The key difference between hydrogel and hydrocolloid is that hydrogel does not dissolve in water, whereas hydrocolloid forms a gel when mixing with water.
Hydrogel is a crosslinked hydrophilic polymer that cannot dissolve in water. Hydrocolloid is a substance that forms a gel in water.
CONTENTS
1. Overview and Key Difference
2. What is a Hydrogel
3. What is a Hydrocolloid
4. Hydrogel vs Hydrocolloid in Tabular Form
5. Summary – Hydrogel vs Hydrocolloid
What is a Hydrogel?
Hydrogel is a crosslinked hydrophilic polymer that cannot dissolve in water. Although hydrogels are highly absorbent, these materials also tend to maintain a well-defined structure. We can prepare these materials using different polymers that can be either natural or synthetic. Among them, the natural sources for hydrogel production include hyaluronic acid, chitosan, heparin, alginate, and fibrin, while the synthetic sources include polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, acrylate polymers and their copolymers.
Figure 01: Gelatin is a Type of Hydrogel
There are many different uses of hydrogel: manufacture of contact lenses, scaffolds in tissue engineering, useful for cell cultures, as drug carriers, useful as biosensors, manufacture of disposable diapers, water gel explosives, breast implants, etc.
What is a Hydrocolloid?
Hydrocolloid is a substance that forms a gel in water. We often use this material as a hydrocolloid dressing, which is an opaque or transparent dressing for wounds. These types of dressings are biodegradable, breathable and can adhere to the skin, which ensures that there is no need for separate taping.
Hydrocolloid is a colloid system, where the colloid particles are hydrophilic polymer materials that are dispersed in water. There are colloid particles that spread throughout the water, and the amount of colloid particles depends on the quantity of water available to occur in different phases such as gel or sol. Moreover, a hydrocolloid can be either reversible or irreversible. For example, agar is a reversible hydrocolloid because it can exist in a gel and solid-state, which can alternate between phases upon the elimination of heat.
Typically, most hydrocolloids form from natural polysaccharide sources. For instance, agar-agar mixture, gelatin desserts, xanthan gum, Arabic gum, guar gum, locust bean gum, cellulose derivatives, etc., are forms of hydrocolloids.
What is the Difference Between Hydrogel and Hydrocolloid?
Hydrogel is a crosslinked hydrophilic polymer that cannot dissolve in water. Hydrocolloid is a substance that forms a gel in water. So, the key difference between hydrogel and hydrocolloid is that hydrogel does not dissolve in water, whereas hydrocolloid forms a gel when mixing with water. Moreover, hydrogels exist in the semi-solid (gel) phase, while hydrocolloid substances are mostly solids that can form a gel when mixing with water.
Hydrogel is used in the manufacture of contact lenses, scaffolds in tissue engineering, for cell cultures, as drug carriers, as biosensors, in the manufacture of disposable diapers, water gel explosives, breast implants, etc. Hydrocolloid, on the other hand, is used in increasing food consistency, improving gelling effect, controlling moisture, texture, flavour, and shelf life, etc. Hydrogels can be from either natural or synthetic sources; natural sources include such as hyaluronic acid, chitosan, heparin, alginate, and fibrin. Meanwhile, synthetic sources include polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, acrylate polymers and copolymers thereof. On the other hand, hydrocolloids are mostly derived from natural polysaccharides such as agar-agar mixture, gelatin desserts, xanthan gum, Arabic gum, guar gum, locust bean gum, cellulose derivatives, etc.
The following table summarizes the difference between hydrogel and hydrocolloid.
Summary – Hydrogel vs Hydrocolloid
Hydrogel is a crosslinked hydrophilic polymer that cannot dissolve in water. Hydrocolloid is a substance that forms a gel in water. The key difference between hydrogel and hydrocolloid is that hydrogel does not dissolve in water, whereas hydrocolloid forms a gel when mixing with water.
Reference:
1. “What Are Hydrocolloids?” Edinformatics.
Image Courtesy:
1. “Gelatine” By Danielle dk – Own work (CC BY-SA 3.0) via Commons Wikimedia