Knaapila M, Bright D W, Stepanyan R, Torkkeli M, Almásy L, Schweins R, Vainio U, Preis E, Galbrecht F, Scherf U, Monkman A P
Physics Department, Institute for Energy Technology, Kjeller, Norway.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 May;83(5 Pt 1):051803. doi: 10.1103/PhysRevE.83.051803. Epub 2011 May 19.
The formation of self-organized structures in poly(9,9-di-n-alkylfluorene)s ∼1 vol % methylcyclohexane (MCH) and deuterated MCH (MCH-d(14)) solutions was studied at room temperature using neutron and x-ray scattering (with the overall q range of 0.00058-4.29 Å(-1)) and optical spectroscopy. The number of side chain carbons (N) ranged from 6 to 10. The phase behavior was rationalized in terms of polymer overlap, cross-link density, and blending rules. For N=6-9, the system contains isotropic areas and lyotropic areas where sheetlike assemblies (lateral size of >400 Å) and free polymer chains form ribbonlike agglomerates (characteristic dimension of >1500 Å) leading to a gel-like appearance of the solutions. The ribbons are largely packed together with surface fractal characteristics for N=6-7 but become open networklike structures with mass fractal characteristics for N=8-9, until the system goes through a transition to an isotropic phase of overlapping rodlike polymers for N=10. The polymer order within sheets varies allowing classification for loose membranes and ordered sheets, including the so-called β phase. The polymers within the ordered sheets have restricted motion for N=6-7 but more freedom to vibrate for N=8-9. The nodes in the ribbon network are suggested to contain ordered sheets cross-linking the ribbons together, while the nodes in the isotropic phase appear as weak density fluctuations cross-linking individual chains together. The tendencies for macrophase separation and the formation of non beta sheets decrease while the proportion of free chains increases with increasing N. The fraction of β phase varies nonlinearly, reaching its maximum at N = 8.
在室温下，使用中子散射和X射线散射（总q范围为0.00058 - 4.29 Å⁻¹）以及光谱学研究了聚（9,9 - 二 - n - 烷基芴）在约1体积%的甲基环己烷（MCH）和氘代MCH（MCH - d₁₄）溶液中自组织结构的形成。侧链碳原子数（N）范围为6至10。根据聚合物重叠、交联密度和混合规则对相行为进行了合理化解释。对于N = 6 - 9，该体系包含各向同性区域和溶致区域，其中片状聚集体（横向尺寸>400 Å）和游离聚合物链形成带状团聚物（特征尺寸>1500 Å），导致溶液呈现凝胶状外观。对于N = 6 - 7，这些带在很大程度上堆积在一起，具有表面分形特征，但对于N = 8 - 9则变成具有质量分形特征的开放网络状结构，直到该体系经历转变，对于N = 10时变为重叠棒状聚合物的各向同性相。片层内的聚合物有序性各不相同，可分为松散膜和有序片层，包括所谓的β相。对于N = 6 - 7，有序片层内的聚合物运动受限，但对于N = 8 - 9则有更多的振动自由度。带状网络中的节点被认为包含将带交联在一起的有序片层，而各向同性相中的节点则表现为将单个链交联在一起的弱密度涨落。随着N的增加，宏观相分离和非β片层形成的趋势降低，而游离链的比例增加。β相的比例呈非线性变化，在N = 8时达到最大值。
