کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5190760 | 1381216 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Cocrystallization mechanism of poly(3-alkyl thiophenes) with different alkyl chain length
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Cocrystallization mechanism of poly(3-alkyl thiophenes) with different alkyl chain length Cocrystallization mechanism of poly(3-alkyl thiophenes) with different alkyl chain length](/preview/png/5190760.png)
چکیده انگلیسی
The crystallization rates of poly(3-alkyl thiophene) (P3AT) cocrystals having different alkyl chain length (e.g. hexyl and octyl) of the components are measured using differential scanning calorimetry (DSC) technique. Two pairs of cocrystals with varying compositions of the components viz. poly(3-octyl thiophene) (P3OT(R), regioregularity 89Â mol%) and poly(3-hexyl thiophene) [P3HT(R), regioregularity 92Â mol% and P3HT-2 regioregularity 82Â mol%] are used. In both the systems the isothermal temperature range (TR) in the same time scale of crystallization is found to decrease with increasing alkyl chain length in the blends. The crystallization rate at the same Tc decreases with increasing alkyl chain length P3AT concentration and the Avrami exponent values of cocrystals are same with those of the component values. The low Avrami exponent values (0.23-1.16) in all the samples suggest the presence of rigid amorphous portion which can not diffuse out quickly from the crystal growth front (soft impingement). Analysis of crystallization rate using Laurintzen-Hoffman (L-H) growth rate theory indicates that there is regime-I to regime-II transition in all the samples. The product of lateral (Ï) and end surface energy (Ïe) values are found to decrease with increasing the concentration of longer alkyl chain P3AT in the blend. Analysis of Ï values according to a theory of Hoffman et al. [Hoffman JD, Miller RL, Marand H, Rotiman DR. Macromolecules 1992;25:2221. [14]] indicates that there is chain extension of the components in the melt of the blends, however, the entropy of cocrystallization has different sign to the two systems. Cocrystallization in P3HT(R)/P3OT(R) system is an entropy driven process but that in P3HT(2)/P3OT(R) system is entropy forbidden process. A possible explanation of cocrystallization in the later system has been attributed from small interaction between the components.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 19, 8 September 2005, Pages 8321-8330
Journal: Polymer - Volume 46, Issue 19, 8 September 2005, Pages 8321-8330
نویسندگان
Susmita Pal, Arun K. Nandi,