Publiée 5 août 2026
Thèse CIFRE NR
Michelin
Clermont-Ferrand, Auvergne-Rhône-Alpes 63000, France
CDI
Thèse CIFRE NR
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2. Research Objectives
Objective 1 - Laboratory-scale characterization of latex viscoelastic and interfacial properties
Objective 2 - Rheofluidics-based microfluidic methodology development
Objective 3 - Field implementation and technology transfer
3. Methodology
Phase 1 - Laboratory Characterization and Rheofluidics Calibration (M1-12)
Experiments will be conducted jointly by IPGG (Fattaccioli lab, ENS/Sorbonne Université) and ESPCI (Aimé lab, UMR C3M). Rheofluidics setups will first be calibrated on PEO solutions spanning a wide G'(ω)/G''(ω) range, cross-validated against bulk oscillatory rheology. Ammonia-stabilized latex will then be introduced as monodisperse droplets in a viscosity-tuned oil phase to prevent clogging and to shift the measurement frequency window. Dynamic interfacial tension will be extracted by droplet relaxation; viscoelastic moduli by Rheofluidics. Pendant drop tensiometry on the same batches will establish the quantitative relationship between the latex-in-oil microfluidic observable and the latex-serum interfacial tension relevant to field conditions.
Structural and physicochemical characterization of latex - particle size distribution by centrifuge particle sedimentation (CPS), polyisoprene chain length by SEC, and particle morphology by SEM and AFM - will be performed by the PhD candidate at Michelin (Clermont-Ferrand), leveraging the analytical infrastructure available at the industrial partner. These datasets will be systematically correlated with the single-droplet Rheofluidics observables, establishing the quantitative link between latex composition/structure and its interfacial and viscoelastic properties.
Phase 2 - Destabilization Studies and Frequency Window Engineering (M13-24)
Progressive pH reduction will drive latex toward aggregation; G'(ω), G''(ω), and interfacial tension will be tracked to define the diagnostic sensitivity of Rheofluidics readouts and threshold values predictive of flow instability. In parallel, oil viscosity formulations will be optimized systematically to map the operating envelope of the portable setup, reducing framerate and magnification requirements. A stroboscopic acquisition scheme - low-cost CMOS camera with synchronized illumination - will be developed as an alternative to high-speed cameras, a key enabler for cost-effective field replication.
Phase 3 - Portable Device Development and Field Validation (M19-36)
The portable device will be built around pressure-driven flow actuation and a compact CMOS brightfield module. Glass/FLAE chips (FemtoPrint) will be used for the first validated field campaigns; geometry will subsequently be transferred to thermoplastic COC/COP chips produced by hot embossing at IPGG for routine deployment, batch-producible and disposable. All chip formats will be cross-validated against the PDMS rheofluidics reference using PEO standards before each field campaign. Field measurements will target at least two tapping season campaigns at SAPH-Toupah (Ivory Coast), with data also assessed against Michelin's incoming quality control specifications.
The project benefits from the support of the IPGG Microfabrication Platform for three core capabilities: (i) glass microfabrication by laser-induced wet etching (LIDE/FLAE), developed over the last two years; (ii) automated droplet production with real-time size tracking and pressure feedback; (iii) injection mold fabrication and small-series plastic chip production, developed in partnership with an industrial plastics manufacturer under an Île-de-France regional pre-industrialization grant.
4. Expected Outcomes
Scientific contributions
Technological deliverables
Industrial impact
Improved consistency and quality of latex production, with reduced coagulation-related losses. A potential integration pathway into Michelin's supplier quality control chain, extending from plantation-level monitoring to incoming material inspection at Clermont-Ferrand.
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Michelin, entreprise engagée dans la mobilité durable et reconnue pour ses actions en faveur de l'expérience employé !
Pour en savoir plus sur le Groupe :https://recrutement.michelin.fr
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2. Research Objectives
Objective 1 - Laboratory-scale characterization of latex viscoelastic and interfacial properties
- Measure dynamic interfacial tension of ammonia-stabilized latex by droplet relaxation microfluidics, cross-validated against pendant drop tensiometry.
- Quantify frequency-dependent viscoelastic moduli G'(ω) and G''(ω) by Rheofluidics as a function of pH, ammonia content, and time-from-tapping.
- Structural and physicochemical characterization of latex - particle size distribution (CPS), polyisoprene chain length (SEC), particle morphology (SEM/AFM) - performed by the PhD candidate at Michelin (Clermont-Ferrand), and correlated with single-droplet observables.
Objective 2 - Rheofluidics-based microfluidic methodology development
- Design and optimize chip geometries (sinusoidal constriction channels, flow-focusing junctions) for latex-in-oil emulsions with viscosity-tuned continuous phases (Aiglon oil-soluble viscosifiers).
- Calibrate rheofluidics against bulk oscillatory rheology using PEO standards across a wide G'/G'' range.
- Engineer the accessible measurement frequency window through oil viscosity modulation, mapping the operating envelope as a function of viscosity and channel wavelength - enabling compatibility with low-cost CMOS imaging and stroboscopic acquisition.
- Investigate pH-induced destabilization to define diagnostic thresholds predictive of flow instability.
Objective 3 - Field implementation and technology transfer
- Translate the laboratory platform into a portable, pressure-driven Rheofluidics device following a two-stage chip fabrication strategy: glass chips by femtosecond laser-assisted wet etching (FLAE, FemtoPrint) for initial validated field campaigns, followed by thermoplastic chips (COC/COP, hot embossing at IPGG) for batch-producible routine deployment.
- Validate the device at SAPH-Toupah plantation (Côte d'Ivoire) over at least two tapping season campaigns.
- Assess applicability to Michelin's quality monitoring of incoming natural rubber at Clermont-Ferrand.
3. Methodology
Phase 1 - Laboratory Characterization and Rheofluidics Calibration (M1-12)
Experiments will be conducted jointly by IPGG (Fattaccioli lab, ENS/Sorbonne Université) and ESPCI (Aimé lab, UMR C3M). Rheofluidics setups will first be calibrated on PEO solutions spanning a wide G'(ω)/G''(ω) range, cross-validated against bulk oscillatory rheology. Ammonia-stabilized latex will then be introduced as monodisperse droplets in a viscosity-tuned oil phase to prevent clogging and to shift the measurement frequency window. Dynamic interfacial tension will be extracted by droplet relaxation; viscoelastic moduli by Rheofluidics. Pendant drop tensiometry on the same batches will establish the quantitative relationship between the latex-in-oil microfluidic observable and the latex-serum interfacial tension relevant to field conditions.
Structural and physicochemical characterization of latex - particle size distribution by centrifuge particle sedimentation (CPS), polyisoprene chain length by SEC, and particle morphology by SEM and AFM - will be performed by the PhD candidate at Michelin (Clermont-Ferrand), leveraging the analytical infrastructure available at the industrial partner. These datasets will be systematically correlated with the single-droplet Rheofluidics observables, establishing the quantitative link between latex composition/structure and its interfacial and viscoelastic properties.
Phase 2 - Destabilization Studies and Frequency Window Engineering (M13-24)
Progressive pH reduction will drive latex toward aggregation; G'(ω), G''(ω), and interfacial tension will be tracked to define the diagnostic sensitivity of Rheofluidics readouts and threshold values predictive of flow instability. In parallel, oil viscosity formulations will be optimized systematically to map the operating envelope of the portable setup, reducing framerate and magnification requirements. A stroboscopic acquisition scheme - low-cost CMOS camera with synchronized illumination - will be developed as an alternative to high-speed cameras, a key enabler for cost-effective field replication.
Phase 3 - Portable Device Development and Field Validation (M19-36)
The portable device will be built around pressure-driven flow actuation and a compact CMOS brightfield module. Glass/FLAE chips (FemtoPrint) will be used for the first validated field campaigns; geometry will subsequently be transferred to thermoplastic COC/COP chips produced by hot embossing at IPGG for routine deployment, batch-producible and disposable. All chip formats will be cross-validated against the PDMS rheofluidics reference using PEO standards before each field campaign. Field measurements will target at least two tapping season campaigns at SAPH-Toupah (Ivory Coast), with data also assessed against Michelin's incoming quality control specifications.
The project benefits from the support of the IPGG Microfabrication Platform for three core capabilities: (i) glass microfabrication by laser-induced wet etching (LIDE/FLAE), developed over the last two years; (ii) automated droplet production with real-time size tracking and pressure feedback; (iii) injection mold fabrication and small-series plastic chip production, developed in partnership with an industrial plastics manufacturer under an Île-de-France regional pre-industrialization grant.
4. Expected Outcomes
Scientific contributions
- First single-droplet dataset of G'(ω), G''(ω), and dynamic interfacial tension of natural rubber latex as a function of pH, ammonia content, and time-from-tapping.
- Quantitative characterization of the dependence of latex interfacial and viscoelastic properties on structural and physicochemical composition (particle size distribution, polyisoprene chain length, particle morphology).
- Novel rheofluidics-based microfluidic methodologies tailored to time-evolving colloidal suspensions, with broad applicability beyond latex.
- A diagnostic framework correlating microfluidic single-droplet observables with latex quality indicators.
Technological deliverables
- A portable rheofluidics device enabling real-time, on-site measurement of latex viscoelastic and interfacial properties - directly deployable on plantations and at industrial receiving stations.
- COC/COP thermoplastic chip production process, validated for batch-producible disposable deployment without clean room infrastructure.
- A validated measurement protocol applicable to Michelin's quality monitoring of incoming natural rubber, providing actionable metrics to reduce batch variability.
Industrial impact
Improved consistency and quality of latex production, with reduced coagulation-related losses. A potential integration pathway into Michelin's supplier quality control chain, extending from plantation-level monitoring to incoming material inspection at Clermont-Ferrand.
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Michelin, entreprise engagée dans la mobilité durable et reconnue pour ses actions en faveur de l'expérience employé !
- Une note de 99/100 à l'index de l'égalité femmes-hommes
- Entreprise « Handi accueillante », avec un réseau de référents et ambassadeurs Handicap pour vous accompagner
- 83,5% de taux d'engagement de nos employés
- 94,6% des stagiaires et alternants nous recommandent, label "Happy Trainees" depuis 9 années consécutives
- Classé parmi les groupes du CAC 40 les plus engagés selon les Bac+5 à l'index RSE Universum 2023
- Parmi les 100 entreprises les plus attractives pour les étudiants et actifs BAC+2/3 au classement Universum 2023
- N°1 des entreprises de plus de 500 stagiaires et alternants qui rémunèrent le mieux au Classement HappyTrainees® Rémunération 2023
- Dans le Top 10 des meilleurs employeurs en France au classement Glassdoor 2023
- Dans le top 3 des entreprises du secteur « Automobile / Equipementier » en matière d'attractivité employeur à l'édition 2024 du Palmarès @EPOKA @GROUPE IFOP @Occurrence
Pour en savoir plus sur le Groupe :https://recrutement.michelin.fr
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