The Setup Of In Situ Monitoring System And Study On Aggregation Structure Of Langmuir Monolayer At The Air-Water Interface

Nowadays, the major direction in the study of LB technique is how to use it construct nano-structure ordered functional system and then develop new type nano- structure materials with good performance. In order to study the influence of film structure property on its specific function, Scientists recently have paid much more attention to the process of molecule aggregation and phase transition in the Langmuir monolayer at the air-water interface. Many kinds of sensitive surface analyzing techniques have been developed to investigate this process in the film. With its perfect sensitivity to the change of interfacial structure, surface enhanced Raman scattering technique can offer us lots of information at the molecule level and become a powerful method in the study of Langmuir monolayer. Based on above research backgroud, a complete in situ Raman test and CCD monitering system was designed and set up in our lab, which including a micro-Raman spectrometer, a mini Languir trough designed and manufactured by ourself, a CCD imaging system. We can obtain information about process of film compression and phase transition in the film at the molecule level. The work we have carried out is as below: Fristly, we obtained Raman spectrum of ODA Langmuir monolayer on Ag sol. With the in situ micro imaging study of Langmuir monolayer on Ag sot, we proved that QDA molecule has a very strong interaction with Ag nanoparticle, which induced Ag nanoparticle aggregationg below the ODA Langmuir monolayer. Because Ag sol is SERS-active, we can obtain the SERS of QDA monolayer. In additon, we mixed ODA molecule with Lecithin, formed a composite film on Ag sol. Then we obtain SERS of lecithin molecule because of interaction between Ag particle, and ODA molecule in the V mixed film. Our experiment indicated that by mixing ODA molecule with other material, we can obtain many material抯 SERS spectrum on Ag sol. It testified that this method has a widely use. Secondly, we study the compression and phase transition process of ODAllecithin mixed film by ~t -A isothems and in situ CCD monitoring system. Then we expanded our research object to biological material Chla-Zn and DDP-FeS nanoparticle. In this way, we observed the aggregation process of different Langmuir film directly. Using 7E -A isothems amd AFM measurment, we investigated the interaction of spread lecithin monolayer with amino acid in the aqueous solution, we found that the average area per molecule increased with the adsorption of amino aced molecule. By transferring Langmuir monolayer to mica, we observe the crastalizing and growing process directly with AFM imaging system.