Method of measurement of liquid-liquid phase transition parameters in aqueous solutions of amphiphiles
FIELD: measurement equipment.
SUBSTANCE: invention relates to a boundary area between physics, chemistry and biology and can be used in scientific and industrial laboratories for determination of parameters of phase transition in water and influencing conditions (pressure, temperature), influence of substances and fields. The method of measurement of parameters of liquid-liquid phase transition in amfifil water solutions by measurement of thermal effect of amphiphile solution dilution by PEO solutions depending on amphiphile concentration is offered.
EFFECT: improvement of reliability of identification and separation of two oscillating states of the system.
4 cl, 1 dwg
The invention relates to a border area between physics, chemistry and biology. Can be used in scientific and industrial laboratories to determine the parameters of the phase transition in water and influence of the conditions (pressure, temperature), additives, substances and fields. This data is judged on the use of surfactants in various industries and agriculture.
The known method of measuring the parameters of the phase transition liquid-liquid (L-L-go) in aqueous solution (patent RF 2433386). The method allows to measure the average concentration of the phase transition or the critical micellization concentration (CMC) and the degree of cooperativity, the area of concentration, where the transition occurs, the depth of the transition. Furthermore, it is known (Huang et al. // PNAS. 2009. V. 106. P. 15214) that the water on the scale of approximately 1 nm forms at room temperature shimmering fluctuations (clusters) low density with strict tetrahedral coordination (LDL) and high density fluctuations with broken H-bonds (HDL), which are in balance.
The appearance amphiphiles in water shifts the equilibrium towards formation of clusters of LDL. Upon reaching the CMC in water is achieved, the average concentration of L-L transition. Water clusters oscillate between clusters of LDL and HDL concentration in the transition region. Oscillation of ensembles of clusters of water soprovojdayut� oscillation ensembles of two types of micelles (J. A. Mirgorod // Zhurn. structure. chemistry. 2008. Kzt49. P. 920). Oscillations in ensembles of water clusters and micelles occur quickly 103-10-8C. Devices can not yet be fixed (split) in time existence of a shimmering clusters and micelles. Methods and small-angle x-ray scattering reveal only spherical or ellipsoidal micelles amphiphiles (Cabane V. et. al. // J. Physique. 1985. V. 46. P. 2161).
The known method (patent RF 2433386) does not identify two oscillating system state.
An object of the invention is to provide a method of identification (visualization) and separation of the two oscillating States of the system (energy distributions of the ensemble of clusters).
The technical result according to the invention is achieved by dilution of a solution of amphiphile in the field of critical micelle concentrations of the solution of polyethylene oxide (PEO) and measurement of thermal effect of dilution depending on the concentration of amphiphile. Prepare a solution of amphiphile with a concentration above its CMC. In other volumetric glassware prepare a solution of PEO, about 100 times more dilute than the solution of amphiphile in weight percentage. For experiments take PEO with a molar mass of from 2000 to 100,000 g·mol-1. It is desirable to take PEO with a narrow molecular weight distribution. On isotherme�Eskom calorimeter spend thermometric titration. By measuring thermal effects depending on the concentration of amphiphile curve thermometric titration (see drawing). On the curve there are two opposite thermal effects of the "hump". They indicate the existence of two processes in the area of concentration micellization amphiphiles. From small concentrations occurs first endothermic process, and then exothermic. Different processes reflect the interaction of PEO with two types of micelles, the formation of which prevails in different areas of concentrations of amphiphile. With PEO molar mass, lesser 2000 g·mol-1two processes are not visualized. With a molar mass greater then 100,000 g·mol-1they appear bad. Solutions during the titration must be transparent. They should not form a precipitate or become cloudy.
Humps reflect the distribution of the ensemble of clusters energy (enthalpy) dilution in the concentration range of amphiphile in States A and B. When each of multiple concentrations in the range L-L-transition is the distribution of States A and B. Thermometric curve shows the cumulative distributions for the concentrations. Temperature, pressure, electrolyte, electromagnetic and acoustic field affect this distribution. From 25 to 5°C humps increase and bring�I, and at 65°C disappear.
The invention is illustrated by an example. Prepare a 10% (wt.) a solution of sodium dodecyl sulfate (DSS) and 0.1% (wt.) a solution of PEO molar mass of 3350 g·mol-1. KCM DCS 8·10-3M. isothermal microcalorimetry spend thermometric titration of a solution of PEO solution DCS at 15°C. Then build a graph of thermal effect on the concentration DCS (see drawing). The drawing on the interfaces direct with curves define the beginning of c1=4·10-3M and end with C2=28·10-3M L-L transition. Two s-shaped curves - average concentrations of cA=6·10-3M, cB=22·10-3M and enthalpy of formation of the ensemble of clusters in the position AND ΔHA=10 kJ·mol-1In ΔHB=-4 kJ·mol-1. Concentrations are determined so that the area of each triangle below the function and above the function ΔH(x) were the same.
Thus, using supplements PEO in the solution of amphiphile and measurement during the additive thermal effect of dilution can be clearly seen models shimmering clusters of solutions amphiphiles in the field of micelle formation from c1to c2and to determine their energy options. This phenomenon allows the simulation of relaxation processes in solutions amphiphiles in the study, for example, penetration of drugs through the skin under the influence of ultrasound or HC�increase oil production under the influence of the electromagnetic field.
1. Method of measurement of parameters of the phase transition liquid-liquid in aqueous solutions amphiphiles measurement of thermal effect of dilution of the solution of amphiphile solutions PEO, depending on the concentration of amphiphile.
2. A method according to claim 1, characterized in that the take polyethylene oxide with a molar mass of 2000-100000 g·mol-1.
3. A method according to claim 1, characterized in that as parameters of the phase transition determine the region of concentrations where phase transition occurs, the average concentrations of the two distributions of ensembles of clusters, the enthalpy of the distributions of the two ensembles of clusters.
SUBSTANCE: proposed method comprises temperature measurement, control over sorption in absorption of gas-air mix with reference substances by carbon sorbents in dynamic conditions. Note here that remote computer-aided visualisation of thermal fields is used to record sorbent surface temperature variation caused by gas-air flow with absorbed component and to control depletion of protective properties of filtration absorbing articles.
EFFECT: proximate estimation of thermophysical properties of filtration absorbing systems.
SUBSTANCE: disclosed is a method of determining the glass-transition point of tetrazole-based polymer composite materials based, according to which the glass-transition point is determined from the change of slope of a curve of temperature versus the inverse of dielectric constant 1/ε'=f(T).
EFFECT: high accuracy and reliability of determining the glass-transition point of tetrazole-based polymer composite materials.
4 dwg, 1 tbl
FIELD: measurement equipment.
SUBSTANCE: method is based on experimental determination of temperature of avalanching disintegration of cooling liquid on a hot surface, in static conditions, without liquid flow.
EFFECT: simplification of rejecting different lots of cooling liquid, decreasing amount of substance in investigated sample and consequently improved safety for personnel engaged in tests.
FIELD: measurement equipment.
SUBSTANCE: method for examination of thermophysical properties of liquids is proposed. It implies that a metal probe of vibration viscosity metre equipped by a temperature sensor is placed to a metal cell with a liquid sample equipped by a temperature sensor. The probe is set to harmonic vibration mode, the cell temperature is changed by a controlled cooling-heating device. Temperature, amplitude, phase and vibration frequency of the probe are measured and density, viscosity and thermal diffusivity of the liquid is determined depending on its temperature. Measurements are made to define dependency on the temperature of the liquid's optical transmission near the probe for the moments when the probe passes its equilibrium position. Device for the method implementation comprises a cell, a controlled cooling-heating device, spherical metal probe of vibration viscosity metre placed inside the cell. The probe and the cell are equipped by temperature sensors. The cell is also equipped with a fibre-optical sensor of liquid optical transmission which is set next to the probe.
EFFECT: improved accuracy of measurement.
2 cl, 2 dwg
FIELD: measurement equipment.
SUBSTANCE: substance consists in availability of a measurement device and a thermoresistive sensor of phase condition in a device for determination of phase condition of a gas and liquid flow, and the sensor comprises a printed circuit board arranged along the axis of flow movement and rigidly fixed by one short side with a sensitive element installed on it and made in the form of a substrate, on which a film resistor of the "point" design (a thermistor) is installed. The sensitive element is installed in the reference point along the vertical axis of the pipeline cross section and is connected with the measurement device, which comprises a metering circuit and a microcontroller with program control and is designed to measure variation of thermistor resistance, connected with variation of the phase condition of the medium in horizontal layers of the gas and liquid flow, and signal processing. At the same time the sensitive element of the sensor by one short side of the substrate is fixed on the edge of the short non-fixed side of the printed circuit board. The film resistor (thermistor) placed on the substrate is displaced towards the edge of the free short side of the substrate and is arranged at the distance of not more than 0.5 mm from this edge. Contact sites designed for connection of the substrate to the printed circuit board are arranged opposite to the thermistor at the opposite short side of the substrate.
EFFECT: higher efficiency of a device to determine phase condition of a gas and liquid flow.
SUBSTANCE: method for determining temperature of full polymorphous transformation of heat-resistant two-phase titanium allows of (α+β)-martensitic class is proposed, which involves preliminary preparation of a specimen by means of multistage heat treatment of the latter, which is performed immediately in a differential thermal analysis (DTA) instrument in atmosphere of cleaned argon and its investigation using DTA method. Heating of the alloy specimen to single-phase β-area, supercooling below temperatures of active diffusional decay of β solid solution, short-term exposure and repeated heating to the single-phase area is performed. Fixation of dependence of a DTA signal on temperature and calculation of values of derivative of DTA signal on temperature is performed, and temperature of completion of full polymorphous transformation is determined as per maximum on the curve of the first derivative of DTA signal at repeated high-temperature heatinge.
EFFECT: improving determination accuracy of temperature of full polymorphous transformation in heat-resistant two-phase titanium alloys.
SUBSTANCE: oil sample is heated with one-time temperature control, the sample is continuously cooled with simultaneous measurement of shear stress. Chilling point is determined from temperature corresponding to the first abrupt increase in shear stress, and bulk freezing point is determined from temperature corresponding to the second abrupt increase in shear stress. The sample is heated to temperature of 60-80°C. Heating and temperature control of the sample is carried out while revolving the viscometer cylinder and the sample is cooled at a rate of 1-2°C per minute.
EFFECT: high information value and reliability of the analysis method.
FIELD: test engineering.
SUBSTANCE: body under study is brought into thermal contact with the reference body in the plane in which the local circular heater is located. At regular intervals of time the difference of values of the temperature between the heater and the point of plane of contact of the body under study and reference body is measured. The tests end up in excess of the specified value by the controlled dynamic parameter. The dependence of the current value of thermal activity on the temperature of the body under study is made. The structural transitions in polymeric materials are determined by the presence of peaks on dependence of the current value of the thermal activity on the temperature of the body under study.
EFFECT: improved method.
SUBSTANCE: method of determining volatility and heat of vaporisation of a mixture of liquid substances from the rate of evaporation from a flat surface involves establishing a correlation relationship between volatility values, calculated using known reference data, for individual liquid substances selected as calibration liquids, and the rate of evaporation thereof, determined based on data from thermogravimetric analysis carried out in isothermic conditions when an equilibrium state is achieved. The rate of evaporation of the analysed mixture is determined and the volatility value is found from the correlation relationship. The heat of vaporisation of the mixture of liquid substances in the analysed temperature range is determined using the relationship between the found volatility values and temperature. The value of the heat of vaporisation is determined from the value of the slope of a linear graph, the abscissa of which is the value of the inverse absolute temperature and the ordinate is the logarithm of the product of the experimentally determined volatility value and the absolute temperature value.
EFFECT: high reliability and objectivity of estimating volatility of not only individual liquids, but also mixtures thereof at different temperatures, broader functional capabilities of the method of determining volatility.
2 cl, 6 dwg
SUBSTANCE: method involves separate temperature control of cylindrical samples which make up a eutectic system, one of which has the analysed composition and the other is homogeneous, for example, consists of a pure substance. The samples are brought into contact at analysis temperature which is higher than the eutectic point, and the position of imaging point of the analysed alloy relative the solidus curve is determined from the state of the liquid layer formed between the samples.
EFFECT: invention enables more accurate plotting of a solidus curve on a phase diagram.
3 dwg, 1 tbl, 1 ex
SUBSTANCE: method of determining thermo-oxidative stability of lubricating materials involves heating the lubricating material in the presence of air and mixing. Oxidised lubricating material is then collected. Oxidation process parameters are then photometered and determined using graphical curves. Two samples of the lubricating material of constant weight are tested separately with and without a catalyst. While heating, the two samples of lubricating material of constant weight are tested successively with and without a catalyst, stirred while periodically varying testing temperature from temperature at the onset of oxidation and maximum temperature. Temperature is the lowered from maximum temperature to temperature at the onset of oxidation over a constant period of time. After each testing temperature, with and without a catalyst, the samples are weighed, the weight of the evaporated sample and evaporation number are then determined as a ratio of the weight of the evaporated sample to the weight of the remaining sample. By photometering, the light flux absorption factor with and without catalyst is determined, the thermo-oxidative stability factor is determined as a sum of light flux absorption factor and evaporation number. Further, the influence coefficient of the catalyst KVK on oxidative processes is determined using the formula KVK=KK/K, where KK and K are thermo-oxidative stability factors of samples of the lubricating material with and without catalyst, respectively. A curve of the influence coefficient of the catalyst on the oxidative processes versus the testing time is then plotted, and thermo-oxidative stability of the lubricating materials is then determined from values of the influence coefficent of the catalyst on the curve. If KVK>1, thermo-oxidative stability is falling, and if KVK<1 thermo-oxidative stability is increasing.
EFFECT: high information content of the method of determining thermo-oxidative stability of oxidation and evaporation processes during periodic variation of the testing temperature.
3 dwg, 1 tbl
FIELD: investigating or analyzing materials.
SUBSTANCE: thermograph comprises differential thermocouple and aluminum thermal unit provided with two symmetrically arranged cylindrical holes for crucible with specimen and standard. The crucibles are made of cylinders with caps provided with copper pipes for hot junctions of Chromel-cupel thermocouples. The wires of the thermocouples are housed in the two-channel ceramic rods. The thermoelectric heating of the unit is provided with the use of temperature-sensitive resistor made of nichrome wire. The unit is mounted in the steel sealed housing with a lid and provided with a device for locking it inside the housing during cooling and heating.
EFFECT: simplified design and enhanced accuracy of measuring.
FIELD: polymorph processes in metals and electro-conducting materials.
SUBSTANCE: method of measuring temperature of polymorph transformation is based upon heating for hardening till temperature providing free sag of rigidly tight sample. The temperature should correspond to α→β polymorph transformation.
EFFECT: improved precision of measurement.
FIELD: measurement technology.
SUBSTANCE: device has trier provided with holder and measuring probe provided with thermocouple placed inside the trier. Thermocouple is used which has time constant less than 1,5 sec. Volume of part of thermocouple submerged into salt melt relates to volume of cup of the trier as (5x10-3-10-2):1. Precise value of temperature can be achieved as well as high degree of reproducibility.
EFFECT: improved precision; prolonged service life of thermocouple.
9 cl, 4 dwg
FIELD: test equipment.
SUBSTANCE: metal probe of vibration viscosimeter is disposed inside metal dish in tested fluid to make it thermally isolated from outer space. Viscosimeter is excited with preset frequency and with preset force. Temperature of the dish is changed monotonously and continuously to follow specified rule at speed to exceed speed of establishing processes of change in temperature of tested liquid inside the dish. Temperature of the probe is measured within whole preset range of changes in temperature of the dish as well as amplitude and/or phase and/or frequency of oscillations of the probe. Density, viscosity, thermal conductivity, heat capacity and thermal diffusivity of tested fluid are measured depending on fluid's temperature from the relation of heat diffusivity of fluid and from the relation of viscosimeter's probe forced oscillations. The main feature of the device realizing the method has to be the metal probe of viscosimeter made in form of copper ball or silver ball disposed in fluid for thermal insulation onto rod made of thermo-insulating material. Measuring converter of probe's temperature is made in form of thermocouple and built inside probe. Second measuring converter of probe's temperature, also made in form of thermocouple, is placed onto bottom of metal dish thermally insulated from environment.
EFFECT: improved efficiency of test.
10 cl, 5 dwg
FIELD: inspection of quality of oil products.
SUBSTANCE: permanent-weight lubricant is subject to heating in thermo-stable glass cup at three temperatures at least, which temperatures exceed that one of beginning of oxidation and then it is subject to mixing by glass mixer at constant speed during 12 hours or less. Samples for photometry are selected in equal time intervals. Factor of absorption of light flux by oxidized oil Ability to evaporation is measured by weighing sample before and after test. Graphical dependences of theses parameters are built relatively temperature of testing. Thermal-oxidative stability of lubricant is determined by critical temperature of service ability, by temperature of beginning of oxidation and by temperature of beginning of oxidation.
EFFECT: improved efficiency of measurement.
FIELD: investigating or analyzing materials.
SUBSTANCE: method comprises heating specimens to be analyzed with a rate of 10 deg/min, using standard initial polymineral clays, selecting temperature intervals 20-200°C, 600-800°C, and 20-100° C from the thermo-analytic curves of the standards, determining the reference values in the intervals, determining mass losses, and choosing maximum values of the mass losses in the intervals for the calculation of the fraction ration of clays.
EFFECT: enhanced accuracy of measurements.
6 dwg, 1 tbl, 6 ex