کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184310 1381044 2011 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Generality of anomalous expansion of polymer chains in supercritical fluids
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Generality of anomalous expansion of polymer chains in supercritical fluids
چکیده انگلیسی

By using in-situ neutron reflectivity, we have investigated swelling isotherms of solvophilic and solvophobic end-grafted/non-grafted polymer chains on solid substrates in supercritical carbon dioxide and supercritical ethane. It was found that anomalous expansion of the polymer chains associated with excess absorption of the fluid molecules occurs in the large compressible regions of both supercritical fluids (SCFs) regardless of the polymer-fluid interactions. In addition, we found that the excess expansion of the solvophobic polymer chains in both SCFs collapse onto one master curve under the same magnitude of density fluctuations in the fluids. A simple thermodynamic two-state model along with the experimental results proposes that polymer chains are expanded independently of the polymer-fluid interactions to further change solvent density fluctuations around the polymer chains, thereby lowering the free energy of the polymer/SCF systems.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 52, Issue 19, 1 September 2011, Pages 4331-4336
نویسندگان
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