) require highly integrated host-guest solid-state materials with a careful design of C-dots – matrix interface to control the optical response. We have developed a new synthesis based on the grafting of an organo-functional silane (3-glycidyloxypropyltrimethoxysilane, GPTMS) on amino-functionalized C-dots, which enables the fabrication of highly fluorescent organosilica-based hybrid organic-inorganic films through sol-gel process. The GPTMS grafting onto C-dots has been achieved via an epoxy–amine reaction under controlled conditions. Besides providing an efficient strategy to embed C-dots into a hybrid solid-state mat…
ZnO-latex hybrids obtained by polymer-controlled crystallization: a spectroscopic investigation.
2007
Micro- and submicrosized ZnO-polymer hybrid materials were synthesized by precipitating zinc oxide from an aqueous medium in the presence of poly(styrene-acrylic acid) latex nanoparticles, prepared by miniemulsion polymerization. Up to 10 wt % of the latex becomes incorporated into the crystals. Although the long-range order of the inorganic material is essentially not altered by the polymer, studies by photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) show that the latex particles influence the optical and paramagnetic properties of the hybrids, which can be correlated with changes in the defect structure. Typical PL emission spectra showed a narrow UV peak and …
The effect of extracellular matrix proteins on the cellular response of HUVECS and HOBS after covalent immobilization onto titanium
2014
Biomimetic surface modifications are regarded as promising approach to stimulate cellular behavior at the interface of implant materials. Aim of the study was an evaluation of the cellular response of human umbilical cord cells (HUVECS) and human osteoblasts (HOBS) on titanium covalently coated with the extracellular matrix (ECM) proteins fibrinogen, collagen, laminin, and osteopontin. For the surface modification, titanium discs were first amino-functionalized by plasma polymerization of allylamine. The ECM protein conjugation was performed using the linker molecule α, ω-bis-N-hydroxysuccinimide polyethylene glycol (Di-NHS linker). For surface characterization, infrared spectroscopy and fl…
Phase behavior of low-functionality, telechelic star block copolymers.
2010
We apply state-of-the-art, Grand Canonical Monte Carlo simulations to determine the self-organization and phase behavior of solutions of block copolymer stars. The latter consist of f AB-block copolymers with N monomers each, which contain a solvophilic block A and solvophobic block B, and which are tethered on a common center on their A-side. We vary the degree of polymerization N and the relative composition of the block copolymer arms and investigate the interplay between macrophase and microphase separation in the system. Preliminary results of the effect of increasing the number of arms, f of the stars are also presented.