Search results for "ionic"

SYNTHESIS AND CHARACTERIZATION OF POLYAMINOACIDIC POLYCATIONS FOR GENE DELIVERY

2005

The properties as non viral gene vector of a protein-like polymer, the alpha,beta-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) were exploited after its derivatization with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) as molecule bearing a cationic group, in order to obtain stable polycations able to condense DNA. PHEA was firstly functionalized with aminic pendant groups by reaction with ethylenediamine (EDA) obtaining the alpha,beta-poly(N-2-hydroxyethyl)(2-aminoethylcarbamate)-d,l-aspartamide (PHEA-EDA) copolymer. We demonstrated that polymer functionalization degree is easily modulable by varying reaction conditions, so allowing to produce two PHEA-EDA derivatives at different mo…

The effect of polycations on early cement paste

2010

International audience; This paper studies the possibility for improving the ductility of cement based materials by means of oligocationic additives. Actually, the setting of cement is due to ionic correlation forces between highly negatively charged C-S-H nanoparticles throughout a calcium rich solution. The main drawback of this strong attraction is its very short range that results in low elastic deformation of hydrated cementitious materials. A way to enlarge the attraction range between C-S-H particles would be to add cationic oligomers that would compete with calcium ions modifying the ionic correlation forces via a bridging mechanism of longer range, which could lead to a more ductil…

Ionic Liquid-Based Electrolytes for Supercapacitor and Supercapattery

2019

There is a strong desire to replace or complement aqueous and organic electrolytes by ionic liquids (ILs) in electrochemical energy storage (EES) devices to achieve high operating voltages and hence high energy capacity. ILs are regarded as the inherent and competitive electrolytes since they were introduced to the electrochemical research community because they can overcome many disadvantages of the conventional aqueous and organic electrolytes, such as narrow potential windows, volatility, and flammability. This paper reviews critically the recent literatures of IL-based electrolytes used in supercapacitor, supercapattery, and micro-supercapacitor. Supercapattery is a generic term for var…

Hybrid catalysts for CO 2 conversion into cyclic carbonates

2019

The conversion of carbon dioxide into valuable chemicals such as cyclic carbonates is an appealing topic for the scientific community due to the possibility of valorizing waste into an inexpensive, available, nontoxic, and renewable carbon feedstock. In this regard, last-generation heterogeneous catalysts are of great interest owing to their high catalytic activity, robustness, and easy recovery and recycling. In the present review, recent advances on CO 2 cycloaddition to epoxide mediated by hybrid catalysts through organometallic or organo-catalytic species supported onto silica-, nanocarbon-, and metal-organic framework (MOF)-based heterogeneous materials, are highlighted and discussed.

The Influence of Block Ionomer Microstructure on Polyplex Properties: Can Simulations Help to Understand Differences in Transfection Efficiency?

2017

Gene therapies enable therapeutic interventions at gene transcription and translation level, providing enormous potential to improve standards of care for multiple diseases. Nonviral transfection agents and in particular polyplexes based on block ionomers are-besides viral vectors and cationic lipid formulations-among the most promising systems for this purpose. Block ionomers combine a hydrophilic noncharged block, e.g., polyethylene glycol (PEG), with a hydrophilic cationic block. For efficient transfection, however, endosomolytic moieties, e.g., imidazoles, are additionally required to facilitate endosomal escape, which raises the general question how to distribute these functionalities …

Size‐Based Cationic Molecular Sieving through Solid‐State Nanochannels

2021

Advanced materials interfaces 8(6), 2001766 (2021). doi:10.1002/admi.202001766

Preparation and Properties of Ionic and Surface Modified Micronetworks

2007

Transient drift‐diffusion simulation of the open circuit voltage decay in ionic perovskite solar cells

2021

Pulsed laser deposition of Sr2FeMoO6 thin films

2005

Abstract The effect of various deposition conditions and after-growth protocols on the magnetic and transport properties of Sr 2 FeMoO 6 films has been explored. It is found that the saturation magnetization and the magnetoresistance (MR) are dominated by the degree of cationic order, and the strain effects are clearly evidenced in a lower T C . The after-growth annealing of the films and the deposition of a buffer layer has been found to relax the film strains. This translates into a clear increase of the measured low-field magnetoresistance ratios.

A local chemical potential approach within the variable charge method formalism

2008

A new and computationally efficient implementation of the variable charge method of Streitz and Mintmire (1994 Phys. Rev. B 50 11996) is presented. In particular a local chemical potential approach that optimizes the charge on only those atoms expected to be ionic is developed. By doing so, the charge fluctuation problem experienced in regions far from any oxygen is solved, leading to a linear minimization problem of the electrostatic energy. In the dilute oxygen limit, such an approach can lead to at least an order of magnitude saving in computation.