Orientational ordering and spatial distribution of rod-like Janus nanoparticles in the lamellae diblock copolymers has been considered using a molecular theory based on simple model of Janus particle with two different interaction centres located at the particle ends. Order parameter and concentration profiles of Janus nanoparticles have been calculated numerically for different values of the nanoparticle length. It has been found that Janus nanoparticles are mainly located in the boundary region between the domains and are orientationally ordered in that region with a high orientational order parameter. This orientational order is induced by the interface and is determined by the different affinities of the two ends of the Janus particle with respect to the monomers of different domains. Comparison with block copolymers doped with symmetric nanoparticles indicates that polymer nanocomposites with Janus particles are expected to possess much larger dielectric anisotropy and thus can be considered as promising anisotropic nanomaterials which can be aligned by the external electric field.

Orientational ordering of rod-like nanoparticles in the lamellae phase of diblock copolymers has been considered theoretically using the model of a nanoparticle with two interaction centres. It has been shown that strongly anisotropic nanoparticles order spontaneously in the boundary region between the blocks where the orientational order is induced by the interface and by the interaction with monomer units in different blocks. The nematic order parameter possesses opposite signs in adjacent blocks which means that the nanorods are aligned parallel or perpendicular to the boundary between the blocks on different sides of their interface. Concentration and nematic order parameter profiles have been calculated numerically for different values of the nanoparticle length and compared with the results of recent computer simulations and with the results of the previous molecular theory based on nanoparticles of spherical shape. [GRAPHICS] .

The formation and decomposition of hydro-peroxides are the key stages of combustion. These stages strongly depend on the several factors accelerating or slowing this process. The aim of this work is to estimate experimentally which oil components act as inhibitors of initial stages of oxidation and which accelerate the process. The next aim is to explore the process of adsorption of oil components on the grain of rock, which turned to be also a key process in the low temperature oxidation. The work includes experimental part where differential scanning calorimeter (PDSC) experiments with pure saturates, mixtures of saturates and aromatic oil fractions and mixtures of saturates, aromatic fractions and rock samples are considered. Effects of inhibition and acceleration of the initial oxidation stages are explored.

Summary Application of air injection as an enhanced oil recovery method involves high risks, both economic and technological. One of the main risks of this technology is the lack of oil self-ignition during air injection and difficulties in creating a combustion front in the reservoir. In a number of fields the reservoir thermal and pressure conditions and the oil properties cause spontaneous ignition (mainly light oil fields with a high reservoir temperature), while in other fields special ignition programs are required. In the present paper three possible ways of air injection process development are shown: the method of "pushing" oil with air without combustion front appearance, in-situ combustion (ISC), and thermogas treatment, or, using the American terminology, high pressure air injection (HPAI). The field’s properties that determine which way in-situ combustion process will develop are identified. One way to determine in which of these three ways the process will develop is to study the oxidation characteristics using the pressurised differential scanning calorimetry (PDSC). For the improved study of the combustion process DSC experiments of oil samples oxidation reactivity, oil-saturated core and other actively reactive substances are performed. High precision of modern thermo-analytical PDSC equipment enables investigating the initial stages of oxidation reactions of hydrocarbons and describing the initial stages of the reaction in terms of the Arrhenius theory as well as the theory of chain reactions. This approach allows us to identify the most reactive oil components (oil paraffins), and describe the process of their oxidation in terms of the chain mechanism of birth and death of free radicals. It is shown how oil can change its reaction activity at the reservoir rock samples; the activity among others, is caused by the adsorption of asphaltenes and oxidised components on the core surface during the heating process. In addition, the unsteady type of oil (tarry light oil) has been studied, oxidation of which is accompanied by transition of resins to secondary asphaltenes, which, as it has been first shown, in the presence of core significantly increases the amount of fuel. In the case when the pressure and temperature conditions of the reservoir and oil reactivity prevent spontaneous ignition, some cases for combustion initiation have been considered. It is shown that due to PDSC experimental results a comparison of hydrocarbon and other fluids in order to find a reagent with the lowest self-ignition temperature can be achieved. It is shown that vegetable oil additions to oil can significantly reduce the temperature of the heat output, and can serve as oil ignition initiators for air injection. Technical aspects of combustion ignition are also discussed in the paper. The technology integrate heating agent and reactive hydrocarbon liquid injection, which reduces the lack of ignition risks in the oilfields with low temperature.

Successfully operating in the USSR program of field tests and development of modern methods of enhanced oil recovery allowed in a short period to raise an additional oil production through the use of modern methods of oil recovery by 4 times. Due to the political and economic crisis associated with the collapse of the Soviet Union, the implementation of this national program was phased out. Currently, in order to overcome the negative trends of reproduction of resource base of oil industry the need to restore the state program of development and introduction of modern methods of enhanced oil recovery, as well as its economic stimulation.

Microstructuring in the bulk of a polymer globule in a solution that contains dimeric amphiphilic molecules, in particular, surfactants, is studied in terms of the weak-segregation theory. An inhomogeneous structure can result from a decrease in free energy with the orientation of amphiphilic molecules in the region of inhomogeneity owing to the interaction of hydrophobic and polar parts of the molecules with the solvent. For the sake of simplicity, we discuss the case of identical second virial coefficients of the interaction of monomer units and amphiphilic molecules with different energies of interaction of the hydrophobic and polar parts of the molecule with the solvent. By comparing the free energy for different types of microstructures, we predict that, with deterioration in the quality of the solvent, there is an initial formation of a homogeneous globule followed by formation of a body-centered cubic structure; a hexagonal cylindrical structure; and, finally, a lamellar structure. For a low degree of amphiphilicity, the transition from a homogeneous globule to only a lamellar structure occurs. An increase in the concentration of the amphiphilic substance in the surrounding solution hinders the formation of a globule but facilitates its microstructuring, which is also promoted by an increase in the volume of the amphiphilic molecule and the difference in the interaction energies of its hydrophobic and polar parts with the solvent. Phase diagrams of a globule’s state at different values of model parameters are plotted.

. A microphase separation in solutions containing a polymer and a mixture of two solvents, one of which consists of amphiphilic molecules (surfactant), is considered theoretically in the weak-segregation regime. A surfactant molecule is described as a dimer consisting of hydrophobic and polar parts. The energy gain due to the orientation of surfactant molecules can lead to the appearance of non-homogeneities in the solution, where density fluctuations cause the orientational ordering of surfactant molecules. The difference in the interaction energies of hydrophobic and polar groups of a surfactant with solvent is considered as a main reason for orienting surfactant molecules. The free energy is calculated for various morphologies (lamellar, cylindrical hexagonal, spherical particles arranged at different cubic lattices). The phase diagrams are presented. With worsening the solvent quality, the transitions from disordered to a macro-separated state at low polymer and surfactant concentrations or to a body-centered-cubic, then hexagonal, and then lamellar structure at high polymer and surfactant concentrations are predicted. The amphiphilicity degree of surfactant molecules should exceed a certain critical value to make a microstructure formation possible. The period of the lamellar microstructure decreases with increasing the surfactant and polymer concentrations.

The globular state of the homopolymer macromolecule in a blend composed of a poor solvent and an amphiphilic solvent (substrate), whose molecules tend to be aligned with the solvent concentration gradient in the inhomogeneity region, was theoretically studied. The size of a homogeneous globule and the substrate concentration in its volume were calculated in terms of a bulk approximation. After the transition of the macromolecule from the coil to the globule state, its volume first decreases with a decrease in temperature and then begins to grow due to substrate molecules penetrating the globule. The substrate concentration in the globule insignificantly exceeds that outside the globule at identical second virial coefficients of interaction between monomer units and between substrate molecules. The expression for the free energy functional depending on the volume fractions of the components and on the orientation of substrate molecules was examined in the ground-state approximation. The orientation effect leads to narrowing of the surface layer and to a decrease in the surface tension of the homogeneous globule, thereby increasing its stability with respect to the transition to the unfolded-coil state.

We consider the theoretical model of an amphiphilic macromolecule with a complex structure of hydrophobic/hydrophilic monomer units. Each unit consists of a hydrophobic group (H) in the backbone and a side hydrophilic group (P). The units are able to orient in the density gradient at the surface layer of a globule. First, we use the density functional method to obtain the surface tension at a flat surface. We obtain that the effect of orientation decreases the surface tension of an amphiphilic globule in comparison with the surface tension of a homopolymer globule of the same density. Therefore, the amphiphilic globule is more stable with respect to the transition to a coil conformation. Then, macromolecules with strong orientational ability of amphiphilic units are considered. The free energy of spherical, bead-like, disc-like and torus-like globules is analysed for flexible and rigid macromolecules. For very long macromolecules in poor solvent, it is predicted that a disc-like globule for flexible chains should be formed. It is shown that the coil–globule transition in amphiphilic macromolecules is in most cases accompanied by a disintegration of the initially formed globule into several 'bead globules'. Upon further increase of the attraction of hydrophobic units, these beads merge with each other with the formation of a disc-like or torus-like globule, depending on the chain stiffness.