Study On Stability Of Fluorinated Organic Porous Materials In Humid Environment

Porous organic materials are composed of light elements via covalent bonds.There are two main types of synthesis methods,one is irreversible reaction,which could form stable covalent bonds;the other one is reversible reaction,the resulting covalent bond is poor in stability and is easily decomposed in water vapor strong acid strong alkali environment.Air is the common environment in the use of porous materials.The water vapor is the main factor that affects the stability of structure.Therefore,it is of practical significance to explore the stability of porous organic materials in humid environments.First,considering the influence of material synthesis methods on the formation of chemical bond;second,considering the influence of the surface wettability of materials.The variety of factors is combined to explore the stability of porous organic materials in humid environments.The fluorinated porous organic materials(PAF-11-Xs)were constructed,and the stable chemical bond was formed by Suzuki reaction,which represent the porous frameworks obtained from irreversible reaction.With the increase of fluoride content,the specific surface area of resultants gradually decreases,and the hydrophobicity gradually increases.Different relative humidity environments were chosen to test the stability of PAF-11-Xs materials.It was found that the chemical bonds of PAF-11-Xs material are very stable.The hydrophilic porous organic materials C-Xs are constructed,and the Schiff base reaction is used to generate unstable chemical bonds.After the introduction of fluorine atom,the quality of materials changes from hydrophilic to hydrophobic.In a humid environment,the C-1 and C-3 materials which have no fluorine atoms are unstable.The C-2 and C-4 materials which are doped with fluorine atoms are comparatively stable.The hydrophobicity of C-Xs increases after incorporated the fluorine atom,which reduces the damage induced from water molecule to the skeleton and improves the stability of the samples in a humid environment.The super-hydrophilic porous organic materials(SNW-Xs)are constructed via an irreversible amine condensation reaction.After incorporated different proportions of fluoride atom,the surface wettability of SNW-Xs has no significant change,and they can be stable present in a humid environment.The water molecules have no damage to the chemical bonds of SNW-Xs,so that it can be stabilized in the humid environment.