The object of the invention concerns a quaternary ammonium salt of formula (I) wherein the substituents R.sub.5, R.sub.6 are independently chosen between hydrogen H and a radical R.sub.0, wherein the radical R.sub.0 consists of the structure of formula (II) wherein the substituent R.sub.1 is chosen from the group consisting of: hydrogen, methyl, isopropyl, sec-butyl, isobutyl, ethylenemethylthio, benzyl, para-hydroxybenzyl and 3-methylene-1H-indole, wherein the substituents R.sub.2, R.sub.3, R.sub.4 are independently chosen from the group consisting of: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, wherein m is an integer number comprised between 1 and 22, wherein the counteranion X.sup.− is chosen from the group of carboxylic acids consisting of: formic acid, acetic acid, unsaturated monocarboxylic acids, tartaric acid, adipic acid, aldaric acid, oxalic acid, phthalic acid, azelaic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, maleic acid, malic acid, fumaric acid, suberic acid, citric acid, isocitric acid, fatty acids, acid amino acids, keto acids and aromatic carboxylic acids, and wherein n is comprised between 2 and 20.

A recording medium for producing a recorded matter having a three-dimensional image comprises: a substrate; and a foaming layer being provided on the substrate and containing a foaming material which foams with heat and a binder resin. A contact angle of water to a surface of the foaming layer 30 seconds after the water is brought into contact with the surface of the foaming layer is 30° or more and 80° or less, and a ratio of a diameter of a water droplet 30 seconds after the water is brought into contact with the surface of the foaming layer to a diameter of the water droplet 0.01 seconds after the water is brought into contact with the surface of the foaming layer is 1.3 times or less.

A recording medium for producing a recorded matter having a three-dimensional image comprises: a substrate; and a foaming layer being provided on the substrate and containing a foaming material which foams with heat and a binder resin. A contact angle of water to a surface of the foaming layer 30 seconds after the water is brought into contact with the surface of the foaming layer is 30° or more and 80° or less, and a ratio of a diameter of a water droplet 30 seconds after the water is brought into contact with the surface of the foaming layer to a diameter of the water droplet 0.01 seconds after the water is brought into contact with the surface of the foaming layer is 1.3 times or less.

Some reservoirs have tight oil formations, such as the Changqing reservoir. The surfactant polymer flooding and low-tension gas flooding are two potential chemical flooding methods for use in tight oil formations. In these methods, an oil displacement agent, or surfactant, is added. Derivatives of nonionic surfactants with extended chains (by propylene oxide and ethylene oxide) from di-alkyl alcohols were developed and tested. A synergistic blend of surfactants was developed between the di-alkyl chain surfactants and a commercially available anionic surfactants that lowers interfacial tension and improves surfactant solubility in high salinity water and oil.

Some reservoirs have tight oil formations, such as the Changqing reservoir. The surfactant polymer flooding and low-tension gas flooding are two potential chemical flooding methods for use in tight oil formations. In these methods, an oil displacement agent, or surfactant, is added. Derivatives of nonionic surfactants with extended chains (by propylene oxide and ethylene oxide) from di-alkyl alcohols were developed and tested. A synergistic blend of surfactants was developed between the di-alkyl chain surfactants and a commercially available anionic surfactants that lowers interfacial tension and improves surfactant solubility in high salinity water and oil.

The present invention relates to a surfactant-stabilized fluid interface, comprising a layer of surfactant and a first compound containing a hydrophobic part covalently linked to a molecular recognition site, wherein the surfactant-stabilized fluid interface has a first fluid on one side and a second fluid on the other side, wherein the surfactant stabilizes the fluid interface, wherein the hydrophobic part of the first compound is interacting with the layer of surfactant by secondary non-covalent interactions and the molecular recognition site of the first compound extends from the layer of surfactant, and wherein the surfactant is a block-copolymer having at least one hydrophilic block and at least one hydrophobic block. The present invention further relates to a dispersion comprising one or more droplets having a surfactant stabilized fluid interface.

There is provided an emulsifier comprising at least one C.sub.8 to C.sub.18 fatty acid diethanolamide, at least one C.sub.12 to C.sub.24 fatty acid, at least one C.sub.6 to C.sub.18 alcohol ethoxylate and optionally at least one sorbitan ester and/or at least one alkylene glycol monoalkyl ether. There is additionally provided emulsions comprising a fuel, water and an emulsifier and methods of producing emulsions.

Surfactants capable of releasing and/or dissolving polymers to form water-soluble or water-dispersible polymer solutions are disclosed. In addition, polymer compositions containing a water-in-oil emulsion comprising the surfactant are provided and can be used, for example, in methods of dissolving a polymer. These surfactants and polymer compositions can be used in various industries including for water clarification, papermaking, sewage and industrial water treatment, drilling mud stabilizers, and enhanced oil recovery.

A method may include providing a single-phase cleanout fluid comprising a first nonionic surfactant with a hydrophilic-lipophilic balance (HLB) greater than 10, a second nonionic surfactant with an HLB greater than 10, a third nonionic surfactant with an HLB of less than 10, and a solvent; preparing a cleanout pill by mixing the single-phase cleanout fluid with a brine; and displacing a fluid in a wellbore using the cleanout pill.

A method may include providing a single-phase cleanout fluid comprising a first nonionic surfactant with a hydrophilic-lipophilic balance (HLB) greater than 10, a second nonionic surfactant with an HLB greater than 10, a third nonionic surfactant with an HLB of less than 10, and a solvent; preparing a cleanout pill by mixing the single-phase cleanout fluid with a brine; and displacing a fluid in a wellbore using the cleanout pill.