Hydrophilic vs Hydrophobic: Difference and Comparison

The term Hydro means water. Therefore, it can be said that the study of hydrophilic and hydrophobic molecules deals with the solubility and properties of these materials as they link to and interact with water.

The two terms may seem the same, but they are opposites.

The word ‘phobic’ derives from ‘phobia,’ which means fear. Hence the term hydrophobic means fear of water.

The term ‘philic’ derives from the word ‘philia,’ which means friendship. Hence the term hydrophilic means loving water.

Thus, hydrophilic materials are those that link well with water, whereas hydrophobic molecules are those that do not interact well with water. The difference between hydrophilic and hydrophobic materials is drawn by observing their reaction towards water, either attraction to water or repellency of water.

For example, we can see that there are a few solubles that get absorbed in water, while there are few that do not. Salt can get dissolved in water easily, whereas powdered makeup cannot. Salt 

On the other hand, it is not absorbed in oil, which is a hydrophobic liquid, whereas powdered or crushed makeup can dissolve in oil.

Thus, it can be said that powdered makeup is hydrophobic, whereas salt is hydrophilic.

Key Takeaways

1. Hydrophilic substances are attracted to water molecules and can dissolve or disperse in water; hydrophobic substances repel water and are not soluble in water.
2. Hydrophilic substances have polar or charged groups that can form hydrogen bonds with water; hydrophobic substances have non-polar molecules that cannot form hydrogen bonds with water.
3. Hydrophilic substances are used in applications where water solubility is desired, such as in detergents and pharmaceuticals; hydrophobic substances are used in waterproofing and oil-repelling applications, such as in raincoats and non-stick pans.

Hydrophilic vs. Hydrophobic

Hydrophilic is a term that refers to substances or materials that can easily get along with water in case of chemical reactions. Salt is hydrophilic as it can easily dissolve in water. Hydrophobic refers to the items that do not react with water and repel water molecules when reacting with them.

Comparison Table

Parameter of Comparison	Hydrophilic	Hydrophobic
Meaning	It means water-loving or having a strong inclination towards water.	It means being resistant to water or avoiding water.
Molecules	The hydrophilic molecules are called hydrophiles.	The hydrophobic molecules are called hydrophobes.
Interaction with water	The hydrophilic molecules attract water.	The hydrophobic molecules repel water.
Polarity	Hydrophilic molecules are polar.	Hydrophobes are non polar.
Reaction	Dissolving the hydrophilic molecules in water is an exothermic reaction.	Dissolving the hydrophilic molecules in water is an endothermic reaction.

What is Hydrophilic?

Hydro means water. ‘philic’ derives from ‘philia,’ which means friendship. Thus the word hydrophilic means loving water.

Hydrophilic molecules that are known as hydrophiles are molecules that attract water. Hydrophilic molecules are polar.

Application of Hydrophilic molecules:

The hydrophilic molecules are largely used in several fields, such as chemistry, physics, food, engineering, paint, drug delivery, paper, textiles, biomedical, pharmaceuticals, water treatment, constructions, coatings, adhesives, thickeners, film formers, gallants, stabilizers, dispersing and suspending agents, humectants, flocculants, personal care, lubricants and binders, detergents, mineral processing, building products, and oil field products.

Examples of hydrophilic substances:

There are a large number of hydrophilic substances, such as starch, salt, sugar, keratin, protein, cotton, cellulose, wool, silica, alcohols, polyethylene glycol ethers, polyvinyl alcohol, gelatin, inulin, guar gum, albumin, chitosan, xanthan gum, agarose, pectin, agar, dextran, algin, carrageenan and so on.

What is Hydrophobic?

The word Hydro means water. The term ‘phobic’ derives from the word ‘phobia,’ which means fear. Hence the term hydrophobic means fear of water. 

Hydrophobic molecules that are known as hydrophobes, are molecules that repel water.  Hydrophobes are non polar in nature.

Application of Hydrophobic molecules:

Hydrophobic interactions are important in many fields, such as oil-water separation, self-cleaning, antibacterial, corrosion resistance, anti-icing, protein folding, chemical separation process, oil spill management, non-polar elements separation from polar elements, etc.

Examples of Hydrophobic substances:

A large number of hydrophobic substances can be seen in both the industrial and the domestic sectors. Greasy compounds, fats, oils, alkanes, and most organic compounds are examples of hydrophobic substances.

Other examples of hydrophobic substances include hydrophobicity in plants and animals. Many plants are hydrophobic, which means there is a presence of hydrophobic coatings on the leaf’s surface. 

Hydrophobicity can also be seen in birds, and it plays a vital role. The hydrophobicity in the feathers and bodies does not allow water penetration in the bodies and thus helps to avoid weight gains and helps them in flying smoothly.

Main Differences Between Hydrophilic and Hydrophobic

1. Hydrophilic means having harmony with water or water-loving. On the other hand, Hydrophobic means resistance to wetting.
2. Hydrophiles are hydrophilic molecules, whereas hydrophobes are hydrophobic molecules.
3. Hydrophiles get dissolved or absorbed in water. Hydrophobes are not dissolved in water but only absorbed in oil-based substances.
4. Hydrophilic molecules are ionic and polar, while Hydrophobic molecules are nonpolar.
5. When the hydrophilic molecules are added to water, the entropy gets increased. When the hydrophobic molecules are added to water, the entropy gets decreased.

References

1. https://pubs.rsc.org/en/content/articlehtml/2001/gc/b103275p
2. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.186101