RHEOLASER LAB MICRORHEOLOGY & END USE PROPERTIES ANALYSIS. MICRORHEOLOGY

Transcription

1 RHEOLASER LAB & END USE PROPERTIES ANALYSIS

2 A NEW RHEOLOGY APPROACH TO CHARACTERISE END-USE PROPERTIES THE FIRST READY TO USE & END-USE PROPERTIES ANALYSER Rheolaser Rheolaser is the first Lab ready-to-use is the first instrument ready-touseinstrument experiments. to perform micro-rhe- to perform microrheology ology experiments. Microrheology is a new domain of Rheology, which characterises the structure of the material at the micron scale. Visco-elastic properties of soft materials such as emulsions, gels, polymers etc are analysed by measuring the displacement of the particles in the material due to the thermal energy (Brownian motion). RECOVERY SHAPE STABILITY DRUG DELIVERY TEXTURE STABILITY GELATION BENEFITS OF THE OPTICAL MICRO-RHEOMETER: Rheolaser has 1 to 6 measuring positions. The optical detection system uses Multi-Speckle Diffusing Wave Spectroscopy (MS-DWS). It measures interfering backscattering waves resulting from laser light multi-scattered by the particles. This accurate technique enables detection of small particle displacements. Particle mean square displacement data enables access to the microrheology parameters. ELASTICITY VISCOSITY KEY PARAMETERS IN 1-CLICK The measurement provides a viscoelastic signature of the product which is the MSD & 3 automatic parameters to quantify its end-use properties. MEAN SQUARE DISPLACEMENT (MSD) Visual signature of the product s viscoelasticity. => Compare qualitatively various products in a blink. NON CONTACT MEASUREMENT Measurement is performed without any external stress (thus always in the linear visco-elastic regime). It allows the analysis of fragile materials (weak gels, creams ) without sample modification nor destruction. MULTI APPLICATIONS The easy sample handling and automatic data processing enables different types of experiments to be carried out. Characterization at rest LIQUID SOLID SOLID-LIQUID BALANCE (SLB) Ratio between the solid-like and the liquid-like behaviour of the studied materials. => Monitor properties such as : adhesion, spreadability, gel point, shape stability, physical stability, etc... VISCOELASTIC PROPERTIES VS. TIME Measurement is performed in a glass cell: Structure recovery Gelation process Long-term stability... EASY SAMPLE HANDLING Measurement is performed in a glass cell: No sample deformation or destruction No evaporation or drying No geometry configuration Disposable measurement cell Evolution (gelation, melting...) Structure recovery & thixotropy Stability (vs. ageing time) MULTI DATA ANALYSIS The software has been designed for both experts and non experts in rheology with automated one-click results or fully configurable parameters. Mean Square Displacement (MSD) Solid-Liquid Balance (SLB) Elasticity Index (EI) STABLE ELASTICITY INDEX (EI) Elasticity strength in the studied materials. => Monitor properties such as : mesh/pore size, hardness, recovery after a shear, gelation... MACROSCOPIC VISCOSITY INDEX (MVI) Quantify and compare the macroscopic viscosity at zero-shear. Macroscopic Viscosity Index (MVI) Elastic & Viscous Moduli (G, G ) UNSTABLE => Monitor properties such as : effect of a thickening agent, texture, flowability, physical stability, etc... Physical parameters ( t R, D m, η )

3 APPLICATION FIELDS Cosmetic Paint & Ink Food Polymers... Pharmaceutical SPECIFICATIONS RHEOLASER LAB RHEOLASER LAB6 RHEOLASER LAB6+ Emission Detection Cell Volume Storage positions Simultaneous measurements Temperature range l* measurement Minimum Viscosity (mpa.s) Dimensions (cm) Weight (kg) Minimum PC configuration Recommended PC configuration Light source Light source Light source 650nm 650nm 650nm MS-DWS MS-DWS MS-DWS 4 or 20ml 4 or 20ml 4 or 20ml RT +5 C to 60 C RT +5 C to 60 C RT +5 C to 90 C No No Yes x40x30 36 Intel or AMD Processor 1 Gb Ram - Microsoft Windows XP Intel Dual or AMD X2 Processor 4 Gb Ram - Microsoft Windows XP, or 7, 32 bits Photo de couverture CNRS Photothèque - Billes de silices prises dans un polymère : A NEW WAY OF INVESTIGATING SOFT MATERIALS «Microrheology looks at the thermal motion of small particles embedded in a material in order to extract its bulk rheological properties. This experimental technique opens the investigation of material properties that are difficult to access or inaccessible by conventional rheology such as the visco-elastic response of fragile materials. It is a non-intrusive technique, and thus particularly well suited to study fragile materials such as weak gels (emulsions, yoghurts, cosmetics, ). No macroscopic stress is applied to the sample which avoids its destruction or its modification. This techniques increases our understanding of these materials. Annie Colin Rheologist Professor University of Bordeaux I Institut Universitaire de France 10, impasse Borde Basse L Union - France +33 (0)

4 DIFFUSING WAVE SPECTROSCOPY OPTICAL MEASUREMENT OF PARTICLES MOBILITY What is DWS? Diffusing Wave Spectroscopy is the dynamic Multiple Light Scattering measurement which tracks particle motion in a fluid. DWS is the Dynamic Light Scattering extended to opaque and concentrated media. EXPERIMENT SET UP LASER SCATTERING MS-DWS* Principle of Measurement MULTI-PIXEL DETECTOR MS-DWS consists in sending a coherent laser light beam into a sample. The light is multi-scattered by the particles, which leads to interfering backscattered waves. An interference image called Speckle image is detected by a multi-pixel detector. In a soft material, the thermal energy kbt leads to the motion of micron sized particles. PRINCIPLE OF MEASUREMENT LIGHT SOURCE SPECKLE IMAGE INTERFERING WAVES This Brownian motion induces a deformation of the speckle image. The multi-pixel detector measures the speckle pattern deformation to quantify motion speed of the particle. *Multi Speckle Diffusing Wave Spectroscopy BENEFITS OF MS-DWS Works on opaque and concentrated media Sensitive to small particle displacement (from 0,1 to 1000 nm) Access to microrheology parameters : - Viscosity - Elasticity - Relaxation time

5 MS-DWS PROCESSING SPECKLE IMAGE... MS-DWS AND PATENTED ALGORITHM + CORRELATION FONCTION PARTICLE MEAN SQUARE DISPLACEMENT (MSD) = Shear modulus = Thermal energy = Particle radius = Laplace frequency = Elastic modulus = Viscous modulus MS-DWS APPLICATIONS MS-DWS is a powerful multiple light scattering method to measure particle mobility. This technology is useful to analyse opaque and concentrated materials like concentrated emulsions, gels, polymers MS-DWS is used by: Rheolaser LAB to analyse the microrheology of soft materials GENERALISED STOKES EINSTEIN RELATION = Laplace transform of MSD Luca Cipelletti Professor Université de Montpellier Institut Universitaire de France measurements in the linear regime no wall slip issues samples contained in standard vials no need to transfer the sample nor to clean the rheometer tools fast measurements that allow the sample evolution to be monitored Multi-speckle Diffusing Wave Spectroscopy microrheology (MSDWS µrheology) is a recently introduced technique that greatly simplifies rheological measurements. No macroscopic deformation is applied to the sample. Instead, state-of-the-art optical techniques are used to measure the nanometer-scale motion of the sample constituents due to thermal energy. Rheological properties are deduced from this motion using a well-established formalism. Advantages of MS-DWS µrheology include: SLB, EI, MVI PATENTED ALGORITHM Rheolaser Horus to characterise film forming products (coatings, varnishes, cosmetic films ) 10, impasse Borde Basse L Union - France +33 (0)