Strong aggregation between chains of polyaniline (PANI) emeraldine base (EB) molecules dissolved/... more Strong aggregation between chains of polyaniline (PANI) emeraldine base (EB) molecules dissolved/dispersed in N-methyl-2-pyrrolidinone (NMP) results in a multi-modal molecular weight distribution in gel permeation chromatograph (GPC) results, regardless of how low the concentration of EB is. The addition of a salt, such as lithium chloride (LiCl), is known to improve EB solubility in NMP by deaggregating the polymer chains. However, we have found that ionic liquids, such as 1-methyl-3-butyl imidazolium tetrafluoroborate ([BMIM][BF 4 ]) or 1-methyl-3-ethyl imidazolium tetrafluoroborate ([EMIM][BF 4 ]), not only have less impact on the EB chain conformation than LiCl does, but also deaggregate the EB molecules more effectively. A mono-distributed GPC peak is obtained for EB (M w up to 3 × 10 5 g/mol) dissolved in the NMP/ionic liquid solutions. Therefore, the EB molecular weight distribution is characterized more accurately by using the NMP/ionic liquid solution than the NMP/LiCl solution.
SummaryThermal molecular motion of a series of comb-shaped polymers with heptadecafluorodecyl sid... more SummaryThermal molecular motion of a series of comb-shaped polymers with heptadecafluorodecyl side chains (CF8C2-) has been studied based on dynamic viscoelastic measurement. The main chain of comb-shaped polymers was poly(fumarate), poly(methacrylate), and poly(acrylate). Poly(fluoroalkylfumarate) with heptadecafluorodecyl group, P(CF8C2-iPF) was amorphous polymer, whereas poly(acrylate) and poly(methacrylate) with CF8C2-, P(CF8C2-Acr) and P(CF8C2-MAcr) showed mesomorphic behavior. The pervaporation behavior of water/organic mixtures through amorphous polymer, P(CF8C2-iPF), and mesomorphic one, P(CF8C2-Acr), were investigated. The distinct increase in permselectivity has been observed at the mesomorphic transition of P(CF8C2-Acr).
Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes wi... more Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes without failure (up to 1 million cycles) and fast cycle switching speeds (100 ms). We report results for electrochemical mechanical actuators, electrochromic windows, and numeric displays made from three types of-conjugated polymers: polyaniline, polypyrrole, and polythiophene. Experiments were performed under ambient conditions, yet the polymers showed negligible loss in electroactivity. These performance advantages were obtained by using environmentally stable, room-temperature ionic liquids composed of 1-butyl-3-methyl imidazolium cations together with anions such as tetrafluoroborate or hexafluorophosphate.
Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of... more Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of proteins extracted from mouse tumors 1,2. To allow commercialization of hESC-derived therapeutic cells, culture methods are required that are robust and scalable and that use chemically defined, xeno-free materials. Corning Synthemax Surface is a novel synthetic surface that permits consistent long-term self-renewal of multiple hESC lines in defined, xeno-free media and differentiation of cells to functional cardiomyocytes 3 .
An integrated fermentation and membranebased recovery (pervaporation) process has certain economi... more An integrated fermentation and membranebased recovery (pervaporation) process has certain economical advantages in continuous conversion of biomass into alcohols. This article presents new pervaporation data obtained for poly[1-(trimethylsilyl)-1-propyne] (PTMSP) samples synthesized in various conditions. Three different catalytic systems, TaCl 5 /n-BuLi, TaCl 5 /Al(i-Bu) 3 , and NbCl 5 were used for synthesis of the polymers. It was found that the catalytic system has a significant influence over the properties of membranes made from PTMSP. Although a combination of a high permeation rate and a high ethanolwater separation factor (not less than 15) was provided by all PTMSP samples, the PTMSP samples synthesized with TaCl 5 /n-BuLi showed significant deterioration of membrane properties when acetic acid was present in the feed. In contrast, the PTMSP samples synthesized with TaCl 5 /Al(i-Bu) 3 or NbCl 5 showed stable performance in the presence of acetic acid. When using a multicomponent mixture of organics and water, the copermeation of different organic components results in lower separation factor for both ethanol and butanol. These data are consistent with nanoporous morphology of PTMSP. It was demonstrated that pervaporative removal of ethanol improved the overall performance of the fermentation process.
The pervaporation recovery of ethanol from yeast fermentation broth was investigated using poly[1... more The pervaporation recovery of ethanol from yeast fermentation broth was investigated using poly[1-(trimethylsilyl)-1propyne]. The deterioration of membrane performance in the presence of fermentation broth was observed. The fouled membrane was characterized by gas permeation and density measurements, and sorption of pure components of the fermentation broth in PTMSP was studied to clarify the fouling mechanism. It was concluded that properties of the membrane deteriorate due to internal contamination of the PTMSP free volume with non-volatile by-products of the fermentation. The PTMSP film did not show appreciable deterioration of membrane properties in the pervaporation of aqueous solution of organic compounds with high volatility.
Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) dense films were evaluated for n-butanol recovery from... more Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) dense films were evaluated for n-butanol recovery from aqueous solutions and acetone–butanol–ethanol (ABE) fermentation broth. Flux decline through PTMSP dense films due to polymer compaction under vacuum conditions, relaxation in alcohol and alcohol/water mixtures, and membrane contamination are discussed.Flux decline of a PTMSP film during pervaporation of 20g/l BuOH/water mixture was fitted to the following function, y=At−b. PTMSP
Poly(1-trimethylsilyl-1-propyne) (PTMSP) was synthesized using a TaCl 5-Al(i-Bu) 3 catalysis syst... more Poly(1-trimethylsilyl-1-propyne) (PTMSP) was synthesized using a TaCl 5-Al(i-Bu) 3 catalysis system. Pervaporation and sorption of n-butanol-water mixtures were studied, and the peculiarities of water and butanol co-permeation are discussed. The strong dependence of water partial flux (with a minimum at 1 wt.% butanol in feed) on butanol concentration in feed was observed. S-shaped isotherms of butanol and total sorption were found for PTMSP in 0-1 wt.% concentration range. It appears that blocking of PTMSP nanopores by high sorbing organic molecules controls the pervaporation of butanol from dilute aqueous solutions. Data are discussed in regard with PTMSP morphology.
Synthetic Surfaces for Human Embryonic Stem Cell Culture 91 extractables, particulates, and other... more Synthetic Surfaces for Human Embryonic Stem Cell Culture 91 extractables, particulates, and other contaminants, compatibility with conventional sterilization techniques (typically gamma irradiation), stability at room temperature, similarity to common tissue culture treated (TCT) polystyrene and other cell culture surfaces, and, ideally, the surface needs to be ready for use, rather than require further preparation and manipulation.
Cette invention concerne des surfaces copolymeres de polyolefines cycliques traitees au plasma pr... more Cette invention concerne des surfaces copolymeres de polyolefines cycliques traitees au plasma presentant une densite de liaison amelioree pour lier des cellules et des agents ayant une activite biologique. Ces surfaces peuvent egalement etre ameliorees pour permettre la liaison de cellules et d'agents presentant une activite biologique grâce a l'application de conjugues. L'invention concerne egalement des procedes consistant a fabriquer et a caracteriser des surfaces polymeres traitees.
Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of... more Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of proteins extracted from mouse tumors 1,2. To allow commercialization of hESC-derived therapeutic cells, culture methods are required that are robust and scalable and that use chemically defined, xeno-free materials. Corning Synthemax Surface is a novel synthetic surface that permits consistent long-term self-renewal of multiple hESC lines in defined, xeno-free media and differentiation of cells to functional cardiomyocytes 3 .
Strong aggregation between chains of polyaniline (PANI) emeraldine base (EB) molecules dissolved/... more Strong aggregation between chains of polyaniline (PANI) emeraldine base (EB) molecules dissolved/dispersed in N-methyl-2-pyrrolidinone (NMP) results in a multi-modal molecular weight distribution in gel permeation chromatograph (GPC) results, regardless of how low the concentration of EB is. The addition of a salt, such as lithium chloride (LiCl), is known to improve EB solubility in NMP by deaggregating the polymer chains. However, we have found that ionic liquids, such as 1-methyl-3-butyl imidazolium tetrafluoroborate ([BMIM][BF 4 ]) or 1-methyl-3-ethyl imidazolium tetrafluoroborate ([EMIM][BF 4 ]), not only have less impact on the EB chain conformation than LiCl does, but also deaggregate the EB molecules more effectively. A mono-distributed GPC peak is obtained for EB (M w up to 3 × 10 5 g/mol) dissolved in the NMP/ionic liquid solutions. Therefore, the EB molecular weight distribution is characterized more accurately by using the NMP/ionic liquid solution than the NMP/LiCl solution.
SummaryThermal molecular motion of a series of comb-shaped polymers with heptadecafluorodecyl sid... more SummaryThermal molecular motion of a series of comb-shaped polymers with heptadecafluorodecyl side chains (CF8C2-) has been studied based on dynamic viscoelastic measurement. The main chain of comb-shaped polymers was poly(fumarate), poly(methacrylate), and poly(acrylate). Poly(fluoroalkylfumarate) with heptadecafluorodecyl group, P(CF8C2-iPF) was amorphous polymer, whereas poly(acrylate) and poly(methacrylate) with CF8C2-, P(CF8C2-Acr) and P(CF8C2-MAcr) showed mesomorphic behavior. The pervaporation behavior of water/organic mixtures through amorphous polymer, P(CF8C2-iPF), and mesomorphic one, P(CF8C2-Acr), were investigated. The distinct increase in permselectivity has been observed at the mesomorphic transition of P(CF8C2-Acr).
Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes wi... more Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes without failure (up to 1 million cycles) and fast cycle switching speeds (100 ms). We report results for electrochemical mechanical actuators, electrochromic windows, and numeric displays made from three types of-conjugated polymers: polyaniline, polypyrrole, and polythiophene. Experiments were performed under ambient conditions, yet the polymers showed negligible loss in electroactivity. These performance advantages were obtained by using environmentally stable, room-temperature ionic liquids composed of 1-butyl-3-methyl imidazolium cations together with anions such as tetrafluoroborate or hexafluorophosphate.
Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of... more Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of proteins extracted from mouse tumors 1,2. To allow commercialization of hESC-derived therapeutic cells, culture methods are required that are robust and scalable and that use chemically defined, xeno-free materials. Corning Synthemax Surface is a novel synthetic surface that permits consistent long-term self-renewal of multiple hESC lines in defined, xeno-free media and differentiation of cells to functional cardiomyocytes 3 .
An integrated fermentation and membranebased recovery (pervaporation) process has certain economi... more An integrated fermentation and membranebased recovery (pervaporation) process has certain economical advantages in continuous conversion of biomass into alcohols. This article presents new pervaporation data obtained for poly[1-(trimethylsilyl)-1-propyne] (PTMSP) samples synthesized in various conditions. Three different catalytic systems, TaCl 5 /n-BuLi, TaCl 5 /Al(i-Bu) 3 , and NbCl 5 were used for synthesis of the polymers. It was found that the catalytic system has a significant influence over the properties of membranes made from PTMSP. Although a combination of a high permeation rate and a high ethanolwater separation factor (not less than 15) was provided by all PTMSP samples, the PTMSP samples synthesized with TaCl 5 /n-BuLi showed significant deterioration of membrane properties when acetic acid was present in the feed. In contrast, the PTMSP samples synthesized with TaCl 5 /Al(i-Bu) 3 or NbCl 5 showed stable performance in the presence of acetic acid. When using a multicomponent mixture of organics and water, the copermeation of different organic components results in lower separation factor for both ethanol and butanol. These data are consistent with nanoporous morphology of PTMSP. It was demonstrated that pervaporative removal of ethanol improved the overall performance of the fermentation process.
The pervaporation recovery of ethanol from yeast fermentation broth was investigated using poly[1... more The pervaporation recovery of ethanol from yeast fermentation broth was investigated using poly[1-(trimethylsilyl)-1propyne]. The deterioration of membrane performance in the presence of fermentation broth was observed. The fouled membrane was characterized by gas permeation and density measurements, and sorption of pure components of the fermentation broth in PTMSP was studied to clarify the fouling mechanism. It was concluded that properties of the membrane deteriorate due to internal contamination of the PTMSP free volume with non-volatile by-products of the fermentation. The PTMSP film did not show appreciable deterioration of membrane properties in the pervaporation of aqueous solution of organic compounds with high volatility.
Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) dense films were evaluated for n-butanol recovery from... more Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) dense films were evaluated for n-butanol recovery from aqueous solutions and acetone–butanol–ethanol (ABE) fermentation broth. Flux decline through PTMSP dense films due to polymer compaction under vacuum conditions, relaxation in alcohol and alcohol/water mixtures, and membrane contamination are discussed.Flux decline of a PTMSP film during pervaporation of 20g/l BuOH/water mixture was fitted to the following function, y=At−b. PTMSP
Poly(1-trimethylsilyl-1-propyne) (PTMSP) was synthesized using a TaCl 5-Al(i-Bu) 3 catalysis syst... more Poly(1-trimethylsilyl-1-propyne) (PTMSP) was synthesized using a TaCl 5-Al(i-Bu) 3 catalysis system. Pervaporation and sorption of n-butanol-water mixtures were studied, and the peculiarities of water and butanol co-permeation are discussed. The strong dependence of water partial flux (with a minimum at 1 wt.% butanol in feed) on butanol concentration in feed was observed. S-shaped isotherms of butanol and total sorption were found for PTMSP in 0-1 wt.% concentration range. It appears that blocking of PTMSP nanopores by high sorbing organic molecules controls the pervaporation of butanol from dilute aqueous solutions. Data are discussed in regard with PTMSP morphology.
Synthetic Surfaces for Human Embryonic Stem Cell Culture 91 extractables, particulates, and other... more Synthetic Surfaces for Human Embryonic Stem Cell Culture 91 extractables, particulates, and other contaminants, compatibility with conventional sterilization techniques (typically gamma irradiation), stability at room temperature, similarity to common tissue culture treated (TCT) polystyrene and other cell culture surfaces, and, ideally, the surface needs to be ready for use, rather than require further preparation and manipulation.
Cette invention concerne des surfaces copolymeres de polyolefines cycliques traitees au plasma pr... more Cette invention concerne des surfaces copolymeres de polyolefines cycliques traitees au plasma presentant une densite de liaison amelioree pour lier des cellules et des agents ayant une activite biologique. Ces surfaces peuvent egalement etre ameliorees pour permettre la liaison de cellules et d'agents presentant une activite biologique grâce a l'application de conjugues. L'invention concerne egalement des procedes consistant a fabriquer et a caracteriser des surfaces polymeres traitees.
Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of... more Currently, human embryonic stem cells (hESCs) are cultured on feeder cells or complex mixtures of proteins extracted from mouse tumors 1,2. To allow commercialization of hESC-derived therapeutic cells, culture methods are required that are robust and scalable and that use chemically defined, xeno-free materials. Corning Synthemax Surface is a novel synthetic surface that permits consistent long-term self-renewal of multiple hESC lines in defined, xeno-free media and differentiation of cells to functional cardiomyocytes 3 .
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Papers by Andrei Fadeev