Platform 1 - Microscopy, Materials and Physicochemistry

The technical plateform « Microscopy, Materials and Physicochemistry" combines technical skills of FARE in physicochemistry, implementation of composite materials, preparation of nanostructured assemblies, microscopy, spectroscopy, modeling of the deconstruction of lignocelluloses, and image processing. The know-how contribute to studies of the properties of lignocelluloses and the mechanisms of their transformation. They are also used for researches on the new functional properties of materials and nano and macro-structured objects designed in the Unit. The modeling tools allow the development of dynamic approaches at different spatial and temporal scales for lignocelluloses transformation process. 

● Physicochemistry of lignocelluloses, polymers and nanostructured assemblies :

The technical plateform includes techniques for the preparation and characterization of lignocellulosic walls, their fractions or polymers, and assembly methods of fractions and polymers at nanometric and micrometric scales.

Preparation of lignocelluloses, polymers and nanostructured assemblies :
* Techniques of preparation plant walls and lignocellulosic fractions; chemical and thermal pretreatments (acid, chlorite, hydrothermal, ionic liquid)
* Extraction and purification of lignocellulosic polymers (nanocrystals or nanofibrils cellulose, hemicelluloses, lignins)
* Synthesis of lignin models (DHP G et G/S)
* Development of nanostructured assemblies of lignocellulosic polymers, bioinspired of plant cell wall with controlled thickness (monolayer to multilayers, films, gels) using different processes : Langmuir-Blodgett, spin-coating, casting (static/dynamic), phase diagram.

Chemical characterization of lignocelluloses, polymers and nanostructured assemblies
* Chemical hydrolysis, separation methods (HPLC, GC) and gravimetric methods ;
* Spectroscopies (mid and near-InfraRed, fluorescence, UV/Visible, Nuclear Magnetic Resonance HSQC 1H NMR, 13C, 31P NMR).

Physicochemical characterization of lignocelluloses, polymers and nanostructured assemblies
* Analysis of polymers by size exclusion chromatography, light scattering (MALLS, QELS);
* Water sorption isotherm by standard dynamic vapor sorption (DVS) microbalance and for high samples troughput;
* Characterizations of layers and thin films :
       - Measurement of thicknesses and refractive index by spectroscopic ellipsometry and surface plasmon resonance (MP-SPR)
       - Contact angle measurement (Goniometer, Tracker)
       - Measurement of surface properties of molecules or polymers at fluid interfaces air/liquid, liquid/liquid, liquid/solid (tensiometer Tracker)
       -Measurement of molecular interactions (affinity constants, adsorption kinetics), swelling and voltammetry on thin layers of polymers by surface plasmon resonance (MP-SPR).

Functional properties of lignocelluloses, polymers and nanostructured assemblies
* Measurement of properties (antioxidant, antimicrobial, gas barriers) in solution and in nanostructured assemblies.

● Materials :

The tools and techniques allow the design, formulation and characterization of biosourced composite materials, based on different plant constituents (polymers and plant fibers) :

Formulation :
* Extrusion : single screw and twin screw
* Internal mixer (Batch)
* Mini-injection press
* Plate press

Characterization :
* Rheologie;
* Thermal and thermomechanical analysis by thermogravimetric analysis (ATG) ;                                 * Characterization by dynamic mechanical analysis (DMA);
* Characterization and measurement of O2 barrier properties by differential scanning calorimetry (DSC);
* Mechanical properties by traction, microtraction in a controlled environment;                                   * Morphological analysis, profilmeter;
* Measurement of interactions with steam, density measurements under argon by standard or high-throughput DVS gravimetric analysis.

● Microscopy :

The microscopy methods include the preparation of samples (wood fragments, grass stems, fibers) and their analyses, using fluorescence, immunocytochemistry and microspectrophotometry techniques to study the architecture of tissues and wall polymers.

Imaging and analysis :

* Microscopy and macroscopy imaging (visible and fluorescence);
* Polarization microscopy analysis;
* Imaging and measurements of dynamics (mobilities, accessibility, interactions) by fluorescence recovery after photobleaching (FRAP), fluorescence lifetime measurement (FLIM) and resonance energy transfer (FRET) of fluorescent probes in confocal microscopy of fluorescence;
* 4D fluorescence imaging (time and space) with temperature control;
* Quantification of fluorescence intensity and sample morphology at the cellular scale                      * BIOMODLAB : a modular, user-friendly and open source software platform that integrates both image processing tools to analyze 4D data (space + time) and tools to analyze and model biophysical and biochemical processes.