دورية أكاديمية
Phase behaviour, micellar structure and linear rheology of tetrablock copolymer Tetronic 908
| العنوان: | Phase behaviour, micellar structure and linear rheology of tetrablock copolymer Tetronic 908 |
|---|---|
| المؤلفون: | Puig-Rigall, Joan, Obregon-Gomez, Ines, Monreal-Pérez, Pablo, Radulescu, Aurel, Blanco-Prieto, María J., Dreiss, Cécile A., González-Gaitano, Gustavo |
| المصدر: | Journal of colloid and interface science 524, 42 - 51 (2018). doi:10.1016/j.jcis.2018.03.096 |
| بيانات النشر: | Elsevier |
| سنة النشر: | 2018 |
| المجموعة: | Forschungszentrum Jülich: JuSER (Juelich Shared Electronic Resources) |
| مصطلحات موضوعية: | info:eu-repo/classification/ddc/540 |
| جغرافية الموضوع: | DE |
| الوصف: | Tetronics are X-shaped block-copolymers of polyethylene oxide and polypropylene oxide, which self-assemble into micelles and can undergo a sol-gel transition; these transitions are dependent on temperature, concentration but also pH, due to the central diamine group of the tetrablock. We report the nanoscale morphologies underlying these different phases and the rheology of the systems for a very large, highly hydrophilic block copolymer, Tetronic 908, through the combined use of oscillatory rheology, steadyblock-state and time-resolved fluorescence, small-angle neutron scattering (SANS), dynamic light scattering (DLS) and Fourier transform infrared attenuated total reflectance (FTIR-ATR). At low concentrations, SANS reveal core-shell micelles of ca. 10 nm radius, presenting a dehydrated core and a highly hydrated shell, with relatively small aggregation numbers (Nagg ≈ 13). The micelles are notably affected by the pH, due to the protonation of the central amine spacer at low pH (pH ≈ 2), which shifts micellization to higher temperature, with smaller micelles than at natural pH. In the intermediate concentration regime (10–15%), micelles become smaller (Nagg ≈ 5), and present a higher hydration of the core. In the high concentration regime, Tetronic 908 undergoes a sol-gel transition above a threshold temperature, which is fully inhibited at acidic pH. SANS data from the gel phase reveal a BCC order of tightly packed spheres. Temperature sweeps in oscillatory rheology show a shift of the onset of gelation towards lower temperatures as concentration increases, an increase in the elastic modulus G′ and an expansion of gel region over a larger range of temperatures. SANS and rheology reveal that at pH below the natural pH (ca. 8), gelation is shifted to higher temperatures, but the morphology of the gels is similar, while under highly acidic conditions the gelation is fully suppresed. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| العلاقة: | info:eu-repo/semantics/altIdentifier/issn/0021-9797; info:eu-repo/semantics/altIdentifier/wos/WOS:000434494400006; info:eu-repo/semantics/altIdentifier/issn/1095-7103; info:eu-repo/semantics/altIdentifier/pmid/pmid:29631218; https://juser.fz-juelich.de/record/844926Test; https://juser.fz-juelich.de/search?p=id:%22FZJ-2018-02268%22Test |
| الإتاحة: | https://doi.org/10.1016/j.jcis.2018.03.096Test https://juser.fz-juelich.de/record/844926Test https://juser.fz-juelich.de/search?p=id:%22FZJ-2018-02268%22Test |
| حقوق: | info:eu-repo/semantics/closedAccess |
| رقم الانضمام: | edsbas.FBD68027 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |