Effect of interface on thermodynamic behavior of liquid crystalline type amphiphilic di‐block copolymers

Boyer, Séverine A.E.; Grolier, J.-P.E.; Yoshida, Hiroyuki; Iyoda, Tomokazu

doi:10.1002/polb.21134

Cited by 15 publications

(12 citation statements)

References 37 publications

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“…During annealing at reasonably lower temperature than the glass transition temperature (T g ), the system tends to evolve towards lower energetic states and to get closer to a virtual equilibrium state. 6,11,12 The pressure sensitivity was illustrated in situ during polymer phase transitions 13,14 and ex-situ on solid polymer. In this latter case, an increase of the glass transition temperature, as well as an endothermic peak located nearby T g , can be observed after annealing.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Dasriaux

Castagnet

Thilly

et al. 2013

J of Applied Polymer Sci

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The constrained fraction of the amorphous phase of semi-crystalline polymers is in an out-of-equilibrium state so that "physical aging"-like features can be observed (e.g., by calorimetry) even above the glass transition temperature. This was already addressed in the literature in several semi-crystalline polymers at atmospheric pressure. Despite the well-known influence of pressure on molecular mobility, the pressure-sensitivity of these microstructure rearrangements has never been tackled. This study focuses on annealing in highly pressurized Poly-Ether-Ether-Ketone (PEEK), compared with atmospheric pressure. The phenomenon is tracked by ex-situ Differential Scanning Calorimetry (DSC). A significant influence of pressure is evidenced, without any complete equivalence with temperature. Indeed, pressure seems to confine rearrangements within spatially limited domains. The stability and coexistence of reorganization processes upon successive annealings is also investigated. Finally, relationships between constrained and free amorphous phase rearrangements are discussed via the different glass transition shifts observed after atmospheric or high pressure annealing.

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Section: Introductionmentioning

confidence: 99%

Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Dasriaux

Castagnet

Thilly

et al. 2013

J of Applied Polymer Sci

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“…In complete contrast, ΔS tr increases when the pressure is exerted by N 2 and CO 2 . In this respect, as observed above, N 2 is a "neutral" fluid as compared to "chemically active" CO 2 , and consequently the large increase of ΔS tr shows that the organization of nanostructures is the easiest the more "active" is the fluid, in particular when the fluid is in supercritical state [32][33][34]. The influence of the pressure-transmitting fluid on the transition entropy at the interface is well illustrated by the increase of the Clapeyron slope (dT/dp) tr in the sequence Hg < N 2 < CO 2 as shown Fig.…”

Section: Role Of High-pressure Gas On Molecular Self-assembled Organimentioning

confidence: 57%

Modification of molecular organization of polymers by gas sorption: Thermodynamic aspects and industrial applications

Boyer

Yamada

Yoshida

et al. 2009

Pure and Applied Chemistry

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13th International Symposium on Solubility Phenomena and Related Equilibrium Processes (ISSP-13), Dublin, Ireland, 27–31 July 2008International audienceIn polymer science, gas–polymer interactions play a central role for the development of new polymeric structures for specific applications. This is typically the case for polymer foaming and for self-assembling of nanoscale structures where the nature of the gas and the thermodynamic conditions are essential to control. An important applied field where gas sorption in polymers has to be documented through intensive investigations concerns the (non)-controlled solubilization of light gases in the polymers serving, for example, in the oil industry for the transport of petroleum fluids. An experimental set-up coupling a vibrating-wire (VW) detector and a pVT technique has been used to simultaneously evaluate the amount of gas entering a polymer under controlled temperature and pressure and the concomitant swelling of the polymer. Scanning transitiometry has been used to determine the interaction energy during gas sorption in different polymers; the technique was also used to determine the thermophysical properties of polymers submitted to gas sorption. The role of the pressurizing fluid has been documented in terms of the influence of pressure, temperature, and nature of the fluid

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“…Regarding nanoscale self-assembled molecular organization in liquid crystallinetype amphiphilic diblock copolymers, the use of T CST is well described [6,10,11] by the systematic investigation of PEO m -b-PMA(Az) n type polymers (with m and n degrees of polymerization) containing hydrophilic polyethylene oxide (PEO) and hydrophobic azophenyl (PMA(Az)) moieties. Isobaric scans over the isotropic transition of PEO 114 -b-PMA(Az) 20 using either mercury or supercritical CO 2 as pressurizing fluids demonstrated that "inert" mercury and "chemically active" CO 2 have quite opposite effects on the Clapeyron slope of this transition.…”

Section: Figmentioning

confidence: 99%

Polymer Microstructures: Modification and Characterization by Fluid Sorption

Boyer

Baba

Nédélec³

et al. 2008

Int J Thermophys

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Polymer micro-organization can be modified by a combination of three constraints, thermal, hydrostatic, and fluid sorption. In selecting the fluid's nature, chemically active or inert, and its physical state, liquid or supercritical, new "materials" can be generated. In addition, the interplay of temperature and pressure allows tailoring the obtained material structure for specific applications. Several complementary techniques have been developed to modify, analyze, and characterize the end products: scanning transitiometry, vibrating-wire (VW)-PVT coupling, thermoporosimetry, and temperature-modulated DSC (TMDSC). The great variety of possible applications in materials science is illustrated with different polymers which can produce materials from soft gel to rigid foams when submitted to fluid sorption, typical fluids being methane or a simple gas (CO 2 or N 2 ). Absorption of an appropriate fluid in a crosslinked polymer leads to a swelling phenomenon. Thermoporosimetry is a calorimetric technique developed to measure the shift by confinement of thermal-transition temperatures of the swelling fluids, which can be currently used solvents or mercury.Application of thermoporosimetry to a swollen cross-linked polymer allows calculation of the mesh size distribution and evaluation of the degree of reticulation of the polymer. The same technique can be applied to characterize the pore size distribution in a foamed polymer.

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Effect of interface on thermodynamic behavior of liquid crystalline type amphiphilic di‐block copolymers

Cited by 15 publications

References 37 publications

Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Modification of molecular organization of polymers by gas sorption: Thermodynamic aspects and industrial applications

Polymer Microstructures: Modification and Characterization by Fluid Sorption

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