Colloidal Dispersion

Question 1

a bounded space or an exact
quantity of a material

Answer 1

system

Question 2

consists of at least two phases with one or more dispersed phase (internal) contained in a single continuous (external) phase

Answer 2

dispersion

Question 3

a distinct homogenous part of a system

Answer 3

phase

Question 4

internal phase?

Answer 4

dispersed phase

Question 5

external or continuous phase?

Answer 5

dispersion medium

Question 6

• diameter of particles < 1 nm
• A.k.a. True Solutions (one-phase)

Answer 6

molecular dispersion

Question 7

• diameter of particles 1 to 500 nm
• e.g. gelatin mixture, milk

Answer 7

colloidal dispersion

Question 8

• diameter of particles > 500 nm
• Ex. Emulsions and suspensions

Answer 8

coarse dispersion

Question 9

particle size of colloidal dispersions?

Answer 9

between 1 nm to 500 nm

Question 10

can colloidal dispersions be resolved by ordinary microscope?

Answer 10

no

Question 11

what microscopes can colloidal dispersions be seen under?

Answer 11

electron microscope

Question 12

can colloidal dispersions pass through filter paper?

Answer 12

yes

Question 13

can colloidal dispersions pass through semipermeable membranes?

Answer 13

no

Question 14

what is a colloidal dispersion’s diffusion rate?

Answer 14

slow

Question 15

examples of colloidal dispersions

Answer 15

jelly, polymers, milk, paint, cheese

Question 16

surface area per unit W or V

Answer 16

specific surface

Question 17

• possess large specific surface
  gold sol: Red -> Blue (larger)
• color related to particle size
  Sb and As trisulfides: Yellow -> Red (larger)

Answer 17

colloidal particles

Question 18

colloidal form of Pt

Answer 18

platinum black

Question 19

*More extended
→ greater Specific surface
→ greater interaction between
dispersed phase and dispersion medium

Answer 19

shape of colloidal particles

Question 20

• Scattering of light by colloidal particles
• widely used for determining MW of colloids

Answer 20

Faraday-Tyndall Effect

Question 21

• Used to observe the size, shape, and
  structure of colloidal particles
• Has higher resolution power than
  optical microscope

Answer 21

Electron microscope

Question 22

brownian movement, diffusion, osmotic pressure, sedimentation (settling), viscosity

Answer 22

kinetic properties of colloids

Question 23

• random movement of colloidal particles
• velocity increases with decreasing particle size

Answer 23

Brownian Movement

Question 24

• spontaneous movement from high to low
  concentration until uniform system is achieved
• a direct results of Brownian movement

Answer 24

Diffusion

Question 25

diffusion can be expressed through?

Answer 25

Fick's First Law

Question 26

can be described by van’t Hoff equation

Answer 26

Osmotic Pressure

Question 27

Van't Hoff Equation:

Answer 27

𝝅=𝒄𝑹𝑻

Question 28

- velocity of sedimentation is given by Stoke’s law

Answer 28

Sedimentation (Settling)

Question 29

- resistance to flow of a system under applied stress - more viscous →greater force to make it flow - affected by shape of particles e.g. SPHERICAL →less viscous LINEAR →more viscous

Answer 29

Viscosity

Question 30

pharmaceutical applications of colloids?

Answer 30

1.) hydrogels 2.) microparticles 3.) liposomes 4.) micelles

Question 31

- a colloidal gel in which water is DM - used for

Answer 31

hydrogels

Question 32

uses for hydrogels

Answer 32

a) wound healing b) scaffolds in tissue engineering c) sustained-release of drugs

Question 33

- developed as carriers for vaccines and anticancer drugs - increase efficiency of drug delivery, release and targeting

Answer 33

microparticles

Question 34

size of microparticles

Answer 34

(0.2 - 5 um)

Question 35

contains polymer 1 of microparticles

Answer 35

outer shell

Question 36

contains polymer 2 of dispersed drug

Answer 36

core

Question 37

consists of an outer membrane and an inner liquid core

Answer 37

liposomes

Question 38

forms liposomes

Answer 38

phospholipids

Question 39

lipophilic compounds ->

Answer 39

lipophilic membrane

Question 40

hydrophilic compounds ->

Answer 40

hydrophilic core

Question 41

- similar to liposomes but do not have inner liquid compartment - used for delivery of hydrophobic pharmaceuticals

Answer 41

micelles