Abstract Polymeric gels belong to the most important class of functional polymers in modern biotechnology. They are useful materials for drug delivery systems,
artificial organs, separation operations in biotechnology, processing of agricultural
products, on–off switches, sensors, and actuators. Despite this fact and considerable
research in this field, the design and control of gel-based devices still present some
problems due to the their poor mechanical performance and slow rate of response to
external stimuli. Cryogelation techniques discovered more than 30 years ago
overcome these limitations by producing macroporous gels with high toughness
and superfast responsivity. This chapter discusses how and why the properties of
gels significantly alter upon transition from homogeneous gelation to a cryogelation
regime. The formation and structure–property relationships of cryogels starting
from monovinyl–divinyl monomers, as well as from linear polymer chains, are
reviewed using examples from the recent literature. Some novel cryogels with a
wide range of tunable properties and their applications are also presented in detail.
These include DNA cryogels for the removal of carcinogens from aqueous environments, silk fibroin cryogels as mechanically strong scaffolds for bone tissue
engineering applications, poly(acrylic acid) cryogels as self-oscillation systems,
and rubber cryogels as reusable oil sorbent for the removal of oil spill from
seawater.
Keywords Cryogels • Porosity formation • Gelation • Elasticity • Swelling
Abbreviations
α
Dissociation degree
χ
Polymer–solvent interaction parameter
λ
Deformation ratio
ν e
Effective crosslink density
σ
Nominal stress
σ comp
Compressive stress
σ p
Critical stress corresponding to the plateau regime
AAc
Acrylic acid
AAm
Acrylamide
AMPS
2-Acrylamido-2-methylpropane sulfonic acid sodium salt
APS
Ammonium persulfate
BAAm
N,N-methylene(bis)acrylamide
BDDE
1,4-Butanediol diglycidyl ether
C
Monomer concentration in the unfrozen zones
CBR
cis-Polybutadiene
C o
Initial concentration of the monomeric or the polymeric precursors
C R
Rubber concentration
C SF
Fibroin concentration
DMA
N,N-Dimethylacrylamide
104
O. Okay and V.I. Lozinsky
artificial organs, separation operations in biotechnology, processing of agricultural
products, on–off switches, sensors, and actuators. Despite this fact and considerable
research in this field, the design and control of gel-based devices still present some
problems due to the their poor mechanical performance and slow rate of response to
external stimuli. Cryogelation techniques discovered more than 30 years ago
overcome these limitations by producing macroporous gels with high toughness
and superfast responsivity. This chapter discusses how and why the properties of
gels significantly alter upon transition from homogeneous gelation to a cryogelation
regime. The formation and structure–property relationships of cryogels starting
from monovinyl–divinyl monomers, as well as from linear polymer chains, are
reviewed using examples from the recent literature. Some novel cryogels with a
wide range of tunable properties and their applications are also presented in detail.
These include DNA cryogels for the removal of carcinogens from aqueous environments, silk fibroin cryogels as mechanically strong scaffolds for bone tissue
engineering applications, poly(acrylic acid) cryogels as self-oscillation systems,
and rubber cryogels as reusable oil sorbent for the removal of oil spill from
seawater.
Keywords Cryogels • Porosity formation • Gelation • Elasticity • Swelling
Abbreviations
α
Dissociation degree
χ
Polymer–solvent interaction parameter
λ
Deformation ratio
ν e
Effective crosslink density
σ
Nominal stress
σ comp
Compressive stress
σ p
Critical stress corresponding to the plateau regime
AAc
Acrylic acid
AAm
Acrylamide
AMPS
2-Acrylamido-2-methylpropane sulfonic acid sodium salt
APS
Ammonium persulfate
BAAm
N,N-methylene(bis)acrylamide
BDDE
1,4-Butanediol diglycidyl ether
C
Monomer concentration in the unfrozen zones
CBR
cis-Polybutadiene
C o
Initial concentration of the monomeric or the polymeric precursors
C R
Rubber concentration
C SF
Fibroin concentration
DMA
N,N-Dimethylacrylamide
104
O. Okay and V.I. Lozinsky