Research On Controllable Preparations,Structure And Performances Of Novel Composite Hydrogels Based On MIL-101

Due to the unique 3D network microstructure and physical/chemical properties,hydrogels show great potential in the fields like environmental protection,flexible electronics,energy store and medical treatment.However,traditional hydrogels have poor mechanical properties and functions,which severely limit the practical application of hydrogels.In order to improve the mechanical properties of hydrogels,researchers have used inorganic nanoparticles as the reinforcing phase to develop nanocomposite hydrogels(Nanocomposite Hydrogels,NCs)with high mechanical properties.However,due to the poor compatibility with polymers,low functionality and adjustability of common inorganic nanoparticles,the mechanical properties and functionality of nanocomposite hydrogels cannot be further improved.Therefore,it is necessary to investigate new nanoparticles as nanofillers to improve the mechanical properties and functionality of nanocomposite hydrogels.Metal-organic frameworks(Metal-Organic Frameworks,MOFs),as the organicinorganic hybrid materials composed of metal ions or clusters and organic ligands,have good compatibility with polymers,high functionality and modifiability.To serve as nanofillers of nanocomposite hydrogels,MOFs nanoparticles have natural superiority.Based on this,this paper used MOFs as nanofillers,and applied two different polymerization methods to prepare two novel types of MOF-laden nanocomposite hydrogels with high MOFs contents and mechanical properties,MIL-101/PAAm(MIL-101/Polyacrylamide)and MIL-101-MAAm/PAAm(MIL-101-MAAm/Polyacrylamide).First of all,in-situ polymerization was applied to prepare MIL-101/PAAm nanocomposite hydrogels.Due to the strong interaction between MIL-101 and PAAm polymers chains through hydrogen bonds and coordination unsaturated metal sites(CUS),MIL-101/PAAm possessed the dense and uniform microstructure and excellent mechanical properties.It could withstand more than 500% tensile strain,90% compressive strain and MPa-level stress.In addition,MIL-101/PAAm also had excellent thermal stability and certain response to p H.Secondly,on the basis of MIL-101/PAAm,based on the high functionality and modifiability of MOFs,post-synthetic modification(PSM)method was used to prepare MILMAAm,which possessed polymerizable functional groups and hydrophilic functional groups.Then,MIL-101-MAAm/PAAm nanocomposite hydrogels were prepared by post-synthetic polymerization(PSP)method.Due to the unique polymerization mechanism,MIL-101-MAAm/PAAm possessed the unique three-dimensional“pearl-net”microstructure and excellent mechanical properties,and formed the strong chemically covalent interactions between MIL-101-MAAm and PAAm polymer chains,in addition to the strong interactions formed through hydrogen bonds and coordination unsaturated metal sites.It could withstand more than 500%tensile strain and 90%compressive strain,but also had excellent elasticity and recovery.Besides,MIL-101-MAAm/PAAm also showed response to temperature and p H,and anti-freezing performance.In this paper,two novel types of MOF-laden nanocomposite hydrogels were successfully prepared by the two different methods described above,and the hydrogels with highly mechanical and multifunctional performance was achieved,which was of significance to the development of new highly mechanical multifunctional nanocomposite hydrogels.