STUDY ON PHASE-SEPARATION OF PMMA/SAN BLENDS INDUCED BY GLASS BEADS THROUGH DYNAMIC RHEOLOGICAL MEASUREMENTS

Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfilled and filled poly（methyl methyacrylate） （PMMA）/poly（styrene-co-acrylonitrile） （SAN） blends were studied in order to explore the effect of GB on the phase-separation of binary polymer matrix. Results show that GB has an induced effect on the phase-separation, which embodies that the phase-separation temperature （Ts） of PMMA/SAN blend filled with GB is lower than that of the unfilled system. The higher content of GB, the higher is the ＂secondary plateau＂ of ω in the terminal region of storage modulus （G＇） versus ω plot. The ＂secondary plateau＂ appearing in the terminal region is attributed to the phase-separation of PMMA/SAN blends and it becomes more fiat for filled polymer blends under the same conditions. However, it is suggested that this kind of ＂induced effect＂ is related to the GB content; the higher content of GB particles might enhance the interaction between the particles and polymer matrix. Moreover, it is found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. It is believed that the plot of dynamic viscosity （η＇） versus the loss viscosity （η＂） is sensitive to examine the effect induced by GB on the phase-separation of binary polymer matrix.

Study on Electromagnetic Transient Condition of EMU Passing by Phase-separation with Electric Load in High-speed Railway

Aiming at the complex electromagnetic transient process of EMU passing by phase-separation with electric load in high-speed railway, mechanism of overvoltage caused by switching off, overvoltage caused by switching on and impact current is analyzed systematically in this article. π-type equivalent circuit of feeding section is put forward in the analysis of overvoltage mechanism. Overvoltage and overcurrent model of passing by phase-separation with electric load are also built. Correctness of mechanism was validated by simulation. In addition, the methods to solve the influence on substations, transformers and protection devices in this process are put forward, which provides a new idea on passing by phase-separation with electric load technology.

Thermoregulated Phase-separable Ru_3(CO)_(12)/PETPP Complex Catalyst for Hydrogenation of Styrene

Thermoregulated phase-separable Ru-3(CO)(12)/PETPP (PETPP=P[p-C6H4O (CH2CH2O)(n) H](3), n=6) complex catalyst was first applied in the hydrogenation of styrene. Under the conditions: P(H-2)=2.0MPa, T=90degreesC, styrene could be completely transferred and the yield of ethylbenzene reached up to 99.5%. After simple decantation, the catalyst could be reused for ten times without decreasing in activity.

Studies on the Recycling Efficiency of Thermoregulated Phase-separable Rh/PETPP Complex Catalyst

Effects on the recycling efficiency of thermoregulated phase-separable Rh/PETPP (P-[p-C6H4O(CH2CH2O)nH]3, N=3n) complex catalyst involved in hydroformylation of 1-decene are for the first time presented. It was found that the loss of Rh is dependent greatly on the composition of phosphine ligand PETPP and the organic solvent employed in the reaction.

INVESTIGATION OF STRUCTURE AND PROPERTIES FOR POLYMER SYSTEMS BASED ON DYNAMIC RHEOLOGICAL APPROACHES

The dynamic rheological measurements have been a preferred approach to the characterization of the structure and properties for multi-component or multi-phase polymer systems,due to its sensitive response to changes of structure for these heterogeneous polymers.In the present article,recent progresses in the studies on dynamic rheology for heterogeneous polymer systems including polymeric composites filled with inorganic particles,thermo-oxidized polyolefins,phase- separated polymeric blends and functional polymers with the scaling and percolation behavior are reviewed,mainly depending on the results by the authors' group.By means of rheological measurements,not only some new fingerprints responsible for the evolution of morphology and structure concerning these polymer systems are obtained,the corresponding results are also significant for the design and preparation of novel polymer-based composites and functional materials.

Compressive Deformation Induced Nanocrystallization of a Supercooled Zr-Based Bulk Metallic Glass

The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, compressive deformation promotes the development of nucleation and suppresses the coarsening of nanocrystallites at high temperatures.

Formation of Pd-Ni Based Bulk Metallic Glasses

Bulk metallic glasses are prepared in Pd4o.sNi4o.sSixP19-x （x = 0-14 at.%） alloys by a combination of flux treatment and water quenching technique. It is found that the thermal stability of the Pd4o.sNi4o.sSixP19=x glassy alloys depends on the addition of Si content. Among the Pd4o.sNi4o.sSixP19=x glassy alloys studied, the Pd4o.sNi4o.sSisPls bulk metallic glass exhibits the largest supercooled liquid region （△T = 119 K） and the highest activation energy of crystallization （283.3k J/tool）, showing enhanced glass formation ability and extraordinary glassy thermal stability.

Simulation of Temperature-Dependent Resistivity for Manganite La1/3Ca2/3MnO3

The resistivity of the heavy-doped La1/3Ca2/3MnO3 （LCMO） is simulated using a random resistor network model, based on a phase separation scenario. The simulated results agree well with the reported experimental data, showing a transition from a charge-disordered （CDO） state embedded with a few ferromagnetic （FM） metallic clusters to a charge-ordered （CO） state, corresponding to the transition from a high-temperature paramagnetic （PM） insulating state to a low-temperature antiferromagnetic （AF） insulating state. Furthermore, we find that the number of AF/CO clusters increases with decreasing temperature, and the clusters start to connect to each other around 250K, which causes percolating in the system. The results further verify that phase separation plays a crucial role in the electrical conductivity of LCMO.

Aggregation Behaviour of Cationic Diblock Copolymer （MTAC）10（BA）16： MesoDyn Simulation Study

The aggregation behaviour of an amphiphilic cationic block copolymer （MTAC）10（BA）16 in aqueous solution is investigated by MesoDyn simulation. Simulation results show that （MTAC）10 （BA）16 can form spherical, irregular and network aggregates with the increasing volume fraction. The time evolution of order parameter shows that the process of aggregate formation can be divided into diffusion control stage and hydrophobic interaction control stage, while the time evolution of energy indicates that the aggregate formation is driven by enthalpy but not entropy. The order parameter of the hydrophobic blocks BA increases with the increasing （MTAC）10（BA）16 concentration, while the time needed for system balance has the contrary trend.

The Dynamics of Acid Treatment in the Preparation of Porous Glass

The phase-separation glasses with composition of Na 2O(9.0)B 2O 3(25.0)-SiO 2(66.0)(in mole ratio)were leached with hydrochloric acid,and porous glasses were prepared.The dynamics of the acid treatment was investigated.The effects of treatment time,temperature and acid concentration on the acid treatment process were studied using HCl as treatment solution.The dynamics equation and apparent activation energy obtained in acid treatment process were dw/dt=a/2t and E=57.74 kJ·mol -1,respectively.The constants of the reaction rate at different temperatures were calculated.On the basis of experimental data the mechanism of acid treatment process and the source of swollen stress,which was the main stress during treatment process,were discussed.

Effect of Thermal Treatment and Acid Leaching Process on Pore Characteristics of Nanometer Porous Glass

Porous glass was prepared by thermally treating sodium borosilicate glass for different time, the effect of thermal treatment on pore size distribution was discussed and the pore size of the prepared porous glass was measured by scanning electron microscopy （SEM） and differential thermal analysis （DTA）. The results show that the optimum porous glass with an average diameter of 80 nm can be prepared by thermal treatment at 600℃ for 12 h and then acid treatment for 12 h in 2 mol·L^-1 hydrochloric acid solution.

Poly(2-acetoxyethyl methacrylate)/polystyrene latex interpenetrating polymer networks with well-defined phase-separated structure

A series of poly（2-acetoxyethyl methacrylate）/polystyrene（PAEMA/PS） latex interpenetrating polymer networks（LIPNs） were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator.These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase.The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.

CRISPR-assisted transcription activation by phaseseparation proteins

The clustered regularly interspaced short palindromic repeats(CRISPR)-Cas9 system has been widely used for genome engineering and transcriptional regulation in many different organisms.Current CRISPR-activation(CRISPRa)platforms often require multiple components because of inefficient transcriptional activation.Here,we fused different phase-separation proteins to dCas9-VPR(dCas9-VP64-P65-RTA)and observed robust increases in transcriptional activation efficiency.Notably,human NUP98(nucleoporin 98)and FUS(fused in sarcoma)IDR domains were best at enhancing dCas9-VPR activity,with dCas9-VPR-FUS IDR(VPRF)outperforming the other CRISPRa systems tested in this study in both activation efficiency and system simplicity.dCas9-VPRF overcomes the target strand bias and widens gRNA designing windows without affecting the off-target effect of dCas9-VPR.These findings demonstrate the feasibility of using phase-separation proteins to assist in the regulation of gene expression and support the broad appeal of the dCas9-VPRF system in basic and clinical applications.

Solution properties and self-association of multi-blocks like copolymer P(AM/AA) prepared by template copolymerization

The association and properties of multi-block like copolymers(TP)of acrylamide(AM)and acrylic acid(AA)prepared by template copolymerization in aqueous solution were studied.The results showed that the copolymers of this type exhibited a significant structure effect compared with that of similar random copolymers(CP)obtained by copoly-merization in the absence of template.Decreasing the value of pH or adding Ca2+ion to the copolymer solution will make phase separation occur.The TEM images demonstrated that the phase separation caused by Ca2+ion was due to the forma-tion of extensively intermolecular cross-linking.With the increase of the pH value of copolymer solution,the changes of the solution viscosity was similar with that of homopoly-acrylic acid,which originally increased and then decreased.But the increase range of template copolymer was higher than that of homopolyacrylic acid.TEM images indicated that at the maximal viscosity the copolymer obtained in the presence of template formed coiled aggregates.

Lattice Boltzmann Models with Mid-Range Interactions

An extension of the standard Shan-Chen model for non ideal-fluids,catering for mid-range,soft-core and hard-core repulsion,is investigated.It is shown that the inclusion of such mid-range interactions does not yield any visible enhancement of the density jump across the dense and light phases.Such an enhancement can however be obtained by tuning the exponents of the effective interaction.The results also indicate that the inclusion of soft-core repulsion can prevent the coalescence of neighborhood bubbles,thereby opening the possibility of tailoring the size of multi-droplet configurations,such as sprays and related phase-separating fluids.

Single Emulsion Microfluidic Production of Janus and Core-Shell Particles via Off-chip Polymerization

In this work, we describe a straightforward approach to produce monodisperse Janus and core-shell particles by using organic solvent free single emulsion droplet-based microfluidic device combining with off-chip polymerization. To accomplish this, methyl methacrylate（MMA） was used as both the oil phase and solvent to dissolve a polymerizable PEGbased macromolecular surfactant, instead of traditional surfactant, and the photo-initiator. Janus particles can be easily obtained by off-chip UV polymerization due to polymerization induced phase separation between PEG and the formed poly（methyl methacrylate）. At the same time, core-shell particles can also be easily attained by inverting the original collecting tube several times and then exposing to UV light. These results may extend the scope of microfluidic technology and the studies on polymerization induced self-assembly/phase-separation into easy fabrication of various new functional materials.

Recent progress on the activation of the cGAS–STING pathway and its regulation by biomolecular condensation

The cyclic guanosine monophosphate (GMP)–adenosine monophosphate (AMP) synthetase (cGAS)–stimulator of interferon genes(STING) pathway, comprising the DNA sensor cGAS, the second messenger cyclic GMP–AMP (cGAMP), and the endoplasmicreticulum (ER) adaptor protein STING, detects cytoplasmic double-stranded DNA (dsDNA) to trigger type I-interferon responses forhost defense against pathogens. Previous studies defined a model for the allosteric activation of cGAS by DNA-binding, but recentwork reveals other layers of mechanisms to regulate cGAS activation such as the phase condensation and metal ions, especially thediscovery of Mn^(2+) as a cGAS activator. Activation of the 23-cGAMP sensor STING requires translocating from the ER to the Golgiapparatus. The sulfated glycosaminoglycans at the Golgi are found to be the second STING ligand promoting STING oligomerizationand activation in addition to 23-cGAMP, while surpassed levels of 23-cGAMP induce ER-located STING to form a highly organizedER membranous condensate named STING phase-separator to restrain STING activation. Here, we summarize recent advances in theregulation of cGAS–STING activation and their implications in physiological or pathological conditions, particularly focusing on theemerging complexity of the regulation.

Mechanically Strong and Highly Stiff Supramolecular Polymer Composites Repairable at Ambient Conditions

It is a formidable challenge to fabricate healable polymeric materials with high mechanical strength and stiffness due to the highly suppressed diffusion of their polymer chains.Herein,a high-strength,highly stiff,andrepairable/healable supramolecular polymercomposite was fabricatedby complexingpoly(acrylic acid)(PAA)and poly(allylamine hydrochloride)(PAH)in aqueous solutions,followed by molding into desired shapes.Exquisitely tuning the electrostatic and H-bonding interactions between PAA and PAH led to associative phase-separation and in situ formation of nanostructures in the resultant PAA–PAH composites.