Propylene Oxide Block Copolymers Research Articles

Study of microvia filling process based on multi-physical coupling

ABSTRACTThe microvia filling process used in the high-density interconnect printed circuit board manufacturing industry was investigated by multi-physical coupling technology. To achieve a perfect filling, SPS (bis-(sodium-sulphopropyl)-disulphide), EO/PO (ethylene oxide and propylene oxide block co-polymers) and PEOPI (polyethylene oxide-polyimide) were used. Furthermore, electrochemical behaviours of electrodeposition were investigated by cyclic voltammetry, galvanostatic potential transient measurement and dynamic potential polarisation technology. Through numerical simulation, the relationship between coverage of additive, concentration of additive, rotating speed of rotating disc electrode, exchange current density and curve slope was fitted. Based on multi-physical coupling to copper electrodeposition, a mathematical model of microvia filling was built to simulate the filling process by a finite element method, and a systematic analysis of the whole filling process was carried out. The void-free microvia filling and filling process with different shapes were finally achieved in acid copper electroplating solutions consisting of 0.3 M CuSO4·5H2O, 0.2 M H2SO4 and 80 mg L−1 Cl− (virgin make-up solution) plus additives SPS, EO/PO and PEOPI. Subsequently, from images of the microvia filling experiment at different times, shape evolution of the microvia filling and variation of electrodeposition rate at the bottom of the microvia and surface were analysed. The modelling result was compared with the measured data and showed good agreement with the experiment. The results showed that a process model was an excellent tool for quickly and cheaply studying the process behaviour greatly reduced need to execute time-consuming and costly experiments.

Synthesis of mesoporous silica material with ultra-large pore sizes and the HDS performance of dibenzothiophene

Ultra-large mesoporous silica materials using different micelle expanders including hexane, cyclohexane, 1,3,5-triisopropylbenzene and 1,3,5-triethylbenzene, have been successfully synthesized by the template of polymer surfactant of P123 (Aldrich, EO20PO70EO20). Among all the used micelle expanders, highly ordered cubic mesoporous silica material (SBA-16@hexane) with ultra-large pore size was obtained by using hexane. All the obtained samples were well characterized by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), nitrogen adsorption–desorption, UV–vis diffuse reflectance spectroscopy (DRS), H2-TPR, pyridine-FTIR, 27Al MAS NMR, GC–MS and Raman. The synthesis mechanism was also proposed. Compared with the conventional SBA-16 (6.31 nm) synthesized taking polymer surfactant of F127 (propylene oxide block copolymer) as the template, the as-synthesized SBA-16@hexane had a pore diameter of 15.1 nm with a highly ordered mesostructure, which was the largest one among all the reported pore sizes of SBA-16 materials. The corresponding hydrodesulfurization (HDS) catalysts of NiMo/Al-SBA-16@hexane, NiMo/γ-Al2O3, and NiMo/Al-SBA-16 were prepared by using different supports respectively, furthermore, their HDS performances were evaluated adopting dibenzothiophene (DBT) as the probe reactant. The DBT HDS efficiencies over these catalysts followed the order: NiMo/Al-SBA-16@hexane > NiMo/γ-Al2O3 > NiMo/Al-SBA-16. The high activity of NiMo/Al-SBA-16@hexane can be attributed to the superior diffusivity of the novel support of SBA-16@hexane with ultra-large pore size.

Поверхностно-активные свойства композиционных систем на основе синтетических полиэлектролитов и неионных ПАВ в условиях засоленности среды

For intensification of the imbibition process of porous systems and for displacing liquids by other liquids, particularly in secondary oil production, the polycomplexes based on synthetic polyelectrolytes and non-ionic surfactants are of interest. The surface activity of solutions of composite systems based on polyethyleneimine (PEI) and ethoxylated isooctylphenol (OP-10), PEI and ethylene and propylene oxide block copolymer in pure and mineralized water at the water/air, water/oil interfaces have been studied. In comparison with pure water, a medium salinity causes the increase of solutions surface tension of the surfactants and their mixtures with PEI by 2-4 mJ/m 2 . The surface tension value increases weakly (by 1-4 mJ/m2) under the mineralization of water. At increased relative concentration of OP-10, ethylene and propylene oxide block copolymer, patterns of surface tension change are similar to those ones in pure water. The wetting action of salt solutions of PEI and block copolymer on the oil substrate formed on the glass plate surface was established.

Liquid–Liquid Equilibrium of Aqueous Biphasic Systems Containing Ethylene Oxide–Propylene Oxide Block Copolymers and Maltodextrins

This work presents liquid–liquid phase equilibrium data of ternary systems formed by aqueous mixtures of ethylene oxide–propylene oxide block copolymers and maltodextrin. Phase diagrams were obtained for five copolymers (with EO ratios ranging from 20 % to 80 % and molar masses ranging from 1900 g·mol–1 to 8400 g·mol–1) and three maltodextrins (with number averaged molar masses of 990 g·mol–1, 1500 g·mol–1, and 3000 g·mol–1) at 298.2 K and 308.2 K. The main factor influencing the phase diagrams is the ratio between ethylene oxide and propylene oxide chain sizes. The size distribution of maltodextrin was studied through gel permeation chromatography, and the size distribution of some equilibrium phases was also determined. Maltodextrin was found to partition unevenly between equilibrium phases, with larger molecules being excluded from the polymer-rich phases. The phase equilibrium was modeled using the UNIQUAC equation and with the consideration that maltodextrin can be represented by six pseudocomponents...

The effects of ethylene oxide–propylene oxide–ethylene oxide block copolymers on the physical properties of soils

The impact of a series ethylene oxide–propylene oxide block copolymers upon the physical properties of a sandy soil has been investigated. Specifically the impact upon the saturated hydraulic conductivity, water retention and water imbibition was examined. It was shown that soils exposed to aqueous solutions containing these block copolymers have reduced hydraulic conductivities. It was concluded that this could be due to the dispersion of fine grained materials or through changes in pore size brought about by swelling. Imbibition into soils that had been exposed to the block copolymers was enhanced. However the effect of the block copolymers upon water retention was complex. These block copolymers are surface active and as such will reduce surface tension to some extent or another. This should result in reduced water retention. It was observed that some of the block copolymers investigated did lead to reduced water retention. However some actually increased water retention. It is proposed that this was due to the effect that the block copolymers have upon wetting.

The impact of four ethylene oxide–propylene oxide block copolymers on the surface tension of dispersions of soils and minerals in water

A comprehensive series of aqueous solutions of four ethylene oxide–propylene oxide–ethylene oxide block copolymers (EPE) of varying concentrations have been prepared. The EPE molecules are amphiphilic with the P blocks providing the hydrophobic segment of the molecules and the E blocks providing the hydrophilic parts. The surface tension of these solutions has been measured and compared with the surface tension of dispersions of soils (a clay soil and a sandy soil) and minerals (quartz–silica sand, bentonite and kaolinite) in the same aqueous solutions. It is observed that all the block copolymers reduce the surface tension of water; the extent to which it is reduced is determined by the surface activity of the EPE block copolymer, which in turn is related to the balance between the sizes of the P and E blocks. It is further observed that the in the presence of soil the surface tension increases as a result of block copolymer adsorption to the soil/water interface. The extent of adsorption appears to be related to the texture of the soil – the clay soil used in this investigation adsorbs more block copolymer than the sandy soil. In the presence of the mineral phases the surface tension reductions are variable. With bentonite the EPE block copolymers are completely adsorbed at low EPE concentrations as shown by surface tension values that are the same as those measured for pure water. Adsorption to kaolinite is limited and once the adsorption sites have been filled the surface tension of the aqueous phase is approaches the surface tension of the same solution without the presence of bentonite. On the other hand the silica sand is a poor adsorbent. Adsorption to the mineral phases is also dependent upon the relative hydrophobicity of the block copolymer. The more hydrophobic (as inferred by the critical micelle concentration) the copolymer the less readily it is adsorbed by the mineral phases. Thus relatively hydrophobic EPE block copolymers produce a relatively large decrease in surface tension and are less readily adsorbed by the soil and mineral phases. It is concluded that the presence of EPE block copolymers in soils can result in the drainage of soil water from the saturated zone as a result of surface tension reductions. However the extent of drainage is related to the surface activity/molecular composition of the EPE block copolymer; the textural class of the soil and the nature of the minerals present in the soil.

Characterization of ethylene oxide–propylene oxide block copolymers by combination of different chromatographic techniques and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy

Block copolymers of ethylene oxide (EO) and propylene oxide (PO) are characterized by combination of two-dimensional chromatography and MALDI-TOF-MS. Liquid chromatography under critical conditions (LCCC) is used as first dimension and fractions are collected, mobile phase evaporated and diluted in the mobile phase used in second dimension (SEC or LAC). This two-dimensional chromatography in combination of MALDI-TOF-MS gives information about purity of reaction products, presence of the byproducts, chemical composition and molar mass distribution of all the products.

Altering the spreading coefficient of coal tar systems using ethylene oxide–propylene oxide block copolymers

The impact of poloxamine copolymeric surfactants upon the spreading coefficient of coal tar in a three phase system comprising water, coal tar and air has been investigated. The poloxamines are branched ethylene oxide (EO) propylene oxide (PO) block copolymers which are frequently used in pharmaceutical formulations. They have low mammalian toxicities and may therefore prove useful in surfactant enhanced aquifer remediation schemes where there is regulatory concern over the use of surfactants in groundwater. The purpose of this study was to investigate the conditions under which spreading coal tar films are converted into entrapped lenses. To that end, measurements were made of the surface tension of a range of aqueous poloxamine solutions using the du Nöuy ring technique and coal tar aqueous phase interfacial tensions using drop shape analysis. The poloxamines demonstrated surface activity by reducing the surface tension of water and the coal tar/water interfacial tension. However, there were differences in the extent to which the various poloxamines reduced the interfacial and surface tensions, which was clearly related to their molecular composition. In particular, the most effective compounds were those with high PO:EO ratios. All the poloxamines investigated altered spreading conditions. It was demonstrated, however, that those poloxamines having a relatively high PO mass and a high PO:EO compositional ratio were the most effective in altering the spreading conditions from spreading to non-spreading.

Phase equilibrium in aqueous two-phase systems containing ethylene oxide–propylene oxide block copolymers and dextran

Phase equilibrium of aqueous two-phase systems containing the polysaccharide dextran and ethylene oxide (EO)/propylene oxide (PO) triblock copolymers was investigated in this work. Phase diagrams at 25.0 °C were experimentally obtained for systems formed by either dextran 19 (average molar mass of 8200 g mol −1) or dextran 400 (average molar mass of 236 kg mol −1) and one of the following block copolymers F38, F68, F108, P105 and P103, which present different structures in terms of EO/PO ratios and molar masses. It was possible to assess the influence of the polymer features on the phase equilibrium: the main factors affecting phase equilibrium being the size of dextran molecule and the structure (mainly the EO/PO ratio) of the copolymer. The Flory–Huggins equation was used to correlate the experimental data with good qualitative agreement, allowing the inference that changes in the copolymer hydrophobicity are the main responsible for the observed phase diagrams.

Anomalous clouding behavior of an ethylene oxide–propylene oxide block copolymer in aqueous solution

Partial phase diagram of a polyethylene oxide–polypropylene oxide–polyethylene oxide polymer (EO 6–PO 30–EO 6), pluronic L62, in water, shows two cloud points (CP) in the concentration range (5–25 g dl −1). The phase behavior of L62 solutions markedly changes in the presence of neutral salts. While micellization of L62 is not favored by the presence of sodium chloride exerting ‘salting out’ action, sodium thiocynate which increase CP (salting in) favors micellization of the copolymer. The results of double CP and salt effect are discussed in terms of micellization of the copolymer. The critical micelle concentration (CMC) as determined by surface tension, dye spectral change and hydrodynamic micelle size from dynamic light scattering are reported and compared with similar systems.

Effect of ethylene oxide and propylene oxide block copolymers on the permeability of bilayer lipid membranes to small solutes including doxorubicin

The effects of ethylene oxide and propylene oxide block copolymers (pluronics) on the permeability of several weak acids and bases through bilayer lipid membranes have been studied by the methods of monitoring (1) pH shifts near planar bilayers, (2) doxorubicin fluorescence quenching inside liposomes, and (3) current transients in the presence of hydrophobic anions. It has been shown that pluronics facilitate the permeation of comparatively large molecules (such as 2- n-undecylmalonic acid and doxorubicin) across lipid bilayers, while the permeation of small solutes (such as ammonium and acetic acid) remains unaffected. Pluronics also accelerate the translocation of large hydrophobic anions (tetraphenylborate). The effect of pluronics correlates with the content of propylene oxide units: it is enhanced when the portion of polypropylene oxide block in the copolymer is increased. The action of the pluronic on lipid membrane permeability differs from the effect of the conventional detergent Triton X-100, which does not affect doxorubicin transport if added at concentrations similar to those used for pluronics. It has been proposed that pluronics accelerate the processes of solute diffusion within lipid bilayers (in a structure-dependent manner) rather than influencing the rate of solute adsorption/desorption on the membrane surface. We suppose that the effect of pluronics on doxorubicin permeation across lipid bilayers along with the known effect on the multidrug resistance protein determines its influence on the therapeutic activity of anthracycline drugs.

Interaction of tumor and normal blood cells with ethylene oxide and propylene oxide block copolymers

Ethylene oxide and propylene oxide block copolymers (pluronics) are widely known as agents that promote drug penetration across biological barriers. We have studied the interaction of normal and malignant blood cells with pluronics L61 and P85 that have different hydrophobicity. SP2/0 myeloma cells accumulated pluronics while normal cells adsorb most of the polymer on the surface. Interaction of pluronics with cells resulted in drastic changes of membrane microviscosity. Tumor cell membrane microviscosity decreased after pluronics adsorption, in contrast to normal cells, whose membrane microviscosity was enhanced. We suppose that sensitivity of tumor cell membrane microviscosity to the pluronics action correlates with its permeability for molecular substances.

Auto-oxidation products of ethylene oxide and propylene oxide block copolymers

The chemical composition, functionality, MWD and critical concentration of micelle formation of the auto-oxidation products of the block copolymer of ethylene and propylene oxides in equimolar composition are characterized and it is shown that the factors most sensitive to auto-oxidation are the appearance of hydroperoxide and carbonyl groups in the polymers and change in their MWD. The kinetic method of studying the reaction of the hydroperoxide groups with potassium iodide and ESR showed that they are located in the polypropylene oxide block of the copolymer.

Melting behavior of ethylene oxide–propylene oxide (sym‐EPE) block copolymers

AbstractMelting points have been measured for several ethylene oxide–propylene oxide block copolymers (sym‐EPE) chosen from the Pluronic range. Melting points of the block copolymers are lower than those of the corresponding poly(ethylene oxide) homopolymer by up to 4°C. The melting point depressions are much smaller than those observed for comparable sym‐PEP block copolymers.

Melting behavior of ethylene oxide–propylene oxide (sym‐PEP) block copolymers

AbstractMelting points and lamellar thicknesses have been measured for ethylene oxide–propylene oxide block copolymers (sym‐PEP) with central poly(ethylene oxide) block lengths of 70–100 chain units and end poly(propylene oxide) block lengths of 0–30 chain units. Melting points of the block copolymers are lower than those of the corresponding poly(ethylene oxide) homopolymer by an amount (up to 15°C) which increases as the poly(propylene oxide) block length increases. Most samples have more than one melting transition, which can be assigned to variously folded chain crystals. End interfacial free energies σe for the various crystals have been estimated by use of Flory's theory of melting of block copolymers. For a given crystal type (e.g., once‐folded‐chain) σe is higher the longer the chain length of the end poly(propylene oxide) blocks. For a given copolymer σe is lower, the more highly folded the poly(ethylene oxide) chain.