Showing papers by "Florence Babonneau published in 2011"
TL;DR: This work proposes a broad reaction scheme and shows that, through HTC, it is possible to tune the furan-to-arene ratio composing the aromatic core of the produced HTC carbons, which is not possible if calcination is used alone, in the temperature range below 350 °C.
Abstract: The objective of this paper is to better describe the structure of the hydrothermal carbon (HTC) process and put it in relationship with the more classical pyrolytic carbons. Indeed, despite the low energetic impact and the number of applications described so far for HTC, very little is known about the structure, reaction mechanism, and the way these materials relate to coals. Are HTC and calcination processes equivalent? Are the structures of the processed materials related to each other in any way? Which is the extent of polyaromatic hydrocarbons (PAH) inside HTC? In this work, the effect of hydrothermal treatment and pyrolysis are compared on glucose, a good model carbohydrate; a detailed single-quantum double-quantum (SQ-DQ) solid state 13C NMR study of the HTC and calcined HTC is used to interpret the spectral region corresponding to the signal of furanic and arene groups. These data are compared to the spectroscopic signatures of calcined glucose, starch, and xylose. A semiquantitative analysis of t...
241 citations
TL;DR: In this paper, Zhao et al. used 13C and 15N solid state NMR to characterize nitrogen-containing hydrothermal carbons obtained from glucose and glycine, and they found an extended nitrogencontaining aromatic network, which is chemically bound to a polyfuran network known to be one of the main components of the biomass-derived HBCs.
Abstract: Here, 13C and 15N solid state NMR is used as the main and most effective characterization technique on nitrogen-containing hydrothermal carbons obtained from glucose and glycine. This study represents a model system for other types of nitrogen-containing hydrothermal carbons, which were shown to have interesting energy-storage properties (Zhao et al.Adv. Mater. 2010, 22, 5202). These materials are obtained either from N-containing carbohydrates or from pure carbohydrates in the presence of natural amino-containing compounds such as proteins or aminoacids. In contrast to what is generally known for this model system, high molecular weight heterogeneous polymers (e.g., melanoidins) that are formed when sugars and amino acids combine through the Maillard reaction, we found an extended nitrogen-containing aromatic network, which is chemically bound to a polyfuran network known to be one of the main components of the biomass-derived hydrothermal carbons. In contrast to the hydrothermal carbons obtained from pu...
92 citations
TL;DR: An original approach combining solid state NMR, molecular dynamics, first principles geometry optimization, and NMR parameters calculation allows the building of a precise representation of the organic/inorganic interface in liposils.
Abstract: In the context of nanomedicine, liposils (liposomes and silica) have a strong potential for drug storage and release schemes: such materials combine the intrinsic properties of liposome (encapsulation) and silica (increased rigidity, protective coating, pH degradability). In this work, an original approach combining solid state NMR, molecular dynamics, first principles geometry optimization, and NMR parameters calculation allows the building of a precise representation of the organic/inorganic interface in liposils. {1H–29Si}1H and {1H–31P}1H Double Cross-Polarization (CP) MAS NMR experiments were implemented in order to explore the proton chemical environments around the silica and the phospholipids, respectively. Using VASP (Vienna Ab Initio Simulation Package), DFT calculations including molecular dynamics, and geometry optimization lead to the determination of energetically favorable configurations of a DPPC (dipalmitoylphosphatidylcholine) headgroup adsorbed onto a hydroxylated silica surface that co...
67 citations
TL;DR: The different steps of the self-assembly in solution of several 2D-hexagonal silica nanostructured SBA-15 materials have been investigated by SAXS and SANS in situ experiments and unique quantitative information about the shape and size evolution upon time of the micellar aggregates throughout theself-assembly process is obtained.
Abstract: The different steps of the self-assembly in solution of several 2D-hexagonal silica nanostructured SBA-15 materials have been investigated by SAXS and SANS in situ experiments. Unique quantitative information about the shape and size evolution upon time of the micellar aggregates throughout the self-assembly process is obtained using a complete model that describes well the scattering data for the various synthesis conditions. In all cases, before the precipitation of the material, the micelles shape changes from spherical to rod-like, where the structure of the rod-like micelles is linked to the structure of the 2D-hexagonal precipitated material. In addition, the kinetics of hydrolysis of the inorganic precursor (TEOS) has been determined by in situ Raman spectroscopy. More specifically, by comparing synthesis made with different acids (HNO(3), HBr, HCl, H(2)SO(4), and H(3)PO(4)), it is found that materials prepared using the "salting-out" anions (SO(4)(2-) and H(2)PO(4)(-)) are much better ordered than with the "salting-in" anions (NO(3)(-) and Br(-)).
61 citations
TL;DR: This paper will focus on collagen and describe the process allowing to attain homogeneous fibrillar matrices, both at high concentrations and over long distances, and show that in vitro and in vivo studies validate these tissue-like constructs as repair materials for tissue engineering applications.
Abstract: Intermediate states of matter, in the form of liquid crystals, are indirectly evidenced in the body. Hence concepts developed by the soft matter community have allowed the highlighting of original morphogenetic pathways, strongly suggesting how 3D structures arise at the tissue level. The clues proposed have opened the way to reproduce biomimetic, hierarchically ordered, assemblies of biological macromolecules. The present paper will focus on collagen and describe the process allowing to attain homogeneous fibrillar matrices, both at high concentrations and over long distances. Their characterization at scales ranging from μm to cm will demonstrate suprafibrillar arrangements similar to dense connective tissues, with aligned or helicoidal geometries depending on the protein concentrations. In addition we will show that in vitro and in vivo studies validate these tissue-like constructs as repair materials for tissue engineering applications.
36 citations
TL;DR: In this paper, the synthesis of hybrid mesostructured silica from aqueous solutions of C12-Glutamic acid and C 12-Leucine based surfactant formulations with sodium silicate under neutral pH and atmospheric conditions is described.
Abstract: We report on the synthesis of hybrid mesostructured silica from aqueous solutions of C12-Glutamic acid and C12-Leucine based surfactant formulations with sodium silicate under neutral pH and atmospheric conditions. The approach shows the challenging task of organizing silica from entirely sustainable sources under environmentally benign conditions.
13 citations