Effective Interaction Parameter for Homologous Series of Deuterated Polystyrene-block-Poly(n-alkyl methacrylate) Copolymers
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- 作者：Du Yeol Ryu ; Changhak Shin ; Junhan Cho ; Dong Hyun Lee ; Jin Kon Kim ; Kristopher A. Lavery ; Thomas P. Russell
- 刊名：Macromolecules
- 出版年：2007
- 出版时间：October 16, 2007
- 年：2007
- 卷：40
- 期：21
- 页码：7644 - 7655
- 全文大小：342K
- 年卷期：v.40,no.21(October 16, 2007)
- ISSN：1520-5835
文摘
The effective interaction parameters, (F) of the homologous series of deuterated polystyrene-block-poly(n-alkyl methacrylate) copolymers (dPS-b-PAnMA) from methyl (n = 1) to hexyl (n = 6) side groupshave been investigated by small-angle neutron scattering and a Hartree (fluctuation correction) analysis. WhileF for dPS-b-PAnMA with n = 1 and 6 is a typical decreasing function of temperature, it is shown that F for nfrom 2 to 4 changes to a monotonic increase with temperature, revealing growing upward convexity. This actionculminates in a maximum of F for n = 5, which suggests an immiscibility loop-type behavior. Using the Hartreeanalysis for compressible diblock copolymers, the effect of directional interactions and the compressibility differencebetween the constituent blocks on F is discussed. The ordering transition temperatures, their pressure dependences,and F for the homologous block copolymer series are shown to be in good agreement with the experimentalvalues.