Synthesis and self-assembly of a linear coil-coil-rod ABC triblock copolymer
Synthesis and self-assembly of a linear coil-coil-rod ABC triblock copolymer
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DOI：
10.1007/s10118-014-1533-7
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发表时间：
2014-09
影响因子：
4.3
通讯作者：
Lingying Shi;Yu Pan;Qi-Kai Zhang;Yu Zhou;Xinghe Fan;Zhihao Shen
中科院分区：
文献类型：
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作者：
Lingying Shi;Yu Pan;Qi-Kai Zhang;Yu Zhou;Xinghe Fan;Zhihao Shen
在一种新的线性螺旋-螺旋-棒ABC三嵌段共聚物（triBCP）中观察到两种不同复杂纳米结构之间有趣的有序-有序转变。首先，通过原子转移自由基聚合法合成了聚二甲基硅氧烷-b聚苯乙烯-b聚{2，5-二[（4-甲氧基苯基）氧羰基]苯乙烯}（PDMS-b-PS-b-PMPCS）三元嵌段共聚物（ABC triBCP）。PDMS、PS和PMPCS嵌段的聚合度分别为58、159和106，并且PDMS、PS和PMPCS的相应体积分数分别为0.09、0.29和0.62。通过小角X射线散射、一维广角X射线散射和透射电子显微镜实验研究了PDMS-b-PS两嵌段共聚物前体和最终三嵌段共聚物的相行为。PDMS-b-PS前体在热退火后自组装成具有相对小的周期尺寸的六方填充圆柱体。当三嵌段共聚物在PMPCS嵌段处于无定形状态的相对低的温度（120 °C）下退火时，triBCP形成具有相对大的周期性尺寸的核-壳六方填充圆柱体（CSH）。在triBCP在PMPCS嵌段转变为液晶（LC）相的140 °C以上退火之后，纳米相分离的结构转变为三相四层层状结构（LAM-3 P4 L）。因此，伴随着PMPCS嵌段从非晶态到LC相的转变，在PDMS-b-PS-b-PMPCS ABC triBCP中发生了从CSH到LAM-3 P4 L的有序-有序转变。
An interesting order-order transition between two different complex nanostructures was observed in a new liquid crystalline linear coil-coil-rod ABC triblock copolymer (triBCP). First, the ABC triBCP, poly(dimethylsiloxane)-bpolystyrene-b-poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PDMS-b-PS-b-PMPCS), was synthesized through sequential atom transfer radical polymerization. The degrees of polymerization of PDMS, PS, and PMPCS blocks are 58, 159, and 106, and the corresponding volume fractions of PDMS, PS, and PMPCS are 0.09, 0.29, and 0.62, respectively. The phase behaviors of the PDMS-b-PS diblock copolymer precursor and the final triblock copolymer were studied by smallangle X-ray scattering, one-dimensional wide-angle X-ray scattering, and transmission electron microscopy experiments. The PDMS-b-PS precursor self-assembles into hexagonally packed cylinders with a relatively small periodic size after thermal annealing. When the triblock copolymer is annealed at a relatively low temperature (120 °C) at which the PMPCS block is in the amorphous state, the triBCP forms core-shell hexagonally packed cylinders (CSH) with a relativly large periodic size. After the triBCP is annealed above 140 °C at which the PMPCS block transforms to the liquid crystalline (LC) phase, the nanophase-separated structure transforms to a three-phase four-layer lamellar structure (LAM-3P4L). Thus, accompanied with the transition of the PMPCS blocks from the amorphous state to the LC phase, the order-order transition from CSH to LAM-3P4L occurs in the PDMS-b-PS-b-PMPCS ABC triBCP.