6 Concluding Remarks
In recent years, strategies for the synthesis of macroporous gels have been continually optimized and the concept of cryogelation has become increasingly important
for the synthesis of such smart materials. Cryogelation is a simple strategy that
allows the preparation of macroporous gels with high toughness and superfast
responsivity. Although discovered over 30 years ago, cryogels have attracted
intense attention only in the last 10 years due to their extraordinary properties.
Cryogels are very tough gels that can withstandhigh levels of deformation, such as
elongation and torsion, and can be squeezed almost completely without any crack
propagation. The cryogelation temperature, the freezing rate of the reaction solutions, the type and concentration of the gel precursors, and the solvent are the main
synthesis parameters determining the properties of the resultant cryogel. Some
novel cryogels presented in this chapter (including DNA, silk fibroin, PAAc, and
rubber cryogels) show that cryogelation technology opens new application areas for
macroporous materials. Current research in the field of macroporous gels is focused
on tailor-made design of the pore structure. The polymerization and/or crosslinking
reactions at subzero temperatures that lead to cryogels are multicomponent systems
composed of a polymer network, soluble polymers, and low molecular weight
GASOLINE
Sorbed pollutant (g/g sorbent)
10
20
30
40
FUEL OIL
DIESEL
Number of cycles
4
8
12
16
20
CRUDE OIL
Number of cycles
4
8
12
16
20
0
10
20
30
40
OLIVE OIL
Number of cycles
4
8
12
16
20
PIB2 - 5 %
CBR - 5 %
SBR - 5 %
PIB1 - 5 %
SBR - 2.5 %
CBR - 2.5 %
Fig. 26 Continuous extraction capacities of the cryogels for various pollutants as a function of the
number of cycles. S 2 Cl 2 ¼ 6 %. C R ¼ 5 %: PIB1 (inverted triangle), PIB2 ( filled triangle), CBR
( filled square), SBR (open circle). C R ¼ 2.5 %: CBR (open square) and SBR (open circle). (From
[55] with permission from Elsevier)
152
O. Okay and V.I. Lozinsky
In recent years, strategies for the synthesis of macroporous gels have been continually optimized and the concept of cryogelation has become increasingly important
for the synthesis of such smart materials. Cryogelation is a simple strategy that
allows the preparation of macroporous gels with high toughness and superfast
responsivity. Although discovered over 30 years ago, cryogels have attracted
intense attention only in the last 10 years due to their extraordinary properties.
Cryogels are very tough gels that can withstandhigh levels of deformation, such as
elongation and torsion, and can be squeezed almost completely without any crack
propagation. The cryogelation temperature, the freezing rate of the reaction solutions, the type and concentration of the gel precursors, and the solvent are the main
synthesis parameters determining the properties of the resultant cryogel. Some
novel cryogels presented in this chapter (including DNA, silk fibroin, PAAc, and
rubber cryogels) show that cryogelation technology opens new application areas for
macroporous materials. Current research in the field of macroporous gels is focused
on tailor-made design of the pore structure. The polymerization and/or crosslinking
reactions at subzero temperatures that lead to cryogels are multicomponent systems
composed of a polymer network, soluble polymers, and low molecular weight
GASOLINE
Sorbed pollutant (g/g sorbent)
10
20
30
40
FUEL OIL
DIESEL
Number of cycles
4
8
12
16
20
CRUDE OIL
Number of cycles
4
8
12
16
20
0
10
20
30
40
OLIVE OIL
Number of cycles
4
8
12
16
20
PIB2 - 5 %
CBR - 5 %
SBR - 5 %
PIB1 - 5 %
SBR - 2.5 %
CBR - 2.5 %
Fig. 26 Continuous extraction capacities of the cryogels for various pollutants as a function of the
number of cycles. S 2 Cl 2 ¼ 6 %. C R ¼ 5 %: PIB1 (inverted triangle), PIB2 ( filled triangle), CBR
( filled square), SBR (open circle). C R ¼ 2.5 %: CBR (open square) and SBR (open circle). (From
[55] with permission from Elsevier)
152
O. Okay and V.I. Lozinsky