The solvent-loving colloids or such colloids which show less or distinct affinity towards dispersion medium is known as Lyophilic colloids. The solvent-hating colloids or such colloids which do not have any attraction towards dispersion medium is known as Lyophobic colloids.
The colloidal state is said when the particle size is between 1 to 100 nm. When the particle size is less than 1nm it is in the true solution, while when the particle size is more than 100 nm, the matter exists in the visible precipitate. Therefore, the colloidal state is the intermediate between the true solution and the precipitate.
The colloidal state exists as heterogeneous and has two phases; the Dispersed phase and the Dispersion phase. The dispersed phase is the internal phase of the sols, which constitutes the colloidal particles, while the dispersion medium is the external phase, which is the medium in which the colloidal particles are suspended.
Based on the affinity of the dispersion phase to that of the dispersion medium, the colloids are differentiated into two types: Lyophilic and Lyophobic colloids. Thomas Graham is regarded as the ‘father of colloidal chemistry.
In this context, we will discuss the differences between the lyophilic and lyophobic colloids, with the description of them and their examples as well as biological importance.
Content: Lyophilic Vs Lyophobic Colloids
|Basis for Comparison||Lyophilic Colloids||Lyophobic Colloids|
|Meaning ||Lyophilic colloids are said as the solvent loving or liquid loving colloids. ||Lyophobic is known as the solvent hating or liquid hating colloids.|
|Examples||Sols of organics substances such as proteins, starch, gum and gelatins.||Sols of inorganic substances such as Ferric Hydroxide, Aluminium hydroxide, Platinum and Arsenic.|
|Sols Preparation||Lyophilic sols are easily prepared by mixing liquids and colloids. ||Lyophobic sols are prepared by adding stabilizers along with mechanical agitation.|
|Precipitation ||In lyophilic sol, precipitation is the reversible process.||In the lyophobic sol precipitation is the irreversible process.|
|Force of attraction||There is a strong force of attraction between liquids and the colloids.||There is no or very less force of attraction between liquids and the colloids.|
|Stability ||Thermodynamically stable.||Thermodynamically unstable.|
|Hydrophilic/hydrophobic colloids||Lyophilic colloids are known as hydrophilic colloids when water is in the dispersion medium.||Lyophobic colloids are said as hydrophobic colloids when water is used as the dispersion medium.|
|Charge||The charge of the particles in the lyophilic sol depends on the pH of the medium.||The charge of the particles is the same in the lyophobic sol.|
|Viscosity||Lyophilic sol is highly viscous.||Lyophobic sol carries the same viscosity as the solvent.|
|Surface Tension||The surface tension of the lyophilic sols is less than to that of the dispersion medium.||Surface tension is the same as that of the dispersion medium.
|Tyndall effects||Lyophilic sols show less Tyndall effects.||Lyophobic sols show strong Tyndall effects.
|These sols show high colligative properties.||These sols have low colligative properties.
Definition of Lyophilic Colloids
These colloids are said to the solvent-loving, as these colloids have a distinct attraction towards dispersion medium. When lyophilic colloids are mixed with the liquids, the strong force of attraction arises between liquid and colloidal particles which results in the formation of such a stable solution.
Proteins, gums, and starch are examples such as sols. Lyophilic sols can be directly prepared by mixing liquid and colloid, and therefore these sols are stable and do not get easily precipitated. But by adding electrolytes in large quantities, the particles can be precipitated. However the quantity of liquid is again increased in the solution, the lyophilic properties can regain the sol, and this is said as the reversible nature of the lyophilic colloids.
In the electric field, the particles of the sols move in a definite direction, and it depends on the charge, cathode or anode or may not move also.
Definition of Lyophobic Colloids
Lyophobic colloids are said as the solvent-hating, as these colloids do not have any attraction towards the dispersion medium. When the lyophobic colloids are mixed with the liquid, the force of attraction which arises is very weak between the liquid and the colloidal particles. The lyophobic sols are not easy to prepare and need special techniques.
The water-hating colloids are said to be the hydrophobic colloids, and the dispersion is said to the hydrophobic sol. The lyophobic sols are less stable. These are irreversible sols by nature, as adding a small number of electrolytes may cause particles to precipitate and do not regain their original state.
Key Differences Between Lyophilic and Lyophobic Colloids
Following are the essential points which exhibit the differences between the Lyophilic and Lyophobic Colloids:
- Lyophilic colloids are known for their solvent loving or liquid loving colloids, while Lyophobic colloids are known as the solvent hating or liquid hating colloids.
- Examples of lyophilic colloids are sols of organics substances such as proteins, starch, gum, and gelatins, whereas sols of inorganic substances such as Ferric Hydroxide, Aluminium hydroxide, Platinum and Arsenic.
- Sols are easily prepared in the case of lyophilic colloids by mixing liquids and colloids, though in the case of lyophobic colloids adding stabilizers with mechanical agitation is needed.
- In lyophilic sol, precipitation is the reversible process, and the lyophilic sols are thermodynamically stable, but in lyophobic sol precipitation is the irreversible process, and these are thermodynamically unstable.
- There is a strong force of attraction between liquids and the colloids in the lyophilic sols, though it is weak or no force of attraction between liquids and colloids in the lyophobic sols.
- Lyophilic colloids are known as hydrophilic colloids when water is in the dispersion medium, whereas Lyophobic colloids are said as hydrophobic colloids when water is used as the dispersion medium.
- Lyophilic sol is highly viscous, as compared to the lyophobic sol which carries the same viscosity as the solvent.
- The surface tension of the lyophilic sols is less than to that of the dispersion medium, and Surface tension is the same as that of the dispersion medium of lyophobic sols.
- Lyophilic sols show less Tyndall effects and high colligative properties, but the lyophobic sols show strong Tyndall effect and low colligative properties.
Biological Importance of colloids
Given below are the critical points on the biological importance of colloids:
- Fat digestion and absorption: Colloids supports in the formation of emulsions, fat digestions, and absorption of the intestinal tract.
- Formation of urine: The filtration of urine is based on this principle.
- Biological fluids as colloids: It includes milk, blood, and cerebrospinal fluid.
- Biological compounds as colloidal particles: The colloidal state exists in complex lipids and polysaccharides, high molecular weight proteins.
In the given article we came to know about the colloidal solution and their properties, and how they variate from each other. We also came to the biological importance of such colloids.