【作者】 刘斌； 赵微微； 范雅珣； 王毅琳；

【Author】 Bin Liu;Weiwei Zhao;Yaxun Fan;Yilin Wang;CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry,Chinese Academy of Sciences;

【机构】 胶体界面与化学热力学中科院重点实验室中国科学院化学研究所；

【摘要】 寡聚表面活性剂已经体现出具有比传统单链表面活性剂和双子表面活性剂更低的临界聚集浓度,更高的表面活性,更丰富的聚集行为,因而具有更好的应用前景。然而,传统共价键型的寡聚表面活性剂合成复杂,分离纯化难,限制了寡聚表面活性剂的进一步发展和应用。虽然通过非共价相互作用构筑的寡聚表面活性剂大大简化了合成步骤,但是却存在着构筑的表面活性剂不稳定,可调控的区间小以及可构筑的寡聚表面活性剂的种类受限等问题。动态共价键具有和共价键相似的稳定性和强度,且具有可逆的形成和水解以及特异性识别的性质。因此,通过使简单基元连接上动态共价键的构筑单元,构筑基元之间的特异性识别作用将能够得到与共价型寡聚表面活性剂相当的稳定性,表面活性和聚集能力的更加丰富的寡聚表面活性剂,并大大简化寡聚表面活性剂的合成以及赋予其响应性。这里,我们通过简单合成的头基与不同疏水尾链通过动态亚胺键连接构筑得到一系列不同疏水链长的三聚季铵盐表面活性TDA-(Imine C7)3, TDA-(Imine C8)3, TDA-(Imine C10)3。我们通过核磁共振、表面张力、荧光发射光谱、动态光散射、浊度滴定等分别对这些表面活性剂进行了表征。结果显示,这一构筑方式大大降低了反应的位阻,使反应时间减少,反应产率增加。构筑得到的三聚季铵盐表面活性剂具有非常低的临界聚集浓度和平衡表面张力。因为动态亚胺键的引入,所有的表面活性剂显示了在碱性条件下形成,酸性条件下水解的性质。更多还原

【Abstract】 Oligomeric surfactants have shown lower critical aggregation concentration,higher surface activity and richer aggregation behavior than traditional single-chain surfactants and Gemini surfactants,and thus have better application prospects.Although oligomeric surfactants constructed by non-covalent interaction can greatly simplify the synthesis process,there are still some problems,such as instability of the constructed oligomeric surfactants,limited types of oligomeric surfactants.Dynamic covalent bond has similar stability and strength as covalent bond,and has the properties of reversible formation and dissociation as well as specific recognition.Therefore,by introducing building block of dynamic covalent bond to the simple primitives,with the specificity of recognition between primitive functional groups,it will be able to obtain abundant constructed oligomeric surfactants with considerable stability,surface activity and aggregation ability to covalent oligomeric surfactant,and with greatly simplified synthesis process and responsiveness.Here,we design and synthesize a series of oligomeric quaternary ammonium surfactants with different hydrophobic chain lengths TDA-（Imine C7）₃,TDA-（Imine C8）₃,and TDA-（Imine C10）₃ through dynamic imine bond connection between a simple synthetic head group and different hydrophobic tail chains.We characterize these surfactants by NMR,surface tension,fluorescence emission spectra,dynamic light scattering and turbidity titration.Results show that the dynamic covalent bonded strategy for construct oligomeric surfactant can greatly reduce the steric hindrance,and thus reduce the reaction time and enhance the reaction yield.The constructed quaternary ammonium surfactants all have very low critical micelle concentration and low equilibrium surface tension.Because of the introduction of dynamic imine bonds,all surfactants exhibit the properties of forming under alkaline conditions and hydrolyzing under acidic conditions.更多还原