Effect of interface on thermodynamic behavior of liquid crystalline type amphiphilic di-block copolymers
| Autor: | Jean-Pierre E. Grolier, Tomokazu Iyoda, Séverine A. E. Boyer, Hirohisa Yoshida |
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| Rok vydání: | 2007 |
| Předmět: |
chemistry.chemical_classification
Phase transition Materials science Azo compound Polymers and Plastics Small-angle X-ray scattering Thermodynamics Polymer Condensed Matter Physics chemistry.chemical_compound chemistry Clausius–Clapeyron relation Polymer chemistry Amphiphile Materials Chemistry Copolymer Side chain Physical and Theoretical Chemistry |
| Zdroj: | Journal of Polymer Science Part B: Polymer Physics. 45:1354-1364 |
| ISSN: | 1099-0488 0887-6266 |
| Popis: | In PEOm-b-PMA(Az)n amphiphilic diblock copolymers, nanoscale struc- tures exhibit an hexagonal-packed PEOm cylinders arrangement. To precisely investi- gate the role of interfacial interactions between hydrophilic PEOm and hydrophobic PMA(Az)n including mesogene sequences in the side chains, at the isotropic transi- tion, polymer systems are submitted to thermal and barometric effects under hydro- static pressure. The thermodynamic investigation is based on the original coupled calorimetric-PVT technique, yielding scanning transitiometry. Three phase diagrams can be represented versus pressure: (1) isotropic temperature described by Clapeyron equation (Tiso vs. P), (2) change of volume of the system (DViso vs. P), (3) entropy of the system (DSiso vs. P). In presence of mercury as pressure transmitting fluid, (dTiso/dP) as well as DViso and DSiso are larger for a PMA(Az)n homopolymer com- pared to those for the investigated copolymer. Additional calculations of DSiso using thermal and mechanical effects give consistent results. V C 2007 Wiley Periodicals, Inc. J |
| Databáze: | OpenAIRE |
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