Isothermal heat conduction microcalorimetry was utilized as a novel characterization method to investigate the polymerization processes of silica with both thermodynamic and kinetic parameters when the combination of silica sol and potassium silicate was stirred at temperatures of 25.0, 35.0, and 45.0 ℃. The silica polymerization was characterized by the greater enthalpy change at each higher temperature and by the reaction orders of the silica sol and potassium silicate, which varied rapidly, instantaneously, and constantly from low to high all the time, up and down in an alternate manner. When the reaction order of the silica sol and potassium silicate was 3.0, the maximum rate constant occurred at 25.0℃ （k= 1.22 × 10 ^-4 mol-2·dm6·s-1）. The two temperature regions （25.0-35.0 ℃ region with a faster rate and 35.0-45.0℃ region with a lower rate） reflected a two-stage oligomerization of silica monomers with different oligomers formed in a two-step anionic mechanism. The measurements of particle size and pH value showed that the colloidal particles in the mixed silica sol and potassium silicate first dissolved, then ＂active＂ silica in the potassium silicate redeposited to make a distinct particle size distribution （Z-average size, 33.0-14.9 nm at 25.0 ℃） influenced both by pH value （9.82--11.97 at 25.0 ℃） and the mass fraction （53, 65, 75, and 85 mass/%） of the silica sol in the mixture. The processes of combination of the silica sol and potassium silicate did not result from acid-base neutralization reactions but from a complex polymerization of the ＂active＂ silica components which relate to silica monomers oligomerization with heat evolved （the total enthalpy changes, 1.6234-3.3882 J）.
基于Si—O—C结构,合成了一种新型水敏感的Y型两亲性聚合物,研究了其在无水环境下的自组装行为。以水诱导组装体形成,研究了该物质的水敏感程度。结果表明,在0.6 m L/min的诱导速率及70%水含量下,合成的Y型两亲性聚合物自组装形成多层囊泡结构,这种多层囊泡具有一定的水解稳定性,且具有温敏性和p H响应性。
