The relationship between heterogeneous structures and phase separation in synthesis of uniform PolyDVB microspheres

In this article, the morphologies of membranes formed by three different systems, i.e. favorable diluent/unfavorable diluent/PVDF system, water-soluble solvent/ unfavorable diluent/PVDF system, and favorable diluent/unfavorable diluent/water-soluble polymer/PVDF system, were characterized, and the relationship between porous membrane morphology and the components of favorable diluent/unfavorable diluent and water-soluble solvent/unfavorable diluent in the system was investigated. The transformation from mesopores to bicontinuous porous structures, from finger-shaped pores to bicontinuous porous structures was realized, and meanwhile PVDF microporous membranes with microfiber-shaped porous structures were manufactured.

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Killing by Type VI secretion drives clonal phase separation and the evolution of cooperation

10.1101/063487 ◽

2016 ◽

Author(s):

Luke McNally ◽

Eryn Bernardy ◽

Jacob Thomas ◽

Arben Kalziqi ◽

Jennifer Pentz ◽

...

Keyword(s):

Phase Separation ◽

Public Goods ◽

Universality Class ◽

Evolution Of Cooperation ◽

Type Vi Secretion System ◽

Secretion Systems ◽

Self Organized ◽

Type Vi Secretion ◽

Solid Media ◽

The Relationship

SummaryBy nature of their small size, dense growth and frequent need for extracellular metabolism, microbes face persistent public goods dilemmas1–5. Spatial assortment can act as a general solution to social conflict by allowing extracellular goods to be utilized preferentially by productive genotypes1,6,7. Established mechanisms that generate microbial assortment depend on the availability of free space8–14; however, microbes often live in densely-packed environments, wherein these mechanisms are ineffective. Here, we describe a novel class of self-organized pattern formation that facilitates the development of spatial structure within densely-packed bacterial colonies. Contact-mediated killing through the Type VI secretion system (T6SS) drives high levels of assortment by precipitating phase separation, even in initially well-mixed populations that do not necessarily exhibit net growth. We examine these dynamics using three different classes of mathematical models and experiments with mutually antagonistic strains of Vibrio cholerae growing on solid media, and find that all appear to de-mix via the same ‘Model A’ universality class of order-disorder transition. We mathematically demonstrate that contact killing should favour the evolution of public goods cooperation, and empirically examine the relationship between T6SSs and potential cooperation through phylogenetic analysis. Across 26 genera of Proteobacteria and Bacteroidetes, the proportion of a strain’s genome that codes for potentially-exploitable secreted proteins increases significantly with boththe number of Type 6 secretion systems and the number of T6SS effectors that it possesses. This work demonstrates how antagonistic traits—likely evolved for the purpose of killing competitors—can indirectlylead to the evolution of cooperation by driving genetic phase separation.

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Effect of the molecular weight and its distribution of polyvinylidene fluoride on the relationship between the spinning process, microstructure and properties of hollow fiber membranes via thermally induced phase separation

Textile Research Journal ◽

10.1177/0040517518770675 ◽

2018 ◽

Vol 89 (7) ◽

pp. 1311-1320 ◽

Cited By ~ 2

Author(s):

Nana Li ◽

Zhe Chang ◽

Qingchen Lu ◽

Changfa Xiao ◽

Junyi Wu ◽

...

Keyword(s):

Molecular Weight ◽

Phase Separation ◽

Polyvinylidene Fluoride ◽

Crystallization Behavior ◽

Water Flux ◽

Thermally Induced Phase Separation ◽

Thermally Induced ◽

Molecular Weights ◽

Spinning Process ◽

The Relationship

Polyvinylidene fluoride (PVDF) is an important material in the preparation of ultrafiltration membranes via the thermally induced phase separation (TIPS) method. In this paper, four PVDF hollow fiber membranes with different molecular weights were prepared via the TIPS method by using dibutyl phthalate and dioctyl phthalate as a mixed diluent. The relationship between the molecular weight of PVDF and its distribution, phase separation, crystallization behavior and spinning process has been systematically studied. The effects of three factors on the microstructure and properties of the PVDF membrane have been analyzed. The flow behaviors of the PVDF/diluent and PVDF melt were tested by a capillary rheometer and a melt flow rate instrument, respectively. A phase diagram of the membrane solution was determined by thermal polarizing microscope and differential scanning calorimetry. The crystallization behavior and angle of orientation of the membrane were tested by using a differential scanning calorimeter and a sound velocity orientation measurement instrument. The microstructures, such as the pore structure and crystalline grain structure, were observed by field emission scanning electron microscopy. Meanwhile, the properties of the membrane were examined from the view of water flux, porosity and tensile testing. The results showed that changes in the polymer molecular weights affected not only the dynamics but also the thermodynamics of phase separation in membrane formation. As the PVDF molecular weight increased, the phase separation region increased, but the membrane structure became denser. A wide molecular weight distribution easily produced large pores. Then, the water flux decreased first and then increased.

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Tailoring PES membrane morphology and properties via selected preparation parameters

Journal of Polymer Engineering ◽

10.1515/polyeng-2015-0419 ◽

2017 ◽

Vol 37 (1) ◽

pp. 69-81 ◽

Cited By ~ 6

Author(s):

Lassaad Gzara ◽

Zulfiqar Ahmad Rehan ◽

Silvia Simone ◽

Francesco Galiano ◽

Naser Tavajohi Hassankiadeh ◽

...

Keyword(s):

Phase Separation ◽

Polyvinyl Pyrrolidone ◽

Preparation Conditions ◽

Membrane Morphology ◽

Flat Sheet ◽

Pes Membrane ◽

The Relationship

Abstract Polyethersulfone (PES) is among the most interesting materials for membranes preparation, thanks to its outstanding properties, coupled to compatibility with several additives and the facility to be solubilized in several solvents. In this work, flat sheet membranes were prepared by the non-solvent induced phase separation (NIPS) technique, using PES as polymer and polyvinyl pyrrolidone (PVP, 10 kDa) as additive. Preparation and casting conditions were varied and membranes with tailored morphology and properties were obtained. The main objective was to investigate the relationship between selected preparation conditions and membrane features. This may help to understand how to tailor membrane morphology and properties depending on the desired application.

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Crystallization and Thermal Expansion of MgO-Al2O3-SiO2-TiO2 Glass-Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.1635 ◽

2007 ◽

Vol 280-283 ◽

pp. 1635-1638

Author(s):

Hua Shao ◽

Kai Ming Liang ◽

Feng Zhou ◽

Fei Peng

Keyword(s):

Heat Treatment ◽

Thermal Expansion ◽

Phase Separation ◽

Thermal Expansion Coefficient ◽

Expansion Coefficient ◽

Treatment Condition ◽

Glass Ceramics ◽

Heat Treatment Condition ◽

Crystallization Sequence ◽

The Relationship

Crystallization sequence of MgO-Al2O3-SiO2-TiO2 system glass was investigated by means of DTA, XRD, SEM and EDS. The relationship between crystalline phases, heat treatment methods and thermal expansion coefficient (α) were well discussed. The results have shown that: The glass first underwent extensive phase separation into titanium-rich droplets in a silica-rich matrix, then magnesium aluminotitanate (MAT) initially precipitated in the droplet phases. With the crystallization temperature increased, β-quartzss, sapphirine, α-quartzss and α-cordierite made their appearance successively. The thermal expansion coefficient as a function of the heat treatment condition was studied.

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ORGANOID AND TISSUE PATTERNING THROUGH PHASE SEPARATION: USE OF A VERTEX MODEL TO RELATE DYNAMICS OF PATTERNING TO UNDERLYING BIOPHYSICAL PARAMETERS

10.1101/136366 ◽

2017 ◽

Cited By ~ 3

Author(s):

William Waites ◽

Matteo Cavaliere ◽

Élise Cachat ◽

Vincent Danos ◽

Jamie A. Davies

Keyword(s):

Phase Separation ◽

Laboratory Data ◽

Quantitative Model ◽

Separation Mechanism ◽

Vertex Model ◽

Biophysical Parameters ◽

Observed Behaviour ◽

The 1960S ◽

The Relationship ◽

Phase Separation Mechanism

AbstractExactly a century ago, D’Arcy Thompson set an agenda for understanding tissue development in terms of underlying biophysical, mathematically-tractable mechanisms. One such mechanism, discovered by Steinberg in the 1960s, is adhesion-mediated sorting of cell mixtures into homotypic groups. Interest in this phase separation mechanism has recently surged, partly because of its use to create synthetic biological patterning mechanisms and partly because it has been found to drive events critical to the formation of organoids from stem cells, making the process relevant to biotechnology as well as to basic development. Here, we construct quantitative model of patterning by phase separation, informed by laboratory data, and use it to explore the relationship between degree of adhesive difference and speed, type and extent of resultant patterning. Our results can be used three ways; to predict the outcome of mix-ing cells with known properties, to estimate the properties required to make some designed organoid system, or to estimate underlying cellular properties from observed behaviour.

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Mechanisms for Conduction Pathway Formation in Polymer Encapsulants

MRS Proceedings ◽

10.1557/proc-154-65 ◽

1989 ◽

Vol 154 ◽

Author(s):

J. E. Anderson ◽

D. A. Hoffmann ◽

C. W. Frank ◽

L. J. Bousse

Keyword(s):

Phase Separation ◽

Liquid Phase ◽

Ionic Conduction ◽

Osmotic Swelling ◽

Polymer Fracture ◽

Heterogeneous Structures ◽

Conduction Pathway ◽

Bulk Polymers ◽

Pathway Formation ◽

Liquid Liquid Phase Separation

AbstractThis article concerns physicochemical mechanisms leading to formation of local heterogeneous structures in bulk polymers. Previous experimental work suggests that such heterogeneities are related to ionic conduction and electrochemical attack on encapsulated microelectronics. Six mechanisms are discussed: (a) Macrosyneresis; (b) Osmotic swelling; (c) Liquid-liquid phase separation; (d) Microsyneresis; (e) Polymer fracture during solvent sorption/desorption; (f) Polymer-substrate interactions.

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Study on Structure of the New Polymer-Poly (Propylene-Co-γ-Butyrolactone Carbonate) with Molecular Model

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.3076 ◽

2007 ◽

Vol 353-358 ◽

pp. 3076-3079

Author(s):

Ling Bin Lu ◽

Ke Long Huang ◽

Feng Wen

Keyword(s):

Phase Separation ◽

Self Assembly ◽

Molecular Model ◽

The Self ◽

Molecular Chain ◽

Drug Molecule ◽

Carboxylic Ester ◽

Poly Propylene ◽

The Relationship ◽

Materials Studio

Based on COMPASS forcefield, the relationship between microstructure and macroscopic properties of poly (propylene-co-γ-butyrolactone carbonate) (PPCG) was firstly investigated with ‘Materials Studio’ simulation soft successfully. The results of simulation showed that the molecular chain of PPCG was flexible. Degradable carbonic and carboxylic ester groups were distributed outside the PPCG cell. Furthermore the structure of micro-phase separation was observed in PPCG cell. The structure of micro-phase separation of PPCG can be applied to the self-assembly of drug molecule.

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