Scanning electron microscopy porosity determination

Therefore, it is anticipated that an increase in the granulometric size of the SDDP particles during scale up will probably not effect the SDDP particles dissolution rate of the powder as long as the texture of the SDDP is not modified Hence the critical parameters to be followed during scale up are the internal porosity and the intraparticular pore diameter as determined by Mercury Intrusion Porosimetry or by Scanning Electron Microscopy... 

In this work, we report on the preliminary results from the fabrication and characterization of Ni-AbOs membranes. The effect of sintering temperatures on membrane support was investigated. The fabricated membranes were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer including X-ray mapping (EDS). In addition, the pore size and porosity were determined by Hg porosimetry. 

The microstructures of the Ti02 sheet cross-section were observed by scanning electron microscopy (SEM), and the phase composition was confirmed by X-ray diffraction (XRD). The porosities of the samples were determined by Archimedes method. 

Sing KSW, Everett DH, Haul RAW, Moscou L, Pierotti RA, Rouquerol J, Siemieniewska T (1985) Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity. Pure Appl Chem 57(4) 603-619 Stevens SM, Jansson K, Xiao C, Asahina S, Klingstedt M, Gruner D, Sakamoto Y, Miyasaka K, Cubillas P, Brent R, Han L, Che S, Ryoo R, Zhao D, Anderson M, Schuth F, Terasaki O (2009) An appraisal of high resolution scanning electron microscopy applied to porous materials. JEOL News 44(1) 17-22... 

The porosity (ie, pore size and amount of pores) of microparticles is also an important characteristic to take into consideration when fabricating microparticles because it plays an essential role in controlling the release of payloads. The porosity and morphology of particles are usually determined by scanning electron microscopy (SEM). For the emulsification solvent extraction/evaporation method of fabrication, the rate of solvent extraction, which depends on the flow in the stirred vessel the droplet size the temperature and the dispersed phase hold-up in the 0/W emulsion have an effect on porosity [87]. The porosity usually increases with a decrease in solvent extraction rate. The porosity of microparticles results in initial burst release due to pore diffusion [78,88]. Mao et al. studied the influence of different W/O/W emulsification solvent extraction/evaporation process parameters on internal and external porosity of PLGA microparticles [78]. The surface morphology of the microparticles can be influenced by the type of polymer, internal aqueous phase voliune (Wi), volume of continuous phase (W2), polymer concentration, homogenization speed, and equipment used for the primary emulsion [78,79]. 

Porosity and pore-size distributions were determined by gas adsorption and immersion calorimetry, with the measurement of helium and bulk densities. Volumes of micropores were calculated using the Dubinin-Radushkevich (DR) equation (Section 4.2.3) to interpret the adsorption isotherms of N2 (77 K), CO2 (273 K) and n-C4H o (273 K). Volumes of mesopores were evaluated by subtracting the total volume of micropores from the amount of nitrogen adsorbed at p/p° = 0.95. The two density values for each carbon were used to calculate the volume of the carbon skeleton and the total volume of pores (including the inter-particle space in monolithic disks). Immersion calorimetry of the carbon into liquids with different molecular dimensions (dichloromethane 0.33 run benzene 0.37 nm and 2,2-dimethylbutane 0.56 nm) permits the calculation of the surface area accessible to such liquids and subsequent micropore size distributions. The adsorption of methane has been carried out at 298 K in a VTI high-pressure volumetric adsorption system. Additional techniques such as mercury porosimetry and scanning electron microscopy (SEM) have also been used for the characterization of the carbons. 

Powder X-ray diffraction (XRD) data were collected via a Siemens D5005 diffractometer with CuKa radiation (A. = 1.5418 A). Routine transmission electron microscopy (TEM) and Z-contrast microscopy were carried out using an HITACH HD-2000 scanning transmission electron microscope (STEM) operated at 200 kV. Nitrogen gas adsorption measurements (Micromeritics Gemini) were used to determine the surface area and porosity of the catalyst supports. Inductively coupled plasma (ICP) analysis was performed via an IRIS Intrepid II XSP spectrometer (Thermo Electron Corporation). 

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