Hierarchical Structures in Thin Films of Miktoarm Star Polymers: Poly(n-hexyl isocyanate)(12K)鈥揚oly(蔚-caprolactone)1鈥?(5K)
详细信息 查看全文
- 作者：Young Yong Kim ; Sungmin Jung ; Changsub Kim ; Brian J. Ree ; Daisuke Kawato ; Naoki Nishikawa ; Daichi Suemasa ; Takuya Isono ; Toyoji Kakuchi ; Toshifumi Satoh ; Moonhor Ree
- 刊名：Macromolecules
- 出版年：2014
- 出版时间：November 11, 2014
- 年：2014
- 卷：47
- 期：21
- 页码：7510-7524
- 全文大小：735K
- ISSN：1520-5835
文摘
A series of miktoarm star polymers, [poly(n-hexyl isocyanate)(12K)]鈥揫poly(蔚-caprolactone)1鈥?(5K)] (PHIC鈥揚CL1鈥?) (composed of a rigid self-assembling PHIC arm and one to three flexible crystallizable PCL arms), were investigated to examine the polymers鈥?thermal properties and nanoscale thin film morphologies. The miktoarm polymers were stable up to 180 掳C. The PHIC and PCL arm components underwent phase separation during the solution casting, drying, and post toluene-annealing processes, forming interesting but very complex thin film morphologies. The resulting thin film morphologies were examined in detail for the first time using synchrotron grazing incidence X-ray scattering (GIXS) measurements and quantitative data analysis. All of the miktoarm star polymer films formed vertically well-oriented lamellar structures, regardless of the number and length of PCL arms. These structures were quite different from the cylindrical structures commonly observed in conventional flexible diblock copolymer films having comparable volume fractions. The individual PHIC and PCL lamellar domains self-assembled to form their own respective morphological structures. The PHIC lamellae consisted of a mixture of horizontal and vertical multibilayer structure domains, as observed in the PHIC homopolymer film. The PCL lamellae formed fringed micelle-like crystals and/or highly imperfect folded crystals that differed significantly from the structures found in a PCL homopolymer film composed of typical folded lamellar crystals. These PCL crystals were formed with a mixture of vertical and horizontal orthorhombic lattices. Overall, the GIXS analysis revealed that the parameters that characterized the hierarchical structures in the thin films depended significantly on the number and length of the PCL arm and its crystallization characteristics as well as the chain rigidity and multibilayer structure formation characteristics of the PHIC arm.