A noncubic triply periodic network morphology in poly(isoprene-b-styrene-b-ethylene oxide) triblock copolymers
A noncubic triply periodic network morphology in poly(isoprene-b-styrene-b-ethylene oxide) triblock copolymers
复制标题
DOI：
10.1021/ma011716x
复制
发表时间：
2002-08-27
期刊：
影响因子：
5.5
通讯作者：
Bates, FS
中科院分区：
文献类型：
--
作者：
Bailey, TS;Hardy, CM;Bates, FS
我们提供了线性聚（异戊二烯-b-苯乙烯-b-环氧乙烷）（PI-PS-PEO）三嵌段共聚物的表征数据，其中包含等体积分数的 PI 和 PS (f(PI) = f(PS)) 和不同量的 PEO，0 小于或等于 f(PEO) 小于或等于 (1)/(3)。通过 TEM、SAXS、动态机械光谱、静态双折射和 DSC 进行的详细表征表明了三种不同的形态：二域片层、三域非立方三周期网络结构和 PEO 含量增加的三域片层。这种相行为与之前报道的同源 PS-PI-PEO 三嵌段相图形成鲜明对比，后者在有限的两域和三域片层相之间包含四种不同的形态。初步分析表明，非立方网络结构包含三重配位的基本单元，但与之前在 PS-PI-PEO 中演示的立方核壳陀螺拓扑结构有根本不同。这个暂时指定的模型是陀螺仪和穿孔层状形态的结构混合体。这些结果提供了关于嵌段排序对 ABC 三嵌段共聚物在有序-无序转变附近的相行为的影响的定量证据。
We present characterization data for linear poly(isoprene-b-styrene-b-ethylene oxide) (PI-PS-PEO) triblock copolymers containing equal volume fractions of PI and PS (f(PI) = f(PS)) and varying amounts of PEO, 0 less than or equal to f(PEO) less than or equal to (1)/(3). Detailed characterization by TEM, SAXS, dynamic mechanical spectroscopy, static birefringence, and DSC indicates three distinct morphologies: two-domain lamellae, a three-domain noncubic triply periodic network structure, and three-domain lamellae with increasing PEO content. This phase behavior is in striking contrast with the homologous PS-PI-PEO triblock phase diagram, reported earlier, which contains four different morphologies between the limiting two- and three-domain lamellae phases. Preliminary analysis suggests the noncubic network structure contains elementary units of 3-fold coordination, yet fundamentally distinct from the cubic core-shell gyroid topology previously demonstrated in PS-PI-PEO. This tentatively assigned model is a structural hybrid of the gyroid and perforated lamellar morphologies. These results provide quantitative evidence regarding,the effects of block sequencing on the phase behavior of ABC triblock copolymers near the order-disorder transition.