Patrice Bacchin

Paul Sabatier University - Toulouse III | UPS Toulouse · Laboratoire de Génie Chimique - UMR 5503 - LGC

The purpose of this work is to examine the interplay between hydrodynamic conditions and physicochemical interactions from filtration experiments of microparticles. Experiments are performed in microfluidic filters with real time visualization at pore scale. Both flow rate and pressure are measured with time to analyse the dynamics of pore clogging...

We show that the solvent behaviour in both diffusio-osmosis and Marangoni flow can be derived from a simple model of colloid-interface interactions. We demonstrate that the direction of the flow is regulated by a single value of the attractive parameter covering the purely repulsive and attractive-repulsive interaction cases. The proposed universal...

Membrane fouling by proteins is an important problem in hemodialysis or hemofiltration (artificial kidney). The mechanisms leading to fouling are still not fully understood and then predictable. In this paper we describe a microfluidic chip fitted with a filtration membrane which allows the real time in situ fluorescent analysis of labelled protein...

This study reports the investigation of human serum albumin (HSA) adsorption on a poy-styrene-block–poly(acrylic acid) (PS-b-PAA)-coated PVDF membrane, which is a potential smart material for biomedical applications. First, copolymer coating on the membrane surface was successfully performed, due to the hydrophobic interaction of the PS anchoring g...

Non-electrolyte diffusiophoresis refers to the phenomenon where a particle in a solution moves in response to a gradient of non-ionic solute concentration. Although this phenomenon is commonly studied, most analyses assume either a negligible diffusive layer thickness or an infinite diffusion coefficient. In this research [1], we simulate diffusiop...

Recent advances have been made in coupling microfluidic chips with X-ray equipment, enabling structural analysis of samples directly in microfluidic devices. This important step mainly took place at powerful synchrotron facilities because of the need for a beam reduced in size to fit the microfluidic channel dimensions but still intense. In this wo...

Diffusiophoresis takes place when a particle in solution moves due to the presence of a solute concentration gradient. This phenomenon is often studied under some simplifying assumptions, such as negligible diffusive layer thickness or infinite diffusion coefficient. In this work we simulate diffusiophoresis without these simplifications. The goal...

Le terme « Matière molle » englobe la matière dont la structure, reposant sur des interactions de surface faibles, est très sensible aux sollicitations extérieures. De très nombreux procédés (filtration, séchage, …) sont amenés à jouer avec ces propriétés dans des domaines d’applications variés (agroalimentaire, environnement, chimie, …). Cette mat...

The dynamics of concentrated colloidal dispersion close to a phase transition are challenging to predict. The presence of attractive interactions leads to hindered motions through the change in transport properties such as collec- tive diffusion. We propose a continuum mechanical model to describe the dynamics of the relaxation of concentrated coll...

Diffusioosmosis, also referred to as capillary osmosis, is the flow of a solution relative to a fixed object, where the flow is driven by solute concentration gradient. The solution considered here is an aqueous mixture containing colloids that flows in a channel and through an array of cylinders, representing a membrane. In this work we use an ada...

In this comprehensive study, interaction of human serum albumin (HSA) with poly(acrylic acid) (PAA) was explored using Small Angle X-ray Scattering (SAXS) combined to chromatography. Results revealed the formation of a complex between HSA macromolecules and PAA chains but solely at some specific conditions of ionic strength and pH of the medium. In...

Diffusio-phoresis is the move of a particle in a solute or in a colloid concentration gradient. It will be shown that the diffusio-phoresis can be seen of a result of local Marangoni and osmotic flows around the particle. The transport of a particle by diffusio-phoresis can then be related to the interaction between the colloids and the particles....

Dans de très nombreux procédés, le transport aux interfaces joue un rôle important. C’est notamment le cas dans les procédés membranaires ou dans des dispositifs microfluidiques où des particules de petites tailles (nanoparticules, colloïdes, émulsion, cristaux ou plus généralement la matière molle) sont amenées dans des milieux très contraints (po...

Polymer blend made from poly(ε - caprolactone)/chitosan (PCL/CHT) offers interesting opportunities for biological applications. The paper presents a new way to fabricate PCL/CHT double-porosity (macrovoids with interconnected microporosity) membrane materials from a chemical optimization of the solvent and non-solvent phases and from a modified pha...

In this paper, we developed membrane scaffolds to mimic the biochemical and biophysical properties of human mesenchymal stem cell (hMSC) niches to help direct self-renewal and proliferation providing to cells all necessary chemical, mechanical and topographical cues. The strategy was to create three-dimensional membrane scaffolds with double porosi...

Flow through channels is a common process in living bodies (kidneys, membrane cells, etc.), in natural systems (aquifers) and in industrial applications (filtration, desalting, etc.). However, the transport mechanisms of particles and cells in such systems and the associated clogging events are still unpredictable. The aim of this seminar is to pr...

Talk in the session Interfacial Soft Matter at 10:30 the 6th June 2019 at Edinburgh

Hemodialysis is an important therapy for treating patients with End Stage Renal Disease (ESRD). These patients visit the hospital 3 times a week and each time their blood is cleansed during 4-hour dialysis sessions using a hollow fiber membrane module; also called artificial kidney. This device mainly achieves removal of small water-soluble toxins...

One of the major challenges of tissue-engineered small diameter vascular graft is to determine their healing efficiency via measuring hydraulic resistance constituted by the endothelium. There is a need for experimental models that allow controlled studies of tissue engineering strategies. Organs-on-chips have recently emerged as in vitro models th...

This presentation at the Groupement De Recherche SLAMM http://slamm.cnrs.fr (Solliciter la Matière Molle) à Hyères will show how interfaces in colloidal dispersion can drive flow. A theoretical approah will be proposed to depict these phenomena and will allow to unify the description of osmotic and Marangoni flows. 2D Simulations will be presented...

The aim of this seminar will be to show how membrane/colloid and colloid/colloid interactions play an important role in the transport of colloids across a membrane. From an experimental point of view, we will see how microfluidics tools can help to understand the formation of clogs at the level of a pore bottleneck and how this formation depends on...

L'intervention présente les enjeux de la troisième industrielle (3RI) ainsi que les piliers sur lequel s'appuie son développement dans la société et dans l’industrie. Les freins à son développement en Europe seront également discutés et un projet de l'université pour le développement de la 3RI à Madagascar illustrera les possibilités de développeme...

Blockage of pores by particles is found in numerous industrial and natural processes, including filtration and oil extraction. We present experimental results of filtration through a linear array of ten channels with one dimension which is sub-micron. These silicon-glass nanoslits serve as model pores, through which a dilute dispersion of Brownian...

The drying of complex fluids provides a powerful insight into phenomena that take place on time and length scales not normally accessible. An important feature of complex fluids, colloidal dispersions and polymer solutions is their high sensitivity to weak external actions. Thus, the drying of complex fluids involves a large number of physical and...

An artificial vascular patch of poly (ε-caprolactone) (PCL) and Chitosan (CHT) blend membrane have been developed to mimic a three dimensional bio-architecture with double porous morphology : (i) surface macrovoids that could be easily accessible for cell proliferation and differentiation; (ii) macroporous spongy network to transfer essential nutri...

Membranes are often merely reduced to their 2D properties (surface area, surface porosity, pore size). However, when trying to biomimic the transport efficiency of biological channels (such as aquaporin), the importance of the interaction across the third dimension (i.e. along the pore) becomes obvious. In addition, the elaboration of membranes hav...

When colloids flow in a narrow channel, the transport efficiency is controlled by the non-equilibrium interplay between colloid-wall interactions and hydrodynamics. In this paper, a general, unifying description of colloidal dispersion flow in a confined system is proposed. A momentum and mass balance founded framework implementing the colloid-inte...

Organs-on-chips are microfluidic cell culture systems that allow studies of cell-cell interactions and functional analysis of cultured tissues. When cell monolayers like endothelium or epithelium are cultured in organs-on-chips, one of the key aspects to evaluate is barrier function. Methods to evaluate barrier function in organs-on-chips are chara...

Présentation des bases de Python pour le calcul scientifique appliqué au génie des procédés

A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances in the membrane energy landscape establishes a new way of writing for the Darcy law. The counter-pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather...

When colloids flow in a narrow channel, the transport efficiency is controlled by the non-equilibrium interplay between colloid-wall interactions and hydrodynamics. In this paper, a general, unifying description of colloidal dispersion flow in a confined system is proposed. A momentum and mass balance founded framework implementing the colloid-inte...

When colloids flow in a narrow channel, the transport efficiency is controlled by the non-equilibrium interplay between colloid-wall interactions and hydrodynamics. In this paper, a general, unifying description of colloidal dispersion flow in a confined system is proposed. A momentum and mass balance founded framework implementing the colloid-inte...

A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances on the membrane energy landscape establishes a new way of writing for the Darcy law. The counter pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather...

In the presentation, it will be discussed how specific solute-membrane interaction can change the membrane transfer properties (in term of selectivity and productivity). Theoretical developments using a two fluid approach will enable the description of the transport of water and of solute on an energy landscape. These developments will allow to det...

The present study is aimed at shedding light on the transport mechanisms involved in a functionalized membrane designed for improving hemodialysis. This membrane has been prepared by embedding absorptive micro particles within its porous structure. To achieve this, a mathematical model coupling convection, diffusion and adsorption is developed and...

A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances on the membrane energy landscape establishes a new way of writing for the Darcy law. The counter pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather...

Living particles such as bacteria are able to transfer through membrane pores that are smaller than cell size due to the specific stiffness of this type of microorganism. This phenomenon can lead to a significant loss of selectivity in the filtration process, which is a major cause of concern in the sterilizing filtration step. This study investiga...

Flows of concentrated colloidal suspensions may exhibit a rich set of behaviors due to both hydrodynamic and colloidal interactions between the particles. Colloidal flows are generally modeled with an effective Navier–Stokes equation and a mass balance for the solid phase involving a diffusion coefficient given by the generalized Stokes–Einstein re...

Clogging of channels by complex systems such as mixtures of colloidal and biological particles is commonly encountered in different applications. In this work, we analyze and compare the clogging mechanisms and dynamics by pure and mixture suspensions of polystyrene latex particles and Escherichia coli by coupling fluorescent microscopic observatio...

Chylothorax is an uncommon form of pleural effusion, which generally occurs after cardiac surgery and almost any surgical operation in the chest. The aim of this project is to develop a bioresorbable vascular patch for lymphatic wall repair [1]. Here, we project to develop new materials (i.e. membranes) having two different levels of porosity [2]....

A polymeric catalytic membrane was previously prepared that showed remarkable efficiency for Suzuki-Miyaura C-C cross-coupling in a flow-through configuration. A mathematic model was developed and fitted to the experimental data to understand the significant apparent reaction rate increase exhibited by the catalytic membrane reactor compared to the...

Transport and deposition of microparticles in porous media is of primary importance in filtration and membrane processes. The presentation will analyze the clogging behavior of microparticles during microfluidics filtration experiments. A dispersion of microparticles having three well different interaction profiles (high potential barrier, secondar...

A two fluid model (for the dispersed –particle or solute- and the solvent phases) will be presented and applied to the modeling of the transfer through a membrane or a filter. Such a model is coupled with an energy map describing the impact of the membrane on transfer and selectivity. Such a model allows to describe with a same set of equation (a...

The purpose of this work is to examine the interplay between hydrodynamic conditions and physicochemical interactions from filtration experiments of microparticles. Experiments are performed in microfluidic filters with real time visualization at pore scale. Both flow rate and pressure are measured with time to analyse the dynamics of pore clogging...

Nano-particles in suspension often experience strong non-hydrodynamic interactions (NHIs) such as electrostatic repulsions. In this work, we present and justify a flow modeling strategy adapted to such systems. Earlier works on colloidal transport in simple flows, were based on the solution of a transport equation for the colloidal volume fraction...

Microfluidic devices with a network of micrometric channels mimicking membrane microfiltration are fabricated with NOA (Norland Optical Adhesive) on a glass slide by using soft lithography and replica molding techniques. These systems allow the direct microscopic observation of pore clogging during constant flux and constant pressure filtrations of...

Microfluidic devices with a network of micrometric channels mimicking membrane microfiltration are fabricated with NOA (Norland Optical Adhesive) on a glass slide by using soft lithography and replica molding techniques. These systems allow the direct microscopic observation of pore clogging during constant flux and constant pressure filtrations of...

The aim of this work is to study the pore blocking by the use of microfluidic devices (micro-separators) and numerical simulation approaches. The micro-separators are made in PDMS and are constituted of an array of microchannels 20 micrometers wide with three types of structure: straight microchannels, connected microchannels (or aligned square pil...

The purpose of this work is to depict pore clogging occurring when filtering colloids. Direct numerical simulations of the coupled motion of particles and fluid have been performed with the Force Coupling Method (FCM)1 to investigate the dynamics of colloids accumulation at a pore entrance. The geometry has been chosen to match experiments realised...

Based on direct numerical simulations of the coupled motion of particles and fluid, this study analyzes the collective hydrodynamic and colloidal effects of flowing microparticles during the formation of different 3D clogging patterns at a pore entrance. Simulations of flowing suspensions through a pore with various simulation conditions show that...

The work presented in this thesis for the French degree of Habilitation à Diriger des Recherches is on the border between soft-matter physics and chemical engineering and uses physics to develop and give a scientific basis to new concepts and tools for the engineer. In the case of membrane colloid filtration which constitutes the major part of this...