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2. Thickness-dependent microstructural and electromechanical properties in polyurethane films obtained by polymer solution casting

Author

Wongtimnoi, K., Cavaillé, J.-Y., Chenal, J.-M., Guiffard, B., Bogner, A., Seveyrat, L., Laboratoire de Génie Electrique et Ferroélectricité (LGEF), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Burapha University (BU), ELyTMaX, École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Tohoku University [Sendai]-Centre National de la Recherche Scientifique (CNRS), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées de Lyon, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
[SPI]Engineering Sciences [physics]
Abstract

International audience; Electroactive polymers (EAPs) are promising materials for actuation and energy harvesting applications. Among the EAPs, polyurethane (PU) material is of considerable interest given its high values of deformation under an electric field. The electromechanical properties were found to be dependent on the processing technique and the thickness of the film. To understand this relationship, a comprehensive study was carried out on polyether-based thermoplastic PU elastomer films elaborated by solution casting with thicknesses between 12 and 220 μm. Microstructural, dielectric, mechanical, and electrostriction studies were conducted. Thin films present a lower strain for a given electric field compared to thick films. The films exhibit a structural gradient along the thickness direction: a fast evaporation in the upper part of the film close to the interface with air inhibits the phase separation but a more favored one in the lower part. This is consistent with the modeling based on the gradient of dielectric constant and the experimental, mechanical, and dielectric characterizations.

Published
2019

3. About the Influence of Materials Parameters on the Ultimate and Fatigue Properties of Elastomers.

Author

Chazeau, L., Chenal, J.-M., Gauthier, C., Kallungal, J., and Caillard, J.

Subjects
*CRACK propagation (Fracture mechanics), *FRACTURE mechanics, *ELASTOMERS, *FATIGUE crack growth, *PREMATURE rupture of fetal membranes, *ECCENTRIC loads
Abstract

The aim of this chapter is to revisit the historical works, mechanisms, and modeling approaches available in the field of fatigue crack growth resistance and rupture properties. After introducing the methodology developed to evaluate these properties, the impact of testing parameters such as temperature, loading speed, and pre-deformation will be highlighted. We will then review the influence of some material characteristics on rupture and crack propagation and the local mechanisms involved. Finally, a theoretical framework primarily dedicated to the description of crack propagation under static load will be discussed that aims to underline the connection between resistance to crack growth and the ability of a material to dissipate energy. [ABSTRACT FROM AUTHOR]

Published
2021
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4. Effect of ageing and annealing on the mechanical behaviour and biodegradability of a poly(3-hydroxybutyrate) and poly(ethylene-co-methyl-acrylate-co-glycidyl-methacrylate)blend

Author

Kurusu, R.S., Demarquette, N.R., Gauthier, C., Chenal, J.-M., Matériaux, ingénierie et science [Villeurbanne] ( MATEIS ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
PHB, education, [ SPI.MAT ] Engineering Sciences [physics]/Materials, technology, industry, and agriculture, Mechanical properties, Small angle X-ray scattering, Mechanical behaviour, Blending, Microbiology, [SPI.MAT]Engineering Sciences [physics]/Materials, Annealing, Scattering, Ethylene, Ageing, Differential scanning calorimetry, Reactive blends, Biodegradation, Biodegradation in soil, Crystalline structure, Poly(3-hydroxybutyrate)
Abstract

cited By 10; International audience; Poly(3-hydroxybutyrate) (PHB) undergoes an ageing process that contributes to its remarkable fragility. Blending it with an elastomer is a possibility to increase toughness. In this work, the mechanical properties of a 70/30wt% blend of PHB and poly(ethylene-co-methyl-acrylate-co-glycidyl-methacrylate) were studied over time. The phenomenon of ageing affected the blend, which lost its ductility and became fragile days after its processing. Differential scanning calorimetry and small angle X-ray scattering analyses showed that this drop in mechanical properties was due to changes in the crystalline structure of the matrix. Annealing reduced fragility, increased toughness and prevented a re-ageing of the blend. Biodegradation in soil was also more intense for annealed samples. © 2013 Society of Chemical Industry.

Published
2014

5. Supramolecular Chemistry for Pressure Sensitive Adhesives ?

Author

Callies, Xavier, Fonteneau, Cécile, Vechambre, Cyril, Pensec, Sandrine, Bouteiller, Laurent, Ducouret, Guylaine, Creton, Costantino, Chenal, J.-M., Chazeau, Laurent, Sciences et Ingénierie de la Matière Molle (SIMM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), Sorbonne Université (SU), ANR-10-BLAN-0801,Supradhésion,Adhésion supramoléculaire(2010), Callies, Xavier, BLANC - Adhésion supramoléculaire - - Supradhésion2010 - ANR-10-BLAN-0801 - BLANC - VALID, Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.POLY]Chemical Sciences/Polymers, [CHIM] Chemical Sciences, [CHIM]Chemical Sciences, [CHIM.MATE]Chemical Sciences/Material chemistry
Abstract

International audience; Pressure Sensitive Adhesives (PSA) are soft polymer materials which stick on almost any surface due to their particular rheological properties. Engineers adjust polymers molecular structure to optimize adhesion properties for each application. The nature of the monomers, molecular weight distribution and degree of crosslinking are classical tunable parameters for acrylic adhesives. The specificity of our project is to improve the adhesive properties of acrylic model polymers by incorporating bis-urea monomers. The presence of strong hydrogen bonds inside the polymeric matrix allows to dramatically increase the viscosity and dynamic modulus of short polymer chains (M

Published
2013

6. In situ WAXS dynamic study of strain induced crystallization kinetics of synthetic and natural rubber

Author

Candau, N., Laurent CHAZEAU, Chenal, J. -M, Gauthier, C., Munch, E., Thiaudiere, D., Matériaux, ingénierie et science [Villeurbanne] ( MATEIS ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ), Institut Charles Sadron ( ICS ), Université de Strasbourg ( UNISTRA ) -Centre National de la Recherche Scientifique ( CNRS ) -Matériaux et nanosciences d'Alsace, Université de Strasbourg ( UNISTRA ) -Université de Haute-Alsace (UHA) Mulhouse - Colmar ( Université de Haute-Alsace (UHA) ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ) -Université de Haute-Alsace (UHA) Mulhouse - Colmar ( Université de Haute-Alsace (UHA) ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Réseau nanophotonique et optique, Université de Strasbourg ( UNISTRA ) -Université de Haute-Alsace (UHA) Mulhouse - Colmar ( Université de Haute-Alsace (UHA) ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Strasbourg ( UNISTRA ), Manufacture Française des Pneumatiques MICHELIN, Société Michelin, Synchrotron SOLEIL ( SSOLEIL ), Centre National de la Recherche Scientifique ( CNRS ), GilNegrete, N and Alonso, A, Mateis, Laboratoire, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), GilNegrete, N and Alonso, Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[ SPI.MAT ] Engineering Sciences [physics]/Materials, [SPI.MAT] Engineering Sciences [physics]/Materials, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

8th European Conference on Constitutive Models for Rubbers (ECCMR), Univ Navarra, CEIT Tecnun, San Sebastian, SPAIN, JUN 25-28, 2013; International audience; Real time Wide-Angle X-ray Scattering (WAXS) measurements during cyclic tensile tests at high strain rates (from 8 s(-1) to 280 s(-1)) and at room temperature on crosslinked Natural Rubber (NR) and Synthetic Rubber (IR) are performed thanks to the development of a specific homemade device. From the observed influence of the frequency on the crystallization index at the maximum sample elongation, a characteristic crystallization time is deduced. Furthermore, an adjustable stroboscopic system allows obtaining the crystalline properties not only at the maximum sample elongation but along the complete cycle. The experiments enabled us to extract a critical time of 50 msec below which the macromolecules cannot appreciably crystallize. A comparative study on NR and IR shows that these materials exhibit very similar strain-induced crystallization kinetics. This trend is very different than these one observed during conventional test, i.e. at law strain rate. These results should be explained by the high degree of supercooling reached by both materials.

Published
2013

7. Influence of the rubbery phase on the crystallinity and thermomechanical properties of poly(3-hydroxybutyrate)/elastomer blends

Author

Calvão, P.S., Chenal, J.-M., Gauthier, C., Demarquette, N.R., Dos Santos, A.M., Cavaille, J.Y., Matériaux, ingénierie et science [Villeurbanne] ( MATEIS ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ), inconnu, Inconnu, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
nucleation, Processability, [ SPI.MAT ] Engineering Sciences [physics]/Materials, Mechanical properties, thermal property, Processing Route, Processing, [SPI.MAT]Engineering Sciences [physics]/Materials, Processing method, Thermomechanical properties, Ethylene, Plasticizers, Polymer blends, biopolymer, Fracture mechanics, Crystallinities, Nucleating effect, glass transition temperature, physical property, crystallinity, elastomer, Amorphous phase, temperature, polymer blend, Ethylene propylene diene terpolymer, Polyvinyl butyral, Superconducting transition temperature, mechanical property, Reinforced plastics, Crystallization temperature, Propylene, Glass, Rubber, Crystallization, Glass transition, Poly(3-hydroxybutyrate), Melt processing
Abstract

cited By 16; International audience; Poly(3-hydroxybutyrate) (PHB) is a very promising biopolymer. In order to improve its processability and decrease its brittleness, PHB/elastomer blends can be prepared. In the work reported, the effect of the addition of a rubbery phase, i.e. ethylene-propylene-diene terpolymer (EPDM) or poly(vinyl butyral) (PVB), on the properties of PHB was studied. The effects of rubber type and of changing the PHB/elastomer blend processing method on the crystallinity and physical properties of the blends were also investigated. For blends based on PHB, the main role of EPDM is its nucleating effect evidenced by a decrease of crystallization temperature and an increase of crystallinity with increasing EPDM content regardless of the processing route. While EPDM has a weak effect on PHB glass transition temperature, PVB induces amarked decrease of this temperature thank to its plasticizer that swells the PHB amorphous phase. A promising solution to improve the mechanical properties of PHB seems to be the melt-processing of PHB with both plasticizer and EPDM. In fact, the plasticizer is more efficient than the elastomer in decreasing the PHB glass transition temperature and, because of the nucleating effect of EPDM, the decrease of the PHB modulus due to the plasticizer can be counterbalanced. © 2010 Society of Chemical Industry.

Published
2010

8. Crystalline microstructure and mechanical properties of crosslinked EPDM aged under gamma irradiation

Author

Planès, Emilie, Chazeau, Laurent, Chenal, J.-M., Vigier, Gérard, Stuhldreier, Thomas, Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and CPR Copola

Subjects
Ageing, Structure-properties relations, Crystallization, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience; The morphology and the mechanical properties at room temperature of crosslinked EPDM irradiated or not have been studied. It has been shown that these materials are composed of two phases: semlcrystalline zones with a crystalllnity ratio of 20% and mainly amorphous zones. The semicrystalline zones make a continuous path through the film and therefore control the mechanical properties of the material below the melting temperature. As irradiation (in the tested range of irradiation dose) and crosslinking degree have no significant influence on the arrangement and proportion of the crystalline lamellae, all samples have nearly the same mechanical behavior at small strains. At large strains, the interactions between amorphous and crystalline parts in semicrystalline zones play the main role in the mechanical response; irradiation, by degradation of these interactions, leads to a smaller hardening phenomenon and a decrease in elongation at break. From an application point of view, in spite of the low crystallinity fraction of these materials, the presence of an important number of crystallites, as evidenced by SAXS measurements, strongly limits the consequences of irradiation on the mechanical properties. However, the mechanical reinforcement strongly depending on the presence of these crystallites, It is therefore highly sensitive to temperature: this can be an important issue for the applications of these materials since their use temperature Is close to the crystallite melting temperature.

Published
2010

10. Dependence of the phase separation process on the reactive onset of network formation in simultaneous interpenetrating polymer

Author

Widmaier, J.M., Nilly, A., Chenal, J.-M., Mathis, A., Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Mateis, Laboratoire

Subjects
[SPI.MAT] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2005

11. Influence of the process on phase separation induced by radical copolymerization of styrene and divinylbenzene in the presence of reactive polyurethane network precursors

Author

Chenal, J.-M., Colombini, D., Widmaier, J.M., Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Mateis, Laboratoire

Subjects
[SPI.MAT] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2005

12. Entanglements in interpenetrating polymer networks evidenced by simple physico-chemical investigation

Author

Chenal, J.-M., Widmaier, J.M., Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Mateis, Laboratoire

Subjects
[SPI.MAT] Engineering Sciences [physics]/Materials, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2005

13. On the strain-induced fibrillar microstructure of polyethylene: Influence of chemical structure, initial morphology and draw temperature.

Author

Xiong, B., Lame, O., Chenal, J.-M., Rochas, C., and Seguela, R.

Subjects
CRYSTALLINITY, POLYETHYLENE, MICROFIBRILS, THERMAL properties
Abstract

The influence of crystalline microstructure and molecular topology on the strain-induced fibrillar transformation of semi-crystalline polyethylenes having various chemical structures including co-unit content and molecular weight and crystallized under various thermal treatments was studied by in situ SAXS at different draw temperatures. The long period of the nascent microfibrils, Lpf, proved to be strongly dependent on the draw temperature but non-sensitive to the initial crystallization conditions. Lpf was smaller than the initial long period. Both findings have been ascribed to the strain-induced melting-recrystallization process as generally claimed in the literature. The microfibrils diameter, Df, was shown to depend on the draw temperature and initial microstructure in a different way as Lpf. The evolution of Df was shown to correlate with the interfacial layer thickness that mainly depends on the chemical structure of the chains. It was concluded that, in contrast to Lpf, the microfibril diameter should not be directly sensitive to the strain-induced melting-recrystallization. The proposed scenario is that after the generation of the protofibrils by fragmentation of the crystalline lamellae at yielding, the diameter of the microfibril during the course of their stabilization should be governed by the chain-unfolding and subsequent aggregation of the unfolded chains onto the lateral surface of the microfibrils. The morphogenesis of the microfibrils should therefore essentially depend on the chemical structure of the polymer that governs its crystallization ability, its chain topology and subsequently its fragmentation process at yielding. This scenario is summed up in a sketch. [ABSTRACT FROM AUTHOR]

Published
2016
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14. Linear rheology of bis-urea functionalized supramolecular poly(butylacrylate)s: Part I – weak stickers.

Author

Callies, X., Fonteneau, C., Véchambre, C., Pensec, S., Chenal, J.-M., Chazeau, L., Bouteiller, L., Ducouret, G., and Creton, C.

Subjects
*UREA, *RHEOLOGY, *SUPRAMOLECULAR chemistry, *LINEAR systems, *QUADRUPLETS, *NEWTONIAN fluids
Abstract

We investigated the linear viscoelastic properties in the melt of a series of nearly monodisperse poly(n-butyl acrylate) (PnBA) chains center-functionalized with a bis-urea sticker group, able to self-associate by quadruple hydrogen bonding. All materials are viscoelastic liquids at 40 °C and their Newtonian viscosity varies from 100 to 5000 Pa s. However we show clearly that the viscosity changes non monotonously going through a minimum for a molecular weight (M n ) of 20 kg/mol and a sticker density of 1.1 wt%. We found two regimes: For M n < 20 kg/mol, the viscosity increases with decreasing M n , the linear viscoelastic properties change dramatically with temperature, forming a viscoelastic gel at 0 °C and flowing at 40 °C and the strength of the stickers association controls the size of molecular aggregates. However for M n > 20 kg/mol, the viscosity increases with M n , the rheology is controlled by the polymer dynamics and the stickers simply increase the terminal relaxation time relative to unfunctionalized PnBA of the same M n , as expected from sticky reptation theory. Despite clear evidence of sticker–sticker interactions by FTIR, none of the materials self-assemble at 20 °C into structures with a long range order detectable by SAXS. [ABSTRACT FROM AUTHOR]

Published
2015
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15. Electromechanical properties of ferroelectric polymers: Finsler geometry modeling and a Monte Carlo study.

Author

Egorov, V., Maksimova, O., Koibuchi, H., Bernard, C., Chenal, J.-M., Lame, O., Diguet, G., Sebald, G., Cavaille, J.-Y., and Takagi, T.

Subjects
*FERROELECTRIC polymers, *GEOMETRIC modeling, *GEOMETRIC approach, *MONTE Carlo method, *POLYVINYLIDENE fluoride, *DEFORMATIONS (Mechanics), *TETRAHEDRAL molecules
Abstract

• Electromechanical property of PVDF is studied by a new geometric modeling technique. • This technique is developed on the basis of Finsler geometry. • Finsler geometry is a mathematical framework for describing anisotropic phenomena. • Complex interactions of polarizations and polymers are implemented in metric function. • Reported experimental data are reproduced by MC with a single set of parameters. Polyvinylidene difluoride (PVDF) is a ferroelectric polymer characterized by negative strain along the direction of the applied electric field. However, the electromechanical response mechanism of PVDF remains unclear due to the complexity of the hierarchical structure across the length scales. In this letter, we employ the Finsler geometry model as a new solution to the aforementioned problem and demonstrate that the deformations observed through Monte Carlo simulations on 3D tetrahedral lattices are nearly identical to those of real PVDF. Specifically, the simulated mechanical deformation and polarization are similar to those observed experimentally. [ABSTRACT FROM AUTHOR]

Published
2021
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