Properties of Gels in Chemistry

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What is the primary reason why gels behave like solids despite being mostly liquid by mass?

The formation of a three-dimensional cross-linked network within the liquid (correct)
The presence of a solid medium within the liquid
The presence of a covalent polymer network
The dispersion of molecules of a liquid within a solid medium

Who is credited with coining the term 'gel'?

A group of scientists who studied colloidal networks
An unknown 19th century chemist
Thomas Graham (correct)
A member of the International Union of Pure and Applied Chemistry

What is the process of forming a gel called?

Colloidization
Cross-linking
Gelation (correct)
Polymerization

According to the IUPAC definition, what is a characteristic of a gel?

A gel has a finite, usually rather small, yield stress (A) Signup and view all the answers

What type of bonds can cause physical aggregation of polymer chains in a gel?

Hydrogen bonds (A) Signup and view all the answers

What is a 'thermoreversible gel'?

A gel that has regions of local order that are thermally reversible (A) Signup and view all the answers

What is the primary reason why polyionic polymers contribute more to viscosity in their stretched state?

Because the ionic charges prevent the formation of tightly coiled polymer chains (D) Signup and view all the answers

What is the characteristic of a colloidal gel that leads to the rise of elastic behavior?

The formation of a percolated network of particles (D) Signup and view all the answers

What happens to the particles in a colloidal gel during the aging phase?

They slowly rearrange to form thicker strands (D) Signup and view all the answers

What is the primary characteristic of a gel that is similar to that of its constituent liquids?

Density (C) Signup and view all the answers

What is the result of a colloidal gel being subjected to external fields such as gravity?

It collapses and separates (C) Signup and view all the answers

What is the behavior of colloidal gels at low amplitudes?

Linear response rheology (C) Signup and view all the answers

What is the primary characteristic of hydrogels that allows them to maintain their structural integrity in high water concentrations?

The presence of cross-links between polymer chains (B) Signup and view all the answers

What is the primary advantage of hydrogels as 'smart materials'?

Their ability to encapsulate and release chemical compounds in response to external stimuli (B) Signup and view all the answers

What is the primary difference between hydrogels and organogels?

The type of liquid entrapped in the cross-linked network (A) Signup and view all the answers

What is the significance of the term 'hydrogel' in the context of materials science?

It refers to a type of polymeric network that can absorb high amounts of water (B) Signup and view all the answers

What is the primary application of chemomechanical polymers?

As actuators or sensors (B) Signup and view all the answers

What is the characteristic of hydrogels that allows them to mimic natural tissue?

Their significant water content (D) Signup and view all the answers

What is the primary factor influencing the stimuli-responsive characteristic of a biomaterial?

The sensitivity of the biomaterial to the stimuli factor (C) Signup and view all the answers

What is the purpose of implementing intelligent biomaterials in biological systems?

To enhance tissue regeneration (C) Signup and view all the answers

What is the result of programming hydrogels with specific molecules?

Enhancement of biomaterial functionalities (B) Signup and view all the answers

What is the primary advantage of using click-based orthogonal approaches in hydrogels?

Simplicity, convenience, and productivity (C) Signup and view all the answers

What is the advantage of using biomaterials sensitive to external stimuli in tissue regeneration?

It allows for precise control over biomaterial properties (C) Signup and view all the answers

What is the result of the reversible bridge via physical crosslinking in hydrogels?

Structural changes in response to external stimuli (B) Signup and view all the answers

What is the effect of surface functionalization on intelligent hydrogels?

It changes the macromolecular structure of the hydrogels (D) Signup and view all the answers

What is the main purpose of using reversible crosslinking in hydrogels?

To constitute self-healing characteristics (C) Signup and view all the answers

What is the goal of using biomimetic approaches in biomaterials?

To ensure biocompatibility (B) Signup and view all the answers

What are the two viable options for fabricating intelligent biomaterials?

Nature-inspired strategies and click-based orthogonal methods (D) Signup and view all the answers

What is the characteristic of intelligent biomaterials mentioned in the passage?

Shape memory (D) Signup and view all the answers

What is the purpose of injectable shape-memory hydrogels?

To deliver drugs to viable tissues through a minimally invasive treatment strategy (D) Signup and view all the answers