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The loading of copper porphyrin (CuTCPP) onto the surface of silver nanowires can be achieved through covalent bonding loading method or physical adsorption method. The specific scheme needs to be optimized in combination with the surface characteristics of silver nanowires, the chemical structure of CuTCPP and the target application scenarios. The following are detailed descriptions of two methods:
I. Covalent Bond Loading Method
The covalent bond loading method achieves a firm combination by forming covalent bonds between silver nanowires and CuTCPP molecules, which can prevent CuTCPP from falling off and improve loading stability.
Surface Functionalization Treatment:
The surface of silver nanowires is modified to introduce active functional groups such as amino and carboxyl groups. For example, using polyvinylpyrrolidone (PVP)-coated silver nanowires, the carbonyl groups in the PVP molecules on the surface can react with amino compounds to generate amino-functionalized silver nanowires.
Carboxyl groups can be introduced on the surface of silver nanowires through oxidation treatment (such as using hydrogen peroxide).
Covalent Bond Formation:
The carboxyl groups in CuTCPP molecules are connected to the amino-functionalized silver nanowires through amide bonds. Specifically, the carboxyl and amino groups undergo condensation reactions under the action of a catalyst (such as EDC/NHS) to form stable amide bonds.
If carboxyl groups are introduced on the surface of silver nanowires, they can be connected to the hydroxyl groups in CuTCPP molecules through esterification reactions. However, it should be noted that CuTCPP molecules usually do not contain hydroxyl groups, so CuTCPP needs to be chemically modified to introduce hydroxyl groups or other functional groups that can react with carboxyl groups.
Optimization Conditions:
Control the reaction temperature, pH value, and reaction time to improve the efficiency of covalent bond formation. For example, the formation of amide bonds usually occurs at room temperature to 50°C, with the pH value controlled between 7 and 8.
Adjust the molar ratio of silver nanowires to CuTCPP to obtain the optimal loading amount.
II. Physical Adsorption Method
The physical adsorption method utilizes non-covalent interactions (such as hydrogen bonds, hydrophobic interactions, or electrostatic interactions) between silver nanowires and CuTCPP molecules to achieve loading. This method is simple to operate, but the loading stability is greatly affected by the environment.
Surface Pretreatment:
Clean the silver nanowires to remove surface impurities and unreacted reagents.
Optionally, perform surface activation treatment on the silver nanowires, such as plasma treatment or ultraviolet irradiation, to increase surface active sites and improve adsorption capacity.
Physical Adsorption Process:
Disperse the pre-treated silver nanowires in a solution containing CuTCPP, and promote adsorption through stirring, ultrasonic treatment, etc.
Adjust the pH value, ionic strength, and temperature of the solution to optimize the adsorption effect. For example, under acidic conditions, the carboxyl groups in CuTCPP molecules may carry a negative charge and undergo electrostatic adsorption with the positively charged surface of silver nanowires.
Post-treatment:
After adsorption is complete, remove unadsorbed CuTCPP molecules through centrifugation, washing, etc.
Optionally, perform drying treatment on the loaded silver nanowires to obtain solid samples.
