APTES assisted surface heparinization of polylactide porous membranes for improved hemocompatibility

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42684-42692 ◽  
Author(s):  
Jinglong Li ◽  
Fu Liu ◽  
Xuemin Yu ◽  
Ziyang Wu ◽  
Yunze Wang ◽  
...  
Keyword(s):  
Porous Membrane ◽  
Porous Membranes ◽  
Amidation Reaction

The Hep-APTES/PLA was synthesized through the amidation reaction and results showed that surface heparinization significantly improved the hemocompatibility of PLA porous membrane.

scholarly journals Effect of moisture condensation on vapour transmission through porous membranes

2021 ◽  
pp. 152808372110142
Author(s):  
Ariana Khakpour ◽  
Michael Gibbons ◽  
Sanjeev Chandra
Keyword(s):  
Water Vapour ◽  
Moisture Diffusion ◽  
Porous Membrane ◽  
Water Evaporation ◽  
Porous Membranes ◽  
Water Vapour Concentration ◽  
Vapour Concentration ◽  
Vapour Diffusion ◽  
Pore Blockage ◽  
The Impact

Porous membranes find natural application in various fields and industries. Water condensation on membranes can block pores, reduce vapour transmissibility, and diminish the porous membranes' performance. This research investigates the rate of water vapour transmission through microporous nylon and nanofibrous Gore-Tex membranes. Testing consisted of placing the membrane at the intersection of two chambers with varied initial humidity conditions. One compartment is initially set to a high ([Formula: see text]water vapour concentration and the other low ([Formula: see text], with changes in humidity recorded as a function of time. The impact of pore blockage was explored by pre-wetting the membranes with water or interposing glycerine onto the membrane pores before testing. Pore blockage was measured using image analysis for the nylon membrane. The mass flow rate of water vapour ( ṁv) diffusing through a porous membrane is proportional to both its area (A) and the difference in vapour concentration across its two faces ([Formula: see text], such that [Formula: see text] where K is defined as the moisture diffusion coefficient. Correlations are presented for the variation of K as a function of [Formula: see text]. Liquid contamination on the porous membrane has been shown to reduce the moisture diffusion rate through the membrane due to pore blockage and the subsequent reduced open area available for vapour diffusion. Water evaporation from the membrane's surface was observed to add to the mass of vapour diffusing through the membrane. A model was developed to predict the effect of membrane wetting on vapour diffusion and showed good agreement with experimental data.

Porous membranes of quaternized chitosan composited with strontium-based nanobioceramic for periodontal tissue regeneration

2021 ◽  
pp. 088532822110502
Author(s):  
Adarsh Rajeswari Krishnankutty ◽  
Shamna Najeema Sulaiman ◽  
Arun Sadasivan ◽  
Roy Joseph ◽  
Manoj Komath
Keyword(s):  
Tensile Strength ◽  
Tissue Regeneration ◽  
Porous Membrane ◽  
Periodontal Ligament Cells ◽  
Porous Membranes ◽  
Pull Out ◽  
Periodontal Tissue Regeneration ◽  
Phosphate Buffered Saline ◽  
Pull Out Strength

This report demonstrates the development of a degradable quaternary ammonium derivative of chitosan (QC) composited with strontium-containing nanoapatite (SA) for bioactivity. The material was made as porous membrane by solution casting and freeze drying, for guided tissue regeneration (GTR) applications. The micromorphology, tensile strength, suture pull-out strength, degradation ( in vitro, in phosphate buffered saline), and cytocompatibility (using human periodontal ligament cells) were tested to investigate the effect of derivatization and SA addition. The porosity of the membranes increased with increasing SA content and so did the tensile strength and the degradation. The suture pull-out strength, however, showed a decrease. The cell culture evaluation endorsed biocompatibility. The composite with 1.5 mg SA per 1 mL QC was found to have optimal qualities for GTR applications.

Transport of Gases in Porous Membranes

MRS Bulletin ◽  
1999 ◽  
Vol 24 (3) ◽  
pp. 41-45 ◽  
Author(s):  
Stratis V. Sotirchos ◽  
Vasilis N. Burganos
Keyword(s):  
Pore Space ◽  
Chemical Species ◽  
Molecular Size ◽  
Porous Membrane ◽  
Transport Processes ◽  
Porous Membranes ◽  
Gaseous Species ◽  
Interior Space ◽  
Separation Processes ◽  
Membrane Pore

The capability of membranes to affect differently, both qualitatively and quantitatively, the transport rates of chemical species of dissimilar chemical structure through their interior space renders them attractive for use in many separation problems. Extensive research efforts have thus been undertaken on the preparation and characterization of membrane materials and the study of the transport processes involved in their use in separation applications. The study of the transport of gaseous species through the pore space of porous membranes and the analysis and understanding of the mechanisms that are involved in this process are a very important, if not the most important, element in the development of membranebased separation processes.The resistance that a gaseous species encounters as it is transported through the pore space of a porous membrane is a function of its molecular properties, of its interaction with the material that makes up the walls of the pores, and of the membrane pore structure. Gaseous transport in pores can take place through various mechanisms, whose contribution to the overall transport rate of a particular species is, in general, determined by the strength of the interactions of the molecules of that species with the pore walls and by the relative magnitudes of three length scales that characterize the molecular size, the distance between pore walls, and the density of the fluid in the pore space.

Self-Supporting pH-Responsive Micro Porous Membrane from Copolymer PVA-co-PDEAEMA

2013 ◽  
Vol 838-841 ◽  
pp. 2314-2317
Author(s):  
Ping Jiang ◽  
Du Xin Li ◽  
Yun Jun Liu
Keyword(s):  
Optical Microscopy ◽  
Water Flux ◽  
Porous Membrane ◽  
Porous Membranes ◽  
Coating Process ◽  
Ph Responsive ◽  
Membrane Systems ◽  
Polarized Optical Microscopy ◽  
Curtain Coating ◽  
Supporting Membrane

Self-supporting pH-responsive micro porous membranes from Copolymer PVA-co-PDEAEMA were prepared via curtain coating process. The morphologies of the micro porous membranes were investigated by polarized optical microscopy. The above polymers were shown to form self-supporting membrane systems that were able to react on pH stimuli in terms of water flux.

Effect of PVP Hydrophilic Additive on the Morphology and Properties of PVDF Porous Membranes

2014 ◽  
Vol 981 ◽  
pp. 891-894 ◽  
Author(s):  
Yun Wei Guo ◽  
Wei Wei Cui ◽  
Wen Hua Xu ◽  
Yang Jiang ◽  
Hui Hui Liu ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Porous Membrane ◽  
Porous Membranes ◽  
Inversion Method ◽  
Water Contact ◽  
Poly Vinylidene Fluoride ◽  
Pure Water Flux ◽  
Phase Inversion Method

This work describes the preparation and the properties of poly(vinylidene fluoride) (PVDF) porous membranes. The porous membrane was prepared using phase-inversion method by adding hydrophilic polyvinylpyrrolidone (PVP) as hole-agent. The contrastive analysis of membrane characterizations between the membrane no PVP added and the membrane added PVP were carried out by optical microscopy analysis, scanning electron microscopy, porosity, pure water flux and water contact angle. The results showed that adding PVP can induce the building of pore structure, increase the surface roughness and hydrophilicity of PVDF membrane, and then enhance its pure water flux.

scholarly journals A novel nanofiltration membrane inspired by an asymmetric porous membrane for selective fractionation of monovalent anions in electrodialysis

RSC Advances ◽  
2018 ◽  
Vol 8 (53) ◽  
pp. 30502-30511 ◽  
Author(s):  
Jincheng Ding ◽  
Shanshan Yang ◽  
Jiefeng Pan ◽  
Yu Zheng ◽  
Arcadio Sotto ◽  
...  
Keyword(s):  
Membrane Separation ◽  
Porous Membrane ◽  
Porous Membranes ◽  
Nanofiltration Membrane ◽  
Nanofiltration Membranes ◽  
Monovalent Anion ◽  
Selective Membranes

The present study describes the synthesis of new nanofiltration membranes inspired by asymmetric porous membranes used as monovalent anion selective membranes for electro-membrane separation.

scholarly journals The Beauty and Mystery of the Micro World

2019 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Porous Membrane ◽  
Electrolyte Composition ◽  
Self Organization ◽  
Porous Membranes ◽  
Pulsed Current ◽  
Scientific Journals ◽  
Experimental Conditions ◽  
Current Pulses ◽  
Natural Objects ◽  
Electric Current Pulses

The beauty of these pictures is intriguing and fascinating by its asymmetric, exquisite and intricate patterns. What is it? Is it a product of a novel computer program or photographs of fine creations of nature? Neither of the statements is true. In fact, these are not art pictures, but real images of metal samples made with an electron microscope. Only some colours are added to the images to emphasize their resemblance to natural objects of our world: mushrooms, leaves of exotic plants, and seashells. The size of the samples is from tens of microns to 1-2 millimeters. They are produced via self-organization of nano-sized (1/million of a millimeter) wires growing on porous membranes under the action of electric current pulses. We have described comprehensively these volumetric (3D) sculptures as well as the experimental conditions for their fabrication in scientific journals [1- 5]. The most important parameters of the fabrication process (electrolyte composition, porous membrane, pulsed current modes) are specified, indicating when growing nanowires organize themselves in an inexplicable fashion into “sculptures” that show perfect resemblance to natural objects.

scholarly journals Study on Preparation and Separation and Adsorption Performance of Knitted Tube Composite β-Cyclodextrin/Chitosan Porous Membrane

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1737 ◽  
Author(s):  
Qian Tang ◽  
Nana Li ◽  
Qingchen Lu ◽  
Xue Wang ◽  
Yaotian Zhu
Keyword(s):  
Contact Angle ◽  
Water Flux ◽  
Crosslinking Agent ◽  
Composite Membranes ◽  
Rejection Rate ◽  
Porous Membrane ◽  
Porous Membranes ◽  
Porous Network ◽  
Adsorption Performance ◽  
Elovich Equation

In order to obtain membranes with both organic separation and adsorption functions, knitted tube composite β-cyclodextrin/chitosan (β-CD/CS) porous membranes were prepared by the non-solvent induced phase separation (NIPS) method using CS and β-CD as a membrane-forming matrix, glutaraldehyde as crosslinking agent to improve water stability, and knitted tube as reinforcement to enhance the mechanical properties. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), contact angle, water flux, bovine serum albumin (BSA) rejection and tensile test were carried out. The FTIR demonstrated that the β-CD and CS had been successfully crosslinked. With the crosslinking time increased, the membrane structure became denser, the contact angle and the rejection rate increased, while the water flux decreased. The strength and elongation at a break were 236 and 1.7 times higher than these of bare β-CD/CS porous membranes, respectively. The strength of crosslinking membranes increased further. The adsorption performance of composite membranes was investigated for the removal of phenolphthalein (PP) from aqueous solution. The adsorption process followed the Langmuir isotherm model, and the kinetic behavior was accorded with the Double constant equation and the Elovich equation. The adsorption mechanism could be explained by the synergistic effect of host-guest interaction from β-cyclodextrin, non-uniform diffusion and porous network capture.

Experimental Determination of Pressure Loss Through Porous Membranes

2014 ◽  
Author(s):  
Gary A. Anderson ◽  
Anil Kommareddy ◽  
Zhengrong Gu ◽  
Joanne Puetz Anderson ◽  
Stephen P. Gent
Keyword(s):  
Carbon Dioxide ◽  
Pore Size ◽  
Water Depth ◽  
Air Flow ◽  
Porous Membrane ◽  
Least Square ◽  
Porous Membranes ◽  
Plastic Sheet ◽  
Reactor Volume ◽  
Novel Approach

Air with carbon dioxide is bubbled through Photobioreactors (PBRs) to add carbon dioxide to the reactor medium, remove oxygen, and mix the medium. Most PBR systems use various types of spargers/diffusers that consist of straight or curved tubes with perforation in them to inject air into the PBR reactor volume. A possible novel approach to introducing air into the PBR reactor volume is to use a plenum under the PBR reactor volume in conjunction with a porous membrane that separates the air in the plenum from the liquid medium in the reactor volume. The resistance offered by the porous membrane and the liquid in the reactor volume to air flow needs to be established so that power requirements to provide the desired air flow through the PBR can be determined. Four types of porous membranes were tested: 1)Sintered High Density Polyethylene HDPE 1.59 mm thick with 15–45 μm pore size, 2) Sintered HDPE 0.79 mm thick with 20μm pore size, 3) Genpore black plastic sheet with 45 μm pore size, and 4) Porex 7896 HDPE with pore size of 35 μm). Specimens were tested in a 76.2 mm inside diameter reactor with a depth of 304.8mm and a 76.2 mm plenum depth. Water was used as the reactor medium and the depth was varied between 0 and 228.6 mm. Results showed that the Porex 7896 membrane had little resistance to air flow when the water depth was 0.0mm (1–22 Pa), 1–200 Pa for the Genpore plastic sheet, 1200–1400Pa for the Porex with 20μm pores, and 1100–2500 Pa for the Porex with the 15–45 μm pore sizes for superficial air velocities between 0.00345 m/s to 0.0242 m/s. Water depth was then increased to 228.6 mm in 25.4 mm increments and tested with the same air flow rates. The addition of water significantly increased the resistance to air flow for all membranes (highest being 4200 Pa). Least square correlations for the membranes using water depth and superficial air velocity indicate that resistance to air flow of the membranes was linear with superficial velocity but parabolic with water depth.

scholarly journals A Model for Stokes Flow in Domains with Permeable Boundaries

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 381
Author(s):  
Ricardo Cortez ◽  
Marian Hernandez-Viera ◽  
Owen Richfield
Keyword(s):  
Protein Concentration ◽  
Incompressible Flows ◽  
Concentration Field ◽  
Porous Membrane ◽  
Porous Membranes ◽  
Closed Domain ◽  
Fluid Flux ◽  
Dynamic Changes ◽  
Viscous Incompressible Flows ◽  
Source Sink

We derive a new computational model for the simulation of viscous incompressible flows bounded by a thin, flexible, porous membrane. Our approach is grid-free and models the boundary forces with regularized Stokeslets. The flow across the porous membranes is modeled with regularized source doublets based on the notion that the flux velocity across the boundary can be viewed as the flow induced by a fluid source/sink pair with the sink on the high-pressure side of the boundary and magnitude proportional to the pressure difference across the membrane. Several validation examples are presented that illustrate how to calibrate the parameters in the model. We present an example consisting of flow in a closed domain that loses volume due to the fluid flux across the permeable boundary. We also present applications of the method to flow inside a channel of fixed geometry where sections of the boundary are permeable. The final example is a biological application of flow in a capillary with porous walls and a protein concentration advected and diffused in the fluid. In this case, the protein concentration modifies the pressure in the flow, producing dynamic changes to the flux across the walls. For this example, the proposed method is combined with finite differences for the concentration field.

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