Study On Preparation Methods Of Metal-Organic Framework Films Based On Self-assembly And Electrophoresis

Metal-organic frameworks(MOFs),also named porous coordination polymer(PCP),are porous crystalline materials coordinated by metal ions/clusters and organic ligands.Because of their exceptional features,including large surface area,regular but tunable pore size,chemical tailorability,excellent chemical and thermal stability,MOFs have been intensively studied and shown great potentials in many applications,for instance,gas storage/separation,chemical sensing,drug delivery,and catalysis.During the past decades,lots of researches have been performed in the synthesis,morphology/size control of MOF crystals,and the preparation of MOF films.The performance of MOF films is superior to that of powders in some specific applications,such as gas separation and chemical sensing.To date,lots of methods have been developed for preparing MOF films,and these methods can be divided into ex situ and in situ methods.This paper aims at two basic scientific problems existed in the preparation methods of MOF films,namely,self-assembly of monodispersed MOF crystals to ordered films in ex situ methods and confined nucleation and growth of MOF films in in situ methods,and we proposed two original solutions.Based on reasonable experimental design and MOF material selection,we revealed the key factors that influence the self-assembly of monodispersed MOF crystals to ordered films and verified that the electric field did boost the confined MOF nucleation and growth on the electrode to realize controllable growth of MOF films by systematically studying.The details are shown as follow:(1)Study on self-assembly of monodispersed MOF crystals to ordered films.Preparing monodispersed UiO-66 crystals with uniform morphology and controllable size through an acid-base co-modulation strategy,and modifying the as-prepared UiO-66 crystals with modifiers.On this basis,assembing the modified UiO-66 crystals by solvent evaporation,and exploring the key factors that influence the self-assembly of MOF crystals.(2)Study on electrophoresis-assisted growth of ZIF-8 films.Taking ZIF-8 crystals as the research object,optimizing the reaction conditions without an applied external electric field,and constructing conductive/insulating electrodes.On this basis,preparing ZIF-8 films under the external electric field,and exploring the effects of reactant concentrations,molar ratios,electric filed intensity,thicknesses of the insulating layer and reaction time.(3)Study on anodic dissolution preparation of M-CAT films.Taking the conductive Cu-CAT for example,designing and constructing different Cu electrodes,and using them for anodic dissolution preparation of Cu-CAT films.