Preparation Of Through-hole Porous Anodic Alumina And Its Application In The Recognition Of Sugar Enantiomers

With the development of nanotechnology, the structure controllable preparationof porous anodic alumina (PAA) has attracted increasing attentions in recent years.Due to its uniform morphology, controllable pore diameter and stablephysicochemical property, PAA membrane has good performance in various fieldssuch as preparation of functional nano-materials, catalyst, separation and biosensing.Ion channels, which play an important role in the physiological functions of cells bymodulating the penetration of nutrients and ions across cell membranes, arecharacteristic with small size, high selectivity, as well as stimulus responsive property.PAA membrane, due to its chemical stability, thermal resistance, high mechanicalstrength and good dimension stability, is suitable for immobilization of functionalmolecule to imitate the superior functionalities of the ion channels in the livingsystems. The intelligent design and functional modification of PAA membranes, isexpected to provide new ideas for development of biosensors and construction ofartificial ion channels.In this thesis, we systematically studied the fabrication techniques of PAA byanodization in phosphoric acid. The anodizing process was carried out at differentanodizing voltages, tempuratures for different time. The suitable conditions have beenobtained to prepare the structure controllable through-hole PAA membranes.Theresults show that in anodic oxidation process, oxidation temperature and oxidationtime mainly affect the regularity of the membrance, appropriately increasing thetemperature and oxidation time, porous anodic alumina ordering further. Anodizingvoltage greatly influences the interpore distance of PAA membrane, the interporedistance increased and pore density decreased with anodizing voltage increased. Thepore opening process uses chemical etching method to remove the barrier layer and toachieve through-hole PAA membrance. Meanwhile, the pore diameter of PAAmembrane will increase obviously through this process.We then focused on the intelligent design and functional modification of PAA membrance to devise chiral-saccharides-responsive nanodevices. Inspired by thestereoselectively interaction between L-dipeptide and monosaccharide enantiomers,we designed and synthesized a three-component smart copolymer containingdipeptide units, functional units, and mediating units, to translate the chiralrecognition signs into differential conformational changes of copolymer chains. Thechiral polymers were grafted to the surface or channel of the PAA membrane by“grafting to” strategy. The electric voltage-current curves of free ions through thePAA membrane in different saccharide-environment were measured to evaluate theresponsive property of this artifical intelligence channel.