A2-star-(B-alt-C)共聚合物在熔融態和溶液態中階級性結構內有結構相行為的探討

Abstract

我們運用秏散粒子動力學模擬A2-star-(B-alt-C)共聚合物於熔融態和溶液態中的等級結構相行為。於熔融態中，藉由改變整體聚合度、每一交替塊狀聚合度與組成，我們成功的觀察到各聚合度下，隨著A組成的增加，其型態變化為：小尺寸BC交替層狀平行於A塊狀和BC交替塊狀形成的大尺寸層狀內(LB,C-within-LA,BC)→小尺寸BC交替層狀形成六方堆積同軸包覆柱狀於A-matrix中(Coaxial LB,C-within- )→小尺寸BC交替層狀形成包覆同心球於A-matrix中(Co-centric LB,C-within-SBC)；在相同組成下，隨著聚合度的增加，微結構型態並未改變，但可以觀察到小尺寸層狀數目亦隨之增加。値得注意的是，小尺寸層狀厚度並非完全相同，進ㄧ步由觀察LB,C-within-LA,BC其鏈摺疊排列方式得知小尺寸層度厚度的變化原因。於溶液態中，使用一對A有選擇性的溶劑、喜歡A討厭B與C，來觀察是否選擇性溶劑的添加能產生和熔融態中隨A組成增加，產生相同一系列的微結構型態衍變，我們觀察到的型態有：小尺寸BC交替層狀平行於A塊狀和BC交替塊狀形成的大尺寸層狀內(LB,C-within-LA,BC)、小尺寸BC交替層狀形成同軸包覆柱狀於A塊狀包覆於最外圍的柱狀微胞(Coaxial LB,C-within-CBC micelles)、小尺寸BC交替層狀形成包覆同心球於A塊狀包覆於最外圍的球型微胞(Co-centric LB,C-within-SBC micelles)、小尺寸BC交替層狀於A塊狀包覆於最外圍的球型微胞(Segmented worm-like micelles)和柱狀微包與球型微包或不同型態球型微包共存的現象。在溶液態中隨著選擇性溶劑的添加較熔融態中隨著組成的增加觀察到許多不一樣的微結構衍變，其中有趣的是觀察到球型微包型態的改變，由Co-centric LB,C-within-SBC micelles至Segmented worm-like micelles的衍變：當整體聚合度N增加、高分子體積分率

We employ the dissipative particle dynamics (DPD) to examine the self-assembly behavior of A2-star-(B-alt-C) molecules in the melt and solution regimes. In the melt, we successfully observe various types of hierachical structure-within-structures, such as B and C alternating layers in parallel-within-lamellae, coaxial B and C alternating domains within hexagonally packed BC-formed cylinders in the A-matrix, and co-centric BC-alternating domains within BC-formed spheres in the A-matrix, by increasing the A composition. We can find that when the copolymer chain length increases, though the hierachical structure type is maintained, the number of small-length-scale lamellae that can form within the large-length-scale structure increases and thickness of small-length-scale lamellae are not all the same. In the solution , various types of hierachical structure-within-structures, such as B and C alternating layers in parallel-within-lamellae, coaxial B and C alternating domains cladding with A within BC-formed cylindrical micelles, coexistent with coaxial B and C alternating domains cladding with A within BC-formed cylindrical micelles and co-centric BC-alternating domains cladding with A within BC-formed spherical micelles, co-centric BC-alternating domains cladding with A within BC-formed spherical micelles, coexistent with co-centric BC-alternating domains cladding with A within BC-formed spherical micelles and segmented worm-like micelles, segmented worm-like micelles are observed when an A-selective solvent is added. There are more variation of the self-assembly behavior in the solution regime than in the melt regime. The specially interesting is the sphere micelles variation from co-centric BC-alternating domains cladding with A within BC-formed spherical micelles to segmented worm-like micelles when totally polymerization increasing, alternating blocks polymerization increasing, A composition decreased and copolymers volume fraction decreased that we call them N effect, q effect, fA effect and