ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Rhodamine B (RB)-doped and monodispersed spherical particles of polyorganosiloxane were synthesized by a sol–gel method from methyltrimethoxysilane (MTMS) using a reaction field of W/O emulsion that was formed from a hydrophobic solution of sorbitantrioleate (SPAN85) plus n-octane, and an aqueous solution of RB. Three different methods of introducing MTMS into the solution were examined. In the first method, MTMS was added only to the hydrophobic solution of SPAN85 and n-octane. Although monodispersed spherical particles were synthesized by this method, RB was hardly doped in the spherical particles. In the second method, RB could be doped in spherical particles by introducing MTMS only into the aqueous solution of RB. However, the particle was not monodispersed, and several of pores were present in the particles, which was probably because of a deficiency of silanols in the water droplets in the emulsion. In the third method, above two methods were used together to obtain RB-doped and monodispersed spherical particles. Moreover, the pores in the particles were remarkably decreased. This is probably because sufficient amounts of silanols were supplied to the water droplets from the oil phase. The content of RB in the particles was different among the three methods. To incorporate RB into the spherical particle, the interaction between RB and silanol was found to play an important role. The RB-doped spherical particles were heat treated up to 600°C, and the thermal stability of RB was determined. In RB-doped spherical particles, transformation of T2 into T3 at 200°C was prevented and Si–OH still remained. Fluorescence was still observed in the RB-doped spherical particles heat treated at a high temperature of 350°C. Therefore, RB was considered to be incorporated tightly into the silica matrix containing Si–CH3. From the above results, we discussed the formation mechanism of RB-doped spherical particles.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1551-2916.2005.00607.x
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