|
Nanoparticle self-assembly has unique physical and chemical properties, and thus the self-assembly technology has been a concern, and good prospect of application in medicine, sensing, chemical separation. However, previous studies on the assembly methods and assembly technology research more about the assembly mechanism is unclear. Optical fiber sensing technology for its anti-electromagnetic interference, electrical insulation, corrosion-resistant, intrinsically safe, high sensitivity, light weight, small size, shape variable, measurement object range, low cost and unique advantages of being a wide range of great importance and can be widely The applied rotation, vibration, temperature, current, electric field, magnetic field, pressure, and other physical parameters of the measurement. , Depending on the working principle, the optical fiber sensor has a different structure and operating mode. The departure from the nano thin film growth mechanism and optical fiber sensor design work, the main contents and results are as follows: (1) improvement of the method of synthesis of spherical gold nanoparticles. On the basis of the original seed crystal growth method, by changing the proportion of the reducing agent / chloroauric acid, the reaction was added at a rate, we optimize and improve the crystal growth method. The improved seed crystal growth method can be used for the preparation of a larger particle size spherical gold particles, and the shape more regular, more uniform particle size. (2) research the emulsion droplets fuse to form the nanoparticle film and film along the vessel wall climbing physical mechanism. The study found that in the aqueous phase formed after the emulsion droplets, the nanoparticles to the oil droplets - water interface adsorption into incompetent barrier hindered diffusion controlled process. Thus by ultrasound and increase total oil - water interface way (through the formation of the emulsion) to improve the adsorption of nanoparticles to the interface transfer coefficient. Adsorption load the nanoparticle emulsion droplets instability spontaneously demulsification the nanoparticles released into the flat water - oil interface, leading to the formation of nanoparticles film. The emulsion droplets demulsification fusion process, the curved surface to generate additional pressure, resulting in a pressure gradient generated in the interface nanoparticle film, thereby to drive the film along the vessel wall climbing. (3) designed to prepare a fiber pH sensor based on surface-enhanced Raman scattering (SERS). High SERS-active silver nanoparticles assembled in the optical fiber end face preparation of SERS-active fiber end face, and then 4-mpy pH-sensitive probe molecule is adsorbed to the silver nano-particles formed SERS fiber pH sensor. PH changes the ,4-mpy molecular structure with the environment will change, corresponding SERS spectrum will also change. The 4-mpy molecule SERS spectral characteristics can be used to indicate the solution to be measured pH. At pH = 0-3 range for the most sensitive of the two peaks for H ,4-mpy 1610 cm-1 and 1575 cm-1 peak area ratio with increasing pH of the solution is weakened, at pH = 0-2 range, the area of ??the two peaks have a good linear relationship between the number and pH, and not subject to the influence of the ionic strength of the solution. This sensor is expected to be used online, in situ, and long-distance acidic environment pH detection.
|