Mechanism Investigations Of Supra-Amphiphilies In Smart Motions Based On Marangoni Effect

The research of Marangoni motion in the field of self-driving is of great significance.Among them,self-driving devices represented by "soap-boats" have been widely studied.This type of device is used to release surfactants on the surface,resulting in a surface tension gradient,triggering the Marangoni flow,and promoting device moving.This feature is favored due to its fast response and strong acting force.However,when the surfactants are released,they will be rapidly adsorbed and saturate on the surface,causing the gradient disappear,and lead to the movement to stagnate for a short time.This bottleneck causes the research in this field to face severe challenges.In order to solve the above problems,this paper introduces the concept of supra-amphiphilic molecules into the smart motion based on the Marangoni effect,and uses its noncovalent bond feature to control the adsorption form of surfactants at the interface so as to eliminate excesses aggregation in the interface,which to realize the purpose of maintaining surface tension gradients.For this reason,the dissertation first used the supramolecular interaction between the host molecule and the surfactant of the solution system to form a soluble supramolecular complex,and dissolved the surfactant from the adsorption layer on the solution surface to the bulk phase.To this end,we designed a "soap boat" experiment to achieve long-term "soap boat" movement by regulating the concentration of cyclodextrin molecules in solution.Further,based on the pH-responsiveness of the carboxyl surface-active molecules in the soap,the long-term controllable movement of the device can be achieved by controlling the pH based on the realization of long-term motion.Then,based on the above work,a pH response system was used to achieve controlled decomposition of supra-amphiphiles,and they were dynamically decomposed into two types of hydrophilic/hydrophobic molecules under pH response,thereby decomposing the surfactants of the surface adsorption layer.For this purpose,we used a hydrophobic motif with an amino group and a hydrophilic motif with an aldehyde group to synthesize an supra-amphiphile with an imine bond.We designed an "aluminum foil boat" system and observed the effect of solution pH on the Marangoni movement..By regulating the pH,the super-amphiphilic molecules realize the long-term motion of "aluminum foil boat" on the surface.Based on the supra-amphiphiilic molecule strategy,the above problems are solved effectively,which opens up new ideas for further research and development based on the Marangoni motion and brings new research solutions for the development of self-driven smart devices.