کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5184912 1381061 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dilute solutions and phase behavior of polydisperse A-b-(A-co-B) diblock copolymers
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Dilute solutions and phase behavior of polydisperse A-b-(A-co-B) diblock copolymers
چکیده انگلیسی

The effect of polydispersity on dilute solution properties and microphase separation of polydisperse high-molecular-weight (Mw > 105 g mol−1) polystyrene-block-poly(styrene-co-acrylonitrile) diblock copolymers, PS-block-P(S-co-AN), was studied in this work. For experiments, a series of diblock copolymers with variable weight fractions of acrylonitrile units (wAN = 0.08-0.29) and length of block P(S-co-AN) was synthesized using nitroxide-mediated radical polymerization (NMP) technique, namely, by chain extension of nitroxide-terminated polystyrene (PS-TEMPO). According to light scattering and viscometry measurements in dilute tetrahydrofuran (THF) solutions the studied diblock copolymers assumed random coil conformation with the values of characteristic structure factor Rg/Rh = 1.50-1.76. It was found that polydisperse diblock copolymers being in strong segregation limit (SSL) self-assembled into microphase-separated ordered morphologies at ordinary temperature. The long periods of lamellar microdomains were larger compared to theoretical predictions for hypothetical monodisperse diblock copolymers. It was demonstrated by means of SAXS and TEM that a transition from a lamellar (LAM) to irregular face-centered-cubic (FCC) morphology occurred with increasing volume fraction of P(S-co-AN) block.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 50, Issue 11, 22 May 2009, Pages 2451-2459
نویسندگان
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