Determination Of Pore Size Research Articles

SNARE Copy Number Determines the Size and Kinetic Properties of Nascent Fusion Pores

The first step in neurotransmitter and hormone release is the formation of a fusion pore. Capacitance measurements revealed that pore size can range from 0.5 to 2 nm in neuroendocrine cells. However, the mechanisms that determine pore size and dynamics are largely unknown due to the low abundance and ephemeral nature of these crucial structures. Here, we reduced the number of available SNAREs in neurons and observed changes in transmitter release suggestive of alterations in fusion pore properties. To address this possibility, we first employed reconstituted nanodisc/liposome-based fusion assays, using optical sensors to detect cargo flux through nascent pores. Ensemble and single vesicle measurements revealed that increasing the number of SNARE complexes enhances the rate of release of a given cargo, and enables the escape of larger cargos. To determine whether this was due to changes in pore size versus stability, we developed a novel reconstitution approach, based on nanodiscs and planar lipid bilayer electrophysiology, that affords µsec time resolution at the single event level. Remarkably, both parameters were affected by SNARE copy number. Increasing the total number of v-SNAREs per nanodisc from three to five caused a two-fold increase in pore size and decreased the rate of pore closure by two orders of magnitude. Moreover, trans-SNARE pairing was dynamic as perturbation of v-/t-SNARE zippering disrupted the stability of fusion pores, particularly at the base of the SNARE complex. In summary, trans-SNARE complexes are metastable and the number of SNAREs recruited to drive fusion dictates fundamental properties of individual pores.

Effect of pyrolysis process parameters on electrical, physical, chemical and electro-chemical properties of SU-8-derived carbon structures fabricated using the C-MEMS process

Pyrolysis is the process to thermally decompose an organic material into its carbon backbone in an oxygen-free environment. This process is used in the Carbon-MEMS fabrication technology to carbonize micro-structures patterned on a substrate. The properties of the resulting carbon material are dependent on either the carbon precursor or the pyrolysis conditions. In this work, SU-8 photoresist was used as the carbon precursor to study the effects of three pyrolysis parameters: 1) maximum pyrolysis temperature (600°C, 700°C, 800°C, and 900°C), 2) temperature ramp rate (2.5°C/min, 5°C/min, 10°C/min, and 20°C/min), and 3) nitrogen flow rate (3l/min, 4.5l/min, 6l/min, and 7.5l/min). To studythe effect of the maximum temperature, the temperature ramp rate and nitrogen flow rate were kept constant to 5°C/min and 6l/min respectively. For the temperature ramp rate experiments, we kept the maximum pyrolysis temperature and nitrogen flow rate constant to 900°C and 6l/min respectively. For the nitrogen flow rate study, the maximum pyrolysis temperature and temperature ramp rate were kept constant to 900°C and 5°C/min respectively. We found that no polymer structures persisted under the following conditions: 900°C maximum pyrolysis temperature, 5°C/min temperature ramp rate, and 3l/min nitrogen flow rate. Under these conditions the nitrogen flow rate is not high enough to keep the furnace environment (approximate volume of the furnace tube we used is 6l) entirely inert; in the pyrolysis process, even a small amount of oxygen destroys the intended C-MEMS. All the carbon samples were characterized using 4-point probe measurement for electrical resistivity; confocal microscopy for pore size determination; Raman spectroscopy, electron diffraction x-ray spectroscopy (EDX), and x-ray photoelectron spectroscopy (XPS) for chemical characterization. Furthermore, the samples were electrochemically characterized using cyclic voltammetry in a 1mM K4Fe(CN)6 and 0.5M KCl solution. The characterization results suggest that samples prepared under the following conditions - 900°C maximum pyrolysis temperature, 5°C/min temperature ramp rate, and 6l/min nitrogen flow rate, exhibit the best electrical, physical, chemical and electrochemical properties among the other conditions used.

Fibril growth kinetics link buffer conditions and topology of 3D collagen I networks.

The study reports a comprehensive analysis of physicochemical conditions of buffer solutions to reconstitute defined 3D collagen I matrices. By a combined analysis of network topology, i.e., pore size and fibril diameter, and the kinetics of fibril formation we can reveal the dependence of 3D network topology on buffer conditions, such as pH-value, phosphate concentration and sodium chloride content. With those results we are now able to provide engineering strategies to independently tune the topology parameters of widely used 3D collagen scaffolds based on the buffer conditions. By that, we enable the straightforward mimicking of extracellular matrices of in vivo tissues for in vitro cell culture experiments and tissue engineering applications.

In situ determination of pore sizes of high density polyester woven fabrics under biaxial loading

In this study an in situ pore size measurement method was developed to determine the pore size changes of high density polyester woven fabrics under biaxial loading. This unique method allows the non-destructive testing of the pore sizes under biaxial loading. Changes in the pore size distributions of samples were in situ determined with the newly developed method. The results show that the developed measurement method is very promising to define the pore size changes of barrier textiles in situ under loading.

Tuned apatitic materials: Synthesis, characterization and potential antimicrobial applications

Inorganic antimicrobial materials can be viable for multiple applications (related to its use for new buildings with special requirements related to microbiological loading, such as hospital buildings and for consolidation of cultural heritage constructions); also the use of substituted hydroxyapatites for protection of stone artefacts against environmental factors (acidic rain) and biodeterioration it’s an option to no longer use of toxic substances. This paper presents methods of synthesis and characterization of the material from the point of view of the obtained structures and final applications. The materials were characterized in terms of composition and morphology (using X-ray Diffraction, X-ray Fluorescence, Inductively coupled plasma-atomic emission spectrometry, Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, Surface area and pore size determination). Antimicrobial activity was tested against filamentous fungi strains and pathogenic bacteria strains, using both spot on lawn qualitative method (on agar medium) and serial microdilution quantitative method (in broth medium). Further, it was evaluated the anti-biofilm activity of the tested samples toward the most important microbial strains implicated in biofilm development, using crystal violet stained biofilms microtiter assay, followed by spectrophotometric quantitative evaluation.

Membrane impedance porometry

In this work a new method named impedance porometry is described to determine the pore size distribution of microfiltration membranes without flow measurements. Instead, this method uses measurements of the electric (ion) current to quantify the number of pores of a certain size in which fluid displacement has taken place and ion conduction can take place. The impedance porometry method exhibits distinct advantages over classical flow porometry methods. First, the correlation used to determine pore size distributions from impedance measurements correlates to the transmembrane pressure by one power less (Δp4) compared to the function using fluid flow (Δp5). Therefore, it is less affected by errors in measuring as well as regulating the transmembrane pressure. Secondly, the proportionality factor, K1, between pore radius and fluid displacement pressure is two powers smaller (K13) compared to the one of conventional flow porometry methods (K15). And finally the impedance may be determined with 250 fold precision compared to flow rates. The mean pore radii determined with the new method are larger compared to the ones determined by conventional flow porometry.By comparing hydraulic flow and electrical admittance measurements as well as comprehensively reviewing the literature of flow porometry and fluid displacement from porous media, we argue that often the mean pore sizes are underestimated in classical flow porometry methods. More importantly, combining flow and impedance porometry, contact angles and surface tensions values do not need to be assumed anymore because both experimental methods and theoretical interpretations are affected differently by these values. Hence by combining the two methods these values in fact can now be determined precisely. This work also suggests that values from flow porometry published during the past decades need to be taken with caution. We also suggest to revisit the analysis of membrane pore size distributions using combined methods to reduce the effect of far-reaching assumption as made in classical flow porometry.

Analytical model for straining-dominant large-retention depth filtration

A method for determining pore size distribution for a porous medium from long-time straining-dominant mono-sized suspension injection is proposed. The aim is avoiding using multiple-size particle suspensions in short-term challenge tests. We derive an exact solution for long-time non-linear injection of particles with the same size, where the non-linearity is determined by accumulation of strained particles and alternation of porous medium properties. The exact downscaling procedure, determining the evolution of pore size distribution from an exact solution of large-scale equations is developed. It shows the preferential plugging of large pores during mono-sized particle transport, explaining well-posed formulation of pore-size distribution tuning from breakthrough concentrations and retention profiles. The laboratory tests on long-term mono-sized injections, where straining dominance has been monitored by DLVO-repulsion between particles and porous media, have been performed. High quality match of the breakthrough concentrations by the analytical model has been observed. The tuned-model-based prediction of the retained profiles also shows close agreement with the experimental data, which validates the proposed method.

Properties of Gadolinium-doped Ceria (GDC) Films Deposited by Reactive Magnetron Sputtering Processes

Reactive magnetron sputtering deposition technique was used for formation of gadolinium doped ceria oxide (GDC) thin films 5- 10µm. Material characteristics and chemical compositions of GDC films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and 3D profilometry. In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness is studied. The GDC thin films were deposited on porous NiO–GDC (nickel oxide–Gadolinium stabilized ceria), the pre-sintered anode green tape were coated with a GDC electrolyte film by reactive magnetron sputtering using PEM (Plasma Emission Monitoring). An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD, SEM and 3D profilometry as deposited and after different annealing treatments. The obtained half-cell, 28 mm of diameter, anode supported solid oxide fuel cell, the porous and density of Ni-GDC10 composite anodes have been elaborated by tape casting method. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. The microstructural morphological /porosity/surface features of the half-cell were analyzed by Scanning Electron Microscopy (SEM), XRD and 3D profilometry before and after different annealing treatment. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method. Finally, the EIS (Electrochemical Impedance Spectroscopy) measurements were done on Ni-GDC10/GDC10 half-cells under 60 sccm nitrogen by the means of a Solartron SI 1260 impedance / gain analyser from 20 MHz to 0.1 Hz with 11 points per decade.

Properties of Gadolinium-doped Ceria (GDC) Films Deposited by Reactive Magnetron Sputtering Processes

Reactive magnetron sputtering deposition technique was used for formation of gadolinium doped ceria oxide (GDC) thin films 5- 10µm. Material characteristics and chemical compositions of GDC films were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness is studied. The GDC thin films were deposited on porous NiO–GDC (nickel oxide–Gadolinium stabilized ceria), the pre-sintered anode green tape were coated with a GDC electrolyte film by reactive magnetron sputtering using PEM (Plasma Emission Monitoring). An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD and SEM as deposited and after different annealing treatments. The obtained half-cell, 28 mm of diameter, anode supported solid oxide fuel cell, the porous and density of Ni-GDC10 composite anodes have been elaborated by tape casting method. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. Finally, Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method.

Fabrication and Characterization of Ni-GDC/GDC Half-Cell Manufactured By Tape Casting and Reactive Magnetron Sputtering Processes As Half-Cell for SOFC

In this work, anode-supported solid oxide fuel cells (SOFCs) has been manufactured by tape casting and co-sintering technique. NiO and GDC (10% Gd), used for the anode-supported (as) and the anode functional layer (afl) powders, with an initial size of -40 mesh and -100 mesh particle size respectively, were milled by using zirconia balls in a Turbula-(System Schatz from WAB) times up to 24 to 48 hours. Half-cell, 28 mm of diameter, Ni-GDC10 composite anodes have been elaborated by slurry based tape casting method for anode supported solid oxide fuel cell. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. The microstructural morphological /porosity/surface features of the half-cell were analyzed by Scanning Electron Microscopy (SEM), XRD and 3D profilometry before and after different annealing treatment. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method. Depending on the results, work on the support anode (AS) Ni-GDC will continue in particular to avoid the presence of the residual phase of carbon resulting from the use of an agent poro formers with graphite. The obtained cell after sintering was seen without any deformation or crack. One of the ways followed to remove the residual graphite is increase of the temperature and / or sintering time.The pre-sintered anode green tape was coated with a GDC electrolyte film by reactive magnetron sputtering using PEM techniques. An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD, SEM and 3D profilometry as deposited and after different annealing treatments. Finally, the EIS measurements were performed on Ni-GDC/GDC half-cells under 60 sccm nitrogen by the means of a Solartron SI 1260 impedance / gain analyzer from 20 MHz to 0.1 Hz with 11 points per decade.

Determination of pore size distributions of virus filtration membranes using gold nanoparticles and their correlation with virus retention

Virus filtration membranes contribute substantially to the virus safety of biopharmaceutical drugs due to their capability to retain viral particles mainly based on the size-exclusion mechanisms. In this work, virus filtration membranes were challenged with gold nanoparticles (GNPs) in order to determine pore size distributions (PSDs) for a wide range of different commercial and non-commercial parvovirus retentive membranes differing in structure, material and surface chemistry. The retention mechanism of GNPs was investigated and effectively shifted towards size-exclusion by using an anionic surfactant to suppress particle adsorption to the membrane surface. This allowed insights into the relevance of particle retention based on size-exclusion mechanisms of the respective membranes. Membrane PSDs investigated through GNP challenges were for some membranes compared with PSDs investigated by liquid-liquid displacement porometry (LLDP). In addition, virus retention performance using Pseudomonas aeruginosa bacteriophage PP7 as accepted model virus was determined for the entire set of membranes and correlated with the cut-off pore size obtained from experiments using GNPs. Exemplarily, retention was examined for one membrane type using a set of different sized viruses or phages (PCV-2, PP7, MVM, HAV) ranging from 18 to 28nm and compared to GNP retention.

Snare Proteins Entropically Expand Membrane Fusion Pores

Neurotransmitters and hormones are released through fusion pores whose dynamics are a critical determinant of the release amount and rate. Fusion pores may flicker repeatedly, before resealing (“kiss & run” fusion) or dilating irreversibly (full fusion). These dynamics are physiologically regulated, but the mechanisms are not understood. Prior studies either monitored single exocytotic pores in live cells with uncontrolled biochemistry, or used in vitro reconstitutions lacking single pore sensitivity. The unavailability of key parameters has hampered development of meaningful models to describe pore dynamics.Here we combine mathematical modeling and single pore measurements to investigate regulation of pore dilation. Experimentally, we measured individual pore conductances with controlled SNARE copy number for the first time. Reconstituting v-SNAREs into ∼23 nm diameter nanolipoprotein particles (discs), we fused discs with patch-clamped cells expressing complementary t-SNAREs and measured currents.We found that SNARE numbers dramatically affected pore size. Just ∼2 SNAREs nucleated pores, but with increasing numbers of SNAREs pores became progressively more dilated. We determined pore size distributions and free energy versus pore size.We developed a coarse-grained mathematical model that reproduced the experimental free energy profiles. Free energies were averaged over fusion pore shapes and configurations of SNARE complexes which could zipper at the pore waist or roam unzippered. Protein-free pores resisted expansion with force ∼19 pN due to membrane tension and bending, close to the experimental value. With SNAREs, zippering drove SNARE assembly at the pore, where SNARE crowding generated entropic pore expansion forces, since bigger pores gave zippered SNAREs more entropy. With 15 SNAREs the entropic expansion force of 14 pN was close to the 19 pN resistance.Our results suggest that SNAREs critically regulate pores post-fusion by entropic expansion forces. Several SNAREs are required to fully dilate pores for efficient contents release.

Suppression of gold nanoparticle agglomeration and its separation via nylon membranes

Abstract Use of ultraporous nylon membrane is one of the most widely employed techniques for removal of hard and soft nanoparticles in the semiconductor industry, and the accurate determination of membrane pore size is necessary in order to avoid manufacturing defects caused by contamination. The gold nanoparticle has several benefits for the evaluation of polymeric membranes; however, the nanoparticles agglomerate easily on the nylon membrane and make it difficult to evaluate the membrane precisely. The properties of 2-amino-2-hydroxymethyl-1,3-propanediol (ADP) ligand in gold nanoparticle solution were systematically investigated, and ADP was utilized for improved evaluation of the nylon membranes. Nylon membrane used in this study was prepared by phase inversion techniques. Ultrathin dense layer on top of the membrane surface and Darcy structures in the microporous membrane support were observed. The gold particle rejection was carried out at various pH values from 4 to 14 and higher rejection was observed at pH 4 and 8. The suppression of gold colloid agglomeration using ADP and monodispersity of gold colloids was also analyzed by confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). van der Waals interaction energy of the particles was reduced in the addition of ADP. The presence of ADP ligand in the gold solutions prevented the agglomeration of gold nanoparticles and reduced the adsorption of the particles on the nylon membrane surface, leading to precise evaluation of membrane pore sizes.

Determination of pore size distribution profile along wellbore: using repeat formation tester

Permeability and porosity are essential properties of hydrocarbon reservoirs that are series to compute the production rates and the original hydrocarbon in-place. Permeability and porosity are often specified by the pore size distribution. Knowing pore size distribution along wellbore can greatly help us in determining perforating depth, mud, and cement type, etc. There are several experimental methods for determining pore size distribution such as capillary pressure measurements, but these methods are time and cost consuming. The goal of this study is to analyze repeat formation tester (RFT) data to determine pore size distribution profile along wellbore. By analyzing RFT data, reservoir pressure, fluids density, fluids contact, and capillary pressure were determined. Pore radiuses were calculated from capillary pressure, and pore size distribution was determined from frequency analysis of pore radius. On the other hand, mercury injection experiments were carried out on several core samples, and the results were used to determine pore size distribution from core analysis. At the last step, the pore size distribution obtained from RFT and core analyses was compared. Result of comparison shows acceptable accuracy of RFT pore size distribution.

Determination of Pore Size, Porosity and Pore Size Distribution of Woven Structures by Image Analysis Techniques

Due to the complexity of fabric structure, modeling of pore structure and predicting the pore parameters are difficult. This paper presents a novel approach to determine textile pore size, porosity and pore size distribution by the application of the image analysis techniques. In this study, it has been attempted to establish a theoretical model for both the pore size and porosity of woven fabrics. For this purpose, a theoretical model of porous systems based on Poiseuille's law was used to predict the pore size of woven fabrics. Also a theoretical model was created to predict the porosity of a woven fabric depending on the geometrical parameters. The two characteristics of pore opening size and porosity were determined from image analysis and were compared to the results from laboratory tests. The validity of which was confirmed by experimental results using cotton plain woven fabrics produced from different yarn linear density and tightness. A new and accurate method of image analysis for pore size distribution (PSD) determination of woven fabrics is presented in this paper. The tested fabric sample could be ranked in a decrease order successfully.

Modification of Microelectrode Surface with Hydrogel Layers and Determination of Pore Size in Layers

Hydrogels are three dimensional networks filled with water. Some of the gels can undergo fast, reversible volume phase transition (VPT) in response to a change in environmental conditions. During the transition the gels transform from one state to another (swollen/ shrunken) by changing content of water in the network. Interestingly, the gels have properties of both: solids and liquids. In the macroscopic scale the structure of the network is responsible for the mechanical energy storage. In the microscopic scale the gels exhibit the properties of water: their density is similar and diffusion processes occur in the network [1]. Pores and channels of nanometer size are employed to separate the analytes by size and to control their transport. The size of the pores could be easily changed in the hydrogel matrix by involving the shrinking and swelling process especially in the gels with continuous volume phase transition. The main aim of this paper was to develop an electrochemical method of obtaining the NIPA- and NIPA-co-AA hydrogel films on the microelectrode surface without previous surface functionalization. Another aim was to determine the size of pores/channels in NIPA- and NIPA-co-%AA gels and to evaluate porosity of the gels. The hydrogel films were anchored to the microelectrode surface via electrochemically induced free radical polymerization (EIFRP) process with utilizing the chronoamperometric method. We found that cyclic voltammetry could be also successfully applied to obtain thin hydrogel layers. The electrochemical studies of the discontinuous volume phase transition and the determination of the channel size were done using the ferrocene molecules modified with polyethylene glycol units (PEG) of various length. Figure 1. Woltamperograms obtained during the electrochemically induced free radical polymerization on platinum microelectrode This work was supported by a grant from the National Science Centre of Poland, Preludium 8, 2014/15/ST5/01980 [1] A. B. Imran, T. Seki, Y. Takeok, Polymer Journal, 2010, 42, 839–851 Figure 1

Molecular Simulation Contribution to Porous Low-k Pore Size Determination after Damage by Etch and Wet Clean Processes - Invited Paper

Porous low-k materials used as insulator for interconnection levels in CMOS devices, are easily damaged during the patterning processes. Pore size characterization after material damage is challenging due to the chemical modification induced by the applied process. Numerical simulation of solvent adsorption on silica and functionalized silica surfaces was used to improve material pore size determination by ellipso-porosimetry, taking into account the modifications of surface/solvent interactions.

Rapid methyl orange degradation using porous ZnO spheres photocatalyst

Porous zinc oxide (ZnO) spheres were synthesized by facile low temperature solution route. The as-synthesized porous ZnO spheres were characterized in detail in terms of their morphological, structural, optical and photocatalytic properties using field-emission scanning electron microscopy (FESEM, equipped with energy dispersive spectroscopy (EDS)), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffractometer (XRD), UV–visible spectroscopy and Raman-scattering measurements. Nitrogen adsorption-desorption analysis was performed to determine pore size distribution from the adsorption isotherm curves using the Barrett-Joyner-Halenda (BJH) method. Morphological and structural characterizations showed porous nature of ZnO spheres with high surface area, good crystallinity, wurtzite hexagonal phase and good optical features. Next, ZnO spheres were studied as photocatalyst for photodegradation of harmful dye, methyl orange (MO). Under ultraviolet light irradiation, the decrease in MO dye concentration was monitored by UV–visible spectroscopy at different time intervals until the dye was completely degraded to colorless end product. Rapid MO dye decomposition was observed with a degradation rate of ~96.3% within the initial 120min, which is attributed to the porous nature, large specific surface area (114.6m2g−1), narrow pore size distribution (~2.5 to 25nm) evaluated from N2 adsorption-desorption isotherms analysis and excellent electron accepting features of the engineered porous ZnO spheres.

A novel method to fabricate porous tricalcium phosphate composite scaffolds for bone tissue engineering applications

This study reports a novel approach for the fabrication of three-dimensional scaffolds using tricalcium phosphate, carboxymethyl cellulose composite with alginate. Microporous (<20 μm) scaffold fibres were made by incorporating gas bubbles within fibres, stabilizing it with surfactants and subsequently removing the gas by vacuum treatment. The morphology of the scaffold was characterized using scanning electron microscopy (SEM). Further, for quantitative determination of pore size, the porosity distribution of the scaffold fibre was determined using mercury intrusion porosimetry (MIP). The volume porosity of these scaffolds was determined by liquid displacement method. Compressive strength, rigidity constant and stiffness index of the constructs were also determined. The in vitro bioactivity studies of these scaffolds were carried out in simulated body fluid (SBF) for 2/4 weeks. This study showed that the scaffold provides a favourable substrate conditions to form a bone-like mineral phase, which might play a significant role in osteointegration.

New insights on estimating pore size distribution of latex particles: Statistical mechanics approach and modeling

New statistical mechanics approach for pore size distribution applied in wide the relative pressure range is proposed. The new proposed model was applied to nitrogen adsorption-desorption isotherms at 77 K onto five functionalized polystyrene latices. Results showed that the proposed model can reproduce all results found by traditional methods such as NLDFT, BJH and VBS where some of them can be applied only for a specific range of pore size. A segmentation procedure is adopted and it is shown that the corresponding algorithm can be successfully applied for determining pore size distributions over a wide range of pore size. When this method is applied an isotherms Type II and III (materials with larger mesopores and/or macropores) gives additional information that is not obtained with the other methods. The obtained results showed that the copolymerization plays an important role in the porosity and the specific surface area, whereas, the high polydispersity index, PDI, can reduce the porosity. The samples studied within the present work present small and large mesopores and even macropores as it is suggested by the new proposed model, and part of this porosity could be related to the interparticle and also to the intraparticle porosity.