Hydrophobic water. Hydrophobic part - Hydrophobe. Meaning and application in life

Hydrophobic substances

Hydrophobic matters (substances)

Solids that are not wetted by water. Wetted with oily liquids.

A brief electronic reference book on basic oil and gas terms with a system of cross-references. - M.: Russian State University of Oil and Gas named after. I. M. Gubkina. M.A. Mokhov, L.V. Igrevsky, E.S. Novik. 2004 .

See what “Hydrophobic substances” are in other dictionaries:

Hydrophobic ointment bases- Main article: Ointment bases Hydrophobic ointment bases ointment bases intended for dosage forms whose active ingredients are hydrophobic. The group of hydrophobic bases combines bases and their components that have different... ... Wikipedia

Hydrophobic coatings- thin layers of non-water-wettable substances on the surface of hydrophilic materials. G. p. are often called water-repellent, which is incorrect, because. water molecules do not repel from them, but are attracted, but extremely weakly (see Hydrophilicity and ...

Substances that can accumulate (thicken) on the surface of contact of two bodies, called the phase interface, or interfacial surface. On the interfacial surface of P. a. V. form an adsorption layer of increased concentration... ... Great Soviet Encyclopedia

surfactants (surfactants)- substances that can be adsorbed at the interface and cause a decrease in surface (interfacial) tension. Typical surfactants are organic compounds whose molecules contain lyophilic and lyophobic (usually hydrophilic and... ... Encyclopedic Dictionary of Metallurgy

Surfactants- (a. surfactants; n. grenzflachenaktive Stoffe, oberflachenaktive Stoffe; f. substances tensio actives; i. surfac tantes), substances with an asymmetric mol. structure, the molecules of which have a diphilic structure, i.e. contain lyophilic and... Geological encyclopedia

surfactants- Surfactant Substances that can be adsorbed at the interface and cause a decrease in surface area. (interfacial) tension. Typical surfactants are organic. compounds whose molecules contain lyophilic and lyophobic (usually hydrophilic and hydrophobic) at... Technical Translator's Guide

Surfactant species Substances with an asymmetric molecular structure, the molecules of which have a diphilic structure, that is, they contain lyophilic and lyophobic (usually hydrophilic polar groups and hydrophobic radicals) atomic groups. Diphilic... ... Oil and Gas Microencyclopedia

Explosives- (a. explosives, blasting agents; n. Sprengstoffe; f. explosifs; i. explosivos) chemical. compounds or mixtures of substances that, under certain conditions, are capable of extremely rapid (explosive) self-propagating chemicals. transformation with heat release... Geological encyclopedia

Ammonium nitrate explosives- (a. ammonal, ammonium nitrate explosives; n. Ammonsalpetersprengstoffe, Ammonnitrat sprengstoffe, ANC Sprengstoffe; f. explosifs nitres; i. explosivos de nitrato amonico) explosive mixtures, base. component of ammonium nitrate.... ... Geological encyclopedia

Blood-brain barrier- Relationship between brain tissue cells and capillary: 1. Ependyma 2. Neuron 3. Axon 4. Schwann cell 5. Astrocyte 6 ... Wikipedia

State educational institution of higher professional education

Ministry of Health of the Russian Federation

(GBOU VPO NSMU Ministry of Health of Russia)

Department of Medical Chemistry

Essay

HYDROPHILIC, HYDROPHOBIC, AMPHIPHILIC SUBSTANCES: IN NATURE AND IN THE HUMAN BODY.

(literature review)

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Introduction

Water is one of the most abundant substances on Earth. It covers most of the earth's surface. Almost all living things are composed primarily of water. In humans, the water content in organs and tissues varies from 20% (in bone tissue) to 85% (in the brain). About 2/3 of a person’s mass is water, in the body of a jellyfish up to 95% is water, even in dry plant seeds, water is 10-12%.

Water has some unique properties. These properties are so important for living organisms that it is impossible to imagine life without this compound of hydrogen and oxygen.

In relation to water, all substances are divided into two groups: hydrophilic - “loving water” and hydrophobic - “afraid of water” (from the Greek “hydro” - water, “phileo” - love and “phobos” - fear). The properties of these substances, as well as their significance in nature, will be discussed in our work.

Hydrophilic and hydrophobic substances

Hydrophilic substances (Greek “hydro” - water, “phileo” - love) are substances whose energy of attraction to water molecules exceeds the energy of hydrogen bonds (the energy of attraction between water molecules), therefore many hydrophilic substances are highly soluble in water.

Hydrophilic substances interact intensively with water molecules. Hydrophilicity is characterized by the magnitude of the adsorption bond of substances with water molecules, the formation of unspecified compounds with them, and the distribution of the amount of water according to the bond energy values. Hydrophilicity is primarily determined by the binding energy of the adsorption monolayer, since subsequent layers are much weaker connected to the substance. Hydrophilicity can be expressed by the heat of adsorption of water vapor or the heat of wetting, as well as the work of wetting a unit surface of a substance.

Hydrophobic substances (Greek “hydro” - water, “phobos” - fear) are substances whose molecules’ attraction energy to water molecules is less than the energy of hydrogen bonds of water molecules. Hydrophobic substances include fats, some carbohydrates (starch, glycogen, fiber), nucleic acids, ATP, and most proteins that are insoluble in water.

There are no absolutely hydrophobic (“water-repellent”) substances; even the most hydrophobic - hydrocarbon and fluorocarbon - surfaces adsorb water. Therefore, hydrophobicity is considered as a low degree of hydrophilicity.

G. and g. can be assessed, like the wettability of a surface with water (in air), by the value of the contact angle q: for hydrophilic surfaces<90° (для абсолютно гидрофильных поверхностей q=0); для гидрофобных поверхностей 90°< <180° (напр., для парафина 105°). На трёхфазной границе твёрдого тела с водой и углеводородной жидкостью при <90° (в водной фазе) поверхность олеофобна, т.е. не смачивается маслом, а при =180° - предельно олеофильна.

Hydrophilic substances are substances with polar chemicals. bonds: halides, oxides and their hydrates, carbonates, sulfates, phosphates, silicates and aluminosilicates (clays, glasses), as well as cell membranes. Pure surfaces of metals, carbon, semiconductors, substances consisting of weakly polar molecules, plant leaves, animal skin, and the chitinous cover of insects are hydrophobic. All polar groups that are part of surfactant molecules - surfactants - COOH, -NH2, -SO3Na, etc., are hydrophilic; the hydrocarbon radicals associated with them are hydrophobic.

Amphiphilic substances

Amphiphilicity is a property of molecules of substances (usually organic) that have both hydrophilic and hydrophobic properties. The molecules of amphiphilic compounds are similar to a tadpole: they consist of a long hydrocarbon tail (usually made up of more than ten CH2 groups), ensuring solubility in non-polar media, and a polar head, responsible for hydrophilic properties. Thus, amphiphilic compounds simultaneously “love” both water (that is, they are hydrophilic) and non-polar solvents (they exhibit hydrophobic properties).

Depending on the type of hydrophilic group, amphiphilic compounds bearing a charged cationic or anionic functional group and amphiphilic compounds with an uncharged functional group are distinguished. The vast majority of known organic compounds carry more than one charged functional group. An example of such substances are macromolecular compounds - proteins, lipoproteins, block copolymers, etc. The presence of a tertiary structure in protein molecules, formed as a result of intramolecular interactions of functional groups (polar or nonpolar) with each other, in itself demonstrates the amphiphilic nature of these compounds.

Another example of amphiphilic compounds is the majority of drugs, the molecules of which combine a set of specific functional groups necessary for effective binding to the target receptor.

Amphiphilic compounds play a special role in living nature. No animal or plant can exist without them. It is amphiphilic molecules that make up the cell membrane, which separates a living organism from a hostile external environment. It is these molecules that make up the internal organelles of the cell, participate in the process of its division, and are involved in the exchange of substances with the environment. Amphiphilic molecules serve as food for us and are formed in our bodies, participate in internal regulation and the bile acid cycle. Our body contains more than 10% amphiphilic molecules. That is why synthetic surfactants can be dangerous for living organisms and, for example, can dissolve the cell membrane and lead to its death.

Conclusion

In nature, both types of substances are important. You can find a lot of evidence that hydrophobic substances are found almost everywhere. Thus, clean surfaces of metals, semiconductors, as well as animal skin, plant leaves, and the chitinous cover of insects have similar properties. In turn, hydrophiles are used in the transport of nutrients in the bodies of animals and plants; the end products of metabolism are also excreted using solutions of biological fluids. Nonpolar substances are of great importance in the formation of cell membranes that have selective permeability. That is why such properties play an important role in the course of biological processes. In recent years, scientists have been developing new hydrophobic substances that can be used to protect various materials from wetting and contamination, thus creating even self-cleaning surfaces. Clothing, metal products, building materials, car glass - there are many areas of application. Further study of this topic will lead to the development of multiphobic substances that will become the basis for stain-resistant surfaces. By creating such materials, people will be able to save time, money and resources, and it will also be possible to reduce the degree of environmental pollution from cleaning products. So further developments will benefit everyone.

Bibliography

1. http://fb.ru/article/133638/chto-takoe-gidrofobnyie-veschestva

2.http://www.schoolhels.fi/ school/school_today/ dostigeniya/2012_2013/ nanotexnologiya/page6.htm

3.http://pobiology.rf/ Biological-dictionary/G/265-Hydrophobic-substances

Some people at school were lucky in chemistry lessons not only to write boring tests and calculate molar mass or indicate valency, but also to watch how the teacher conducts experiments. Invariably, as part of the experiment, as if by magic, the liquids in the test tubes changed color unpredictably, and something else could explode or burn beautifully. Perhaps not as impressive, but still interesting are experiments in which hydrophilic and hydrophobic substances are used. By the way, what is this and why are they curious?

Physical properties

In chemistry lessons, when going through another element from the periodic table, as well as all the basic substances, we always talked about their various characteristics. Their physical properties were also touched upon: density under normal conditions, melting and boiling points, hardness, color, electrical conductivity, thermal conductivity and many others. Sometimes there was talk about such characteristics as hydrophobicity or hydrophilicity, but, as a rule, they do not talk about this separately. Meanwhile, this is a rather interesting group of substances that can easily be encountered in everyday life. So it would be useful to learn more about them.

Hydrophobic substances

Examples can easily be taken from life. So, you cannot mix water with oil - everyone knows this. It simply does not dissolve, but remains floating in bubbles or a film on the surface, since its density is lower. But why is this and what other hydrophobic substances exist?

This group usually includes fats, some proteins, and silicones. The name of the substances comes from the Greek words hydor - water and phobos - fear, but this does not mean that the molecules are afraid. They are simply slightly or completely insoluble; they are also called non-polar. Absolute hydrophobicity does not exist; even those substances that, it would seem, do not interact with water at all, still adsorb it, albeit in negligible quantities. In practice, the contact of such a material with H 2 O appears in the form of a film or droplets, or the liquid remains on the surface and takes the shape of a ball, since it has the smallest surface area and provides minimal contact.

Hydrophobic properties are explained by certain substances. This is due to the low rate of attraction to, as it happens, for example, with hydrocarbons.

Hydrophilic substances

The name of this group, as you might guess, also comes from Greek words. But in this case, the second part of philia is love, and this perfectly characterizes the relationship of such substances with water - complete “mutual understanding” and excellent solubility. This group, sometimes called "polar", includes simple alcohols, sugars, amino acids, etc. Accordingly, they have these characteristics because they have a high energy of attraction to the water molecule. Strictly speaking, in general, all substances are hydrophilic to a greater or lesser extent.

Amphiphilicity

Does it happen that hydrophobic substances can simultaneously have hydrophilic properties? It turns out yes! This group of substances is called amphiphilic or amphiphilic. It turns out that the same molecule can have in its structure both soluble - polar and water-repellent - non-polar elements. For example, some proteins, lipids, surfactants, polymers and peptides have such properties. When interacting with water, they form various supramolecular structures: monolayers, liposomes, micelles, bilayer membranes, vesicles, etc. Polar groups are oriented towards the liquid.

Meaning and application in life

In addition to the interaction of water and oil, one can find a lot of evidence that hydrophobic substances are found almost everywhere. Thus, clean surfaces of metals, semiconductors, as well as animal skin, plant leaves, and the chitinous cover of insects have similar properties.

In nature, both types of substances are important. Thus, hydrophiles are used in transport in the organisms of animals and plants; the end products of metabolism are also excreted using solutions of biological fluids. Nonpolar substances are of great importance in the formation of cell membranes, which have That is why such properties play an important role in the course of biological processes.

In recent years, scientists have been developing new hydrophobic substances that can be used to protect various materials from wetting and contamination, thus creating even self-cleaning surfaces. Clothing, metal products, building materials, car glass - there are many areas of application. Further study of this topic will lead to the development of multiphobic substances that will become the basis for stain-resistant surfaces. By creating such materials, people will be able to save time, money and resources, and it will also be possible to reduce the degree of cleaning products. So further developments will benefit everyone.

The term hydrophilicity (derived from the ancient Greek words “water” and “love”) is a characteristic of the intensity of interaction of a substance with water at the molecular level, that is, the ability of a material to intensively absorb moisture, as well as the high wettability of water by the surface of the substance. This concept can be applied to solids, as a property of the surface, and to individual ions, atoms, molecules and their groups.

Hydrophilicity is characterized by the magnitude of the bond between adsorption water molecules and the molecules of a substance; in this case, compounds are formed in which the amount of water is distributed according to the bond energy values.

Hydrophilicity is inherent in substances that have ionic crystal lattices (hydroxides, oxides, sulfates, silicates, clays, phosphates, glasses, etc.) that have polar groups -OH, -NO 2, -COOH, etc. Hydrophilicity and hydrophobicity- special cases of interaction of substances with solvents (lyophilicity, lyophobicity).

Hydrophobicity can be considered as a small degree of hydrophilicity, because the action of intermolecular forces of attraction will always be more or less present between the molecules of any body and water. Hydrophilicity and hydrophobicity can be distinguished by the way a drop of water spreads on a body with a smooth surface. The drop will spread completely on the hydrophilic surface, and partially on the hydrophobic one, while the value of the angle formed between the surface of the wetted material and the drop is influenced by the degree of hydrophobicity of the given body. Hydrophilic substances are substances in which the strength of molecular (ionic, atomic) interactions is quite strong. Hydrophobic are metals that are devoid of oxide films, organic compounds that have hydrocarbon groups in the molecule (waxes, fats, paraffins, some plastics), graphite, sulfur and other substances that have weak interactions at the intermolecular level.

The concepts of hydrophilicity and hydrophobicity are applied both in relation to bodies and their surfaces, and in relation to individual molecules or individual parts of molecules. For example, the molecules of surface active substances contain polar (hydrophilic) and hydrocarbon (hydrophobic) compounds. The hydrophilicity of the surface part of the body can change dramatically due to the adsorption of such substances.

Hydrophilization is the process of increasing hydrophilicity, and hydrophobization is the process of decreasing it. These phenomena are of great importance in the cosmetics industry, in textile technology for hydrophilization of fabrics (fibers) to improve the quality of washing, bleaching, dyeing, etc.

Hydrophilicity in cosmetics

The perfumery and cosmetics industry produces hydrophilic creams and gels that protect the skin from impurities that are not soluble in water. Such products contain hydrophilic components that form a film that prevents the penetration of water-insoluble pollutants into the surface layer of the skin.

Hydrophilic creams are made from an emulsion that is stabilized with suitable emulsifiers or with a water-oil-water or oil-water base. In addition, these include dispersed colloidal systems in which hydrophilic surfactant components are stabilized and consisting of water-dispersed or water-glycol mixed solvents of higher fatty acids or alcohols.

Hydrogels (hydrophilic gels) are prepared from bases consisting of water, a mixed non-aqueous or hydrophilic solvent (ethyl alcohol, propylene glycol, glycerin) and a hydrophilic gelling agent (cellulose derivatives, carbomers).

Hydrophilic properties of creams and gels:

· quickly and well absorbed;

· nourish the skin;

· after their use there is no feeling of greasyness;

· cleanse the skin;

· have a strengthening effect on the skin;

· reduce the effect of negative environmental factors;

Help the skin maintain its natural ability to regenerate.

Hydrophilic creams and gels are designed to protect the skin when working with water-immiscible oils, fuel oil, petroleum, paints, resins, graphite, soot, organic solvents, cooling and lubricating solutions, construction foam and numerous other mildly aggressive substances. They are also indispensable when repairing a car, renovating an apartment, during construction, in the country when working with fertilizers and soil.

The KorolevPharm company produces various types of perfumery and cosmetic products, including hydrophilic and hydrophobic creams. The company is a contract manufacturer and carries out all stages of production: development of recipes, certification, launching production, serial production of products. The production site is equipped with modern equipment.

The enterprise is certified for compliance with the requirements

HYDROPHILICITY AND HYDROPHOBICITY (from the Greek hydor - water and philia - love or phobos - fear, fear * a. wetting ability hydrophoby; n. Hydrophilie und Hydrophobie; f. hydrophilite et hydrophobie; i. hidrofilia e hidrofobia) - concepts characterizing affinity substances or bodies formed by them; this affinity is due to the forces of intermolecular interaction. The concepts of hydrophilicity and hydrophobicity can apply equally to a substance, to the surface of a body, and to a thin layer (in the limit, one molecule thick) at the interface between phases (bodies). Hydrophilicity and hydrophobicity are a special case of lyophilicity and lyophobicity - characteristics of the molecular interaction of substances with various liquids.

A general measure of hydrophilicity is the binding energy of water molecules to the surface of the body; it can be determined by the heat of wetting if the substance of a given body is insoluble. Hydrophobicity is considered as a low degree of hydrophilicity, because Between the molecules of water and any body, intermolecular forces of attraction always act to a greater or lesser extent. Hydrophilicity and hydrophobicity can be assessed by the spreading of a drop of water on a smooth body surface (Fig.); characterized by the contact angle; on a hydrophilic surface the drop spreads completely, on a hydrophobic surface it spreads partially, and the angle between the surfaces of the drop and the wetted body depends on how hydrophobic the body is.

All bodies in which the intensity of molecular (atomic, ionic) interactions is sufficiently high are hydrophilic. Hydrophilicity is especially pronounced with ionic crystal lattices (for example, etc.), as well as silicate glasses. Metals that lack oxide films, organic compounds with a predominance of hydrocarbon groups in the molecule (for example, paraffins, fats, waxes, some plastics), and other substances with weak intermolecular interactions are hydrophobic.

The concepts of hydrophilicity and hydrophobicity apply not only to bodies or their surfaces, but also to single molecules or individual parts of molecules. Thus, in the molecules of surfactants, hydrophilic (polar) and hydrophobic (hydrocarbon) groups are distinguished. The hydrophilicity of the body surface can change dramatically as a result of the adsorption of such substances. An increase in hydrophilicity is called hydrophilization, and a decrease is called hydrophobization. Both phenomena play an important role in the method. Hydrophilization results in selective gangue minerals. For these purposes, organic (starch, dextrin, etc.) and inorganic (liquid glass, sodium cyanide, etc.) reagents are used. Hydrophobization is caused by the addition of special collecting reagents. See also .