Study On The Temperature-response Release Of (PAH/SiO2)-(PAH-rGO/PNIPAM) Self-assembled Multilayers

The structure of the stimulation-responsive materials contains many special groups that have special properties.They are capable of responding specifically to one or more minor physical or chemical changes from the external environment,because of the special groups within their molecular structure.Their physical and chemical properties will change,when the materials are stimulated by the external environment.Environmental stimuli-responsive polymers can be considered as a soft substance and classified into three types according to the type of environmental stimuli:?a?physical stimuli,?b?chemical stimuli,and?c?biochemical stimuli.Poly?N-isopropylacrylamide?has attracted wide attention due to its special response temperature and molecular chain configuration.It is in the field of self-healing materials,responsive materials,memory materials and nanomedicines.It has a wide range of applications,such as immunodetection of the human body,targeted drug delivery,recovery of various enzymes,and the like.In this study,PAH-rGO/PNIPAM and?PAH/SiO₂?-?PAH-rGO/PNIPAM? multilayer films were prepared by layer-by-layer self-assembly techniques using PNIPAM in combination with reduced graphene oxide.Due to the assembly of the PNIPAM component in the multilayer film,the multilayer film has a temperature-response performance.When the ambient temperature is above or below the critical phase transition temperature of PNIPAM,the multilayer film will exhibit different physicochemical properties.In this paper,the following work is mainly carried out:?1?The PAH-rGO/PNIPAM multilayer film was prepared by a layer-by-layer self-assembly method using an amide group on the side of a PNIPAM molecular chain and an amino group on the surface of a PAH.The multilayer film has good stability and can be stably present in environments of an acidic,alkaline and high temperature deionized water.It also exhibits different hydrophilic and hydrophobic properties and particle permeability at different temperatures.?2?The?PAH/SiO₂?-?PAH-rGO/PNIPAM?multilayer film was prepared by combining a PAH-rGO/PNIPAM multilayer film on the PAH/SiO₂ film.In the multilayer film,the PAH/SiO₂ component is used as a load component,and the PAH-rGO/PNIPAM component is used as a temperature-response functional component.Differential release for molecules at different temperatures can be achieved by this film.By controlling the number of PAH-rGO/PNIPAM bilayers in the?PAH/SiO₂?-?PAH-rGO/PNIPAM?multilayer film,the regulation of the release rate and total release of small molecules is achieved.?3?Combined with the differential release of molecules by?PAH/SiO₂?-?PAH-rGO/PNIPAM?multilayer membrane,a simple synthesis control of CaCO₃ was designed,which provided a new method for the regulation of nanoparticle morphology.