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State of gelation of fully conjugated conducting gels. Gel fraction, swelling, and nuclear magnetic relaxation
被引:33
|作者:
Viallat, A
[1
]
PepinDonat, B
[1
]
机构:
[1] CEN GRENOBLE, CEA, DEPT RECH FONDAMENTALE MAT CONDENSEE, LAB PHYS METAUX ORGAN S13M, F-38054 GRENOBLE 9, FRANCE
关键词:
D O I:
10.1021/ma961909y
中图分类号:
O63 [高分子化学(高聚物)];
学科分类号:
070305 ;
080501 ;
081704 ;
摘要:
Statistical properties of well-defined fully conjugated poly(3-octylthiophene) (POT) gels are explored above glass transition and fusion temperatures by varying the cross-link functionality, f, and the cross-link concentration, R-i. Four series of gels are prepared using four different cross-linking agents. The state of gel connectivity, characterized by the gel fraction is found to depend on the distance to the gelation threshold, epsilon, expressed within a mean-field percolation approach. In the range of explored crosslink densities, H-1 NMR and swelling experiments reveal that the active structural strands of both dry and swollen gels are the linear chain segments defined by adjacent cross-links. These segments are disengaged from one another in swollen gels. The two variables, chain segment contour length and epsilon, are functions of the product fR(i). This parameter is the relevant variable for the description of POT gel structures: master curves of the quantities gel fraction, swelling ratio, and H-1 transverse relaxation rate are obtained versus fR(i).
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页码:4679 / 4687
页数:9
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