Influence of linear and branched perfluoroalkylated side chains on the π–π stacking behaviour of hexa-peri-hexabenzocoronene and thermotropic properties
Influence of linear and branched perfluoroalkylated side chains on the π–π stacking behaviour of hexa-peri-hexabenzocoronene and thermotropic properties
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DOI：
10.1080/10610278.2013.831860
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发表时间：
2014-02
影响因子：
3.3
通讯作者：
Bassam Alameddine;Olivier F. Aebischer;B. Heinrich;D. Guillon;B. Donnio;T. Jenny
中科院分区：
文献类型：
--
作者：
Bassam Alameddine;Olivier F. Aebischer;B. Heinrich;D. Guillon;B. Donnio;T. Jenny
研究了两种不同系列的带有直链或支链全氟烷基化侧链的六-近-六苯并酮（HBC）的热致性质和自组装，每种都具有广泛的烷基间隔基和全氟尾长度。热重分析、差示扫描量热法、偏振光学显微镜和小角 X 射线散射实验之间的相关性表明，正如预期的那样，转变温度和相稳定性受到脂肪族间隔基长度和奇/偶性质以及全氟化部分的尺寸和结构（线性与分叉）的决定作用的影响。大多数研究的HBC衍生物都显示出单柱六角形柱状相，其中柱是通过一方面HBC芳香核和脂肪族间隔基之间以及另一方面脂肪族间隔基和氟化尾部之间的双重偏析过程而构造的。对于具有长线性间隔基的衍生物，未倾斜或准未倾斜的 HBC 堆叠的核心被与氟化外围隔离的圆柱形脂肪族包络包围，而对于具有较短线性间隔基的衍生物，保持相同的结构，除了脂肪族包络偏离圆柱形并导致系列第一项的矩形包络对称破缺。在具有支化间隔的四种 HBC 中，两种是非晶态的，而其他两种衍生物则保持柱状相，但具有倾斜的 HBC 堆叠。因此，该系列中多态性的演变可能与两个界面面积的变化相关。
The thermotropic properties and self-assembly of two different series of hexa-peri-hexabenzocoronenes (HBC) bearing either linear or branched perfluoroalkylated side chains, each with a wide range of alkyl spacer and perfluorinated tail lengths, have been studied. Correlations between thermogravimetric analysis, differential scanning calorimetry, polarised optical microscopy and small-angle X-ray scattering experiments revealed, as expected, that the transition temperatures and phase stability are influenced by the determining roles of the aliphatic spacer length and odd/even nature, as well as the size and structure (linear vs. bifurcation) of the perfluorinated sections. Most of the investigated HBC derivatives showed a single-column hexagonal columnar phase, where the columns are structured by a double segregation process between HBC aromatic cores and aliphatic spacers, on the one hand, and between aliphatic spacers and fluorinated tails, on the other hand. For the derivatives with long linear spacers, cores of untilted or quasi-untilted HBC stacks are surrounded by a cylindrical aliphatic envelope segregated from the fluorinated periphery, whereas for those with shorter linear spacers, the same structure is kept, except that the aliphatic envelope deviates from cylindricality and causes a symmetry break to rectangular envelope for the first term of the series. Of the four HBC with branched spacers, two are amorphous, whereas a columnar phase is maintained for the other two derivatives, but with tilted HBC stacks. Consequently, the evolution of the polymorphism in the series could be correlated with the variation of both interface areas.