The Study On The Glass Nanopore Modification With Zirconium Phosphate Assembled Multilayer

Nanopores with unique mass transport properties have attracted lots of attentions due to their potential applications in DNA sequencing,protein detection,chemical sensing and biomimetic ion channel constructions.Materials that can be used for nanopore fabrication include nanopore bearing natural/mutated proteins as well as inorganic solid materials.Although protein-based nanopores have been successfully used for DNA sequencing,they have shortcomings that are difficult to overcome in terms of physical and chemical stability.On the other hand,solid-state nanopores showed promising prospects because of their facility for mass production,stable physical and chemical properties,customizable dimension and easy functionalization.Conventionally,solid nanopores can be made of various materials such as silicon nitride,polymer,glass capillaries,alumina oxide and graphene.And various approaches have been proposed for fabricating these nanopores.For example,ion beam etching and electron beam etching have been applied for the fabrication of silicon nitride nanopores;track etching,electrochemical breakdown and template based method have been used for constructing polymer membrane nanopores;and glass capillaries can be pulled to form nanopores.However,it is still challenging to accurately adjust nanopore size without the help of expensive equipments such as electron beam and ion beam.Moreover,the nanopore size has a very important influence on its properties and functions.Thus,it is of great significance to propose a facile and universal method that can precisely control the inner diameter in nanoscale for glass capillary pulled nanopores.Zirconium phosphate compounds are a class of multifunctional materials that can form ordered layered structure and widely used in electrochemistry,adsorption,catalysis and medicine due to their regularity,chemical stability and molecular designability.1,10-decanebisphosphate and ZrOCl₂ can form a stable and well oriented multilayer thin films with certain thickness by coordination.Therefore,based on this assembly,it is promising to precisely adjust the glass nanopore inner diameter.The main contents and results of this work are as follows:1.1,10-decanebisphosphate was chemically synthesized by 1,10-dibromodecane and triethyl phosphite without catalyst according to the Michaelis-Arbuzov principle and hydrolysis reaction.The performance index was tested and the molecular structure was characterized by nuclear magnetic resonance and infrared spectrum,which showed that the synthesized product was 1,10-decane diphosphate.2.After surface hydroxylation and phosphorylation,silicon wafers were alternately modified by ZrOCl₂ and 1,10-decanebisphosphate and the zirconium phosphate films that were produced by different reaction concentrations and reaction times were investigated.The thickness of the film wasmonitored by ellipsometry and the surface topography was characterized by atomic force microscopy,which showed that there existed a good linear relationship between the film thickness and the assembly number and the multilayer was homogeneous and ordered.3.A laser capillary puller was used to fabricate a glass nanopore and zirconium phosphate based assembly film was employed to modify the glass nanopore.I-V curves in the range of-1 to1 V were measured by an electrochemical workstation.The electrochemical measurement based equivalent inner diameter of the nanopore was calculated and its relationship with the modification layer number was plotted.The I-V curves of the modified nanopore under different pH values were also investigated.The results indicated that the multilayer films can effectively modifying the nanopore and accurately regulate the inner diameter.