作者:Young-Ki Kim、Krishna R. Raghupathi、Joel S. Pendery、Piyachai Khomein、Uma Sridhar、Juan J. de Pablo、S. Thayumanavan、Nicholas L. Abbott
DOI:10.1021/acs.langmuir.8b01944
日期:2018.8.28
energy and not change in the easy axis of the LC. In contrast, the rate of the phase transition induced by absorption of oligomers into the LC decreased from monomer to trimer, suggesting that constraints on configurational degrees of freedom influence the absorption free energies of the oligomers. Interestingly, the oligomer-induced transition from the nematic to isotropic phase of 5CB was observed to
我们报告了两亲低聚物的水溶液对热致液晶(LCs)的微米厚膜的有序化的影响的调查,从而解决了以前对单体和聚合物两亲与LCs相互作用的研究所产生的知识空白。具体来说,我们合成了单体,二聚体和三聚体形式的两亲性低聚物(具有癸基疏水性和五乙二醇亲水性结构域),并将该低聚物的水溶液与4'-戊基-4-联苯甲腈(5CB)的向列膜温育。所有两亲性低聚物都导致顺序地进行表面驱动的取向(平面至垂直),然后发生本体相转变(向列至各向同性),其动力学很大程度上取决于低聚度。定向转变的动力学从单体加速到三聚体,这与吸附自由能增加的影响一致。然而,定向过渡的机制涉及锚固能量的减少,而LC的易轴却没有变化。相反,由低聚物吸收到LC中引起的相变速率从单体到三聚体降低,这表明对构型自由度的限制会影响低聚物的吸收自由能。有趣的是,观察到低聚物诱导的5CB向列相向各向同性相的转变在水–5CB界面成核,这与上述由低聚物引起的锚定