A fractal description of pore structure in block-copolymer templated mesoporous silicates

作者：Smith Michael A^*; Lobo Raul F

来源：Microporous and Mesoporous Materials, 2010, 131(1-3): 204-209.

DOI：10.1016/j.micromeso.2009.12.023

• Mesoporous silicate
• Fractals
• Surface fractal
• Nitrogen adsorption

Traditional nitrogen physisorption isotherm analysis of triblock copolymer mesoporous silicates interprets the pore structure as a bimodal distribution of mesopores and smaller micropores. Samples of SBA-15, SBA-16 and SBA-11 were prepared and calcined between 300 and 900 degrees C. Adsorption analysis using a fractal Frenkel-Halsey-Hill approach reveals an alternative interpretation, that the micropores are a manifestation of the fractal silica - polyethylene oxide polymer interface. We show that calcination at higher temperatures is effectively an annealing process that smoothes the mesopore surface, such that by 900 degrees C the surface dimension is similar to 2. We also use the well-characterized pore structure of SBA-15 and related silicates to examine and discuss several different methods for extracting the fractal dimension from isotherm data.

• 出版日期2010-6