introduction of hydrophobic segments into the hydrophilic chains protects the
quadruple H-bonding between UPy units. Physical hydrogels with 80 wt% water
and containing UPy units in the backbone of segmented amphiphilic polymers
having hydrophilic poly(ethylene glycol) (PEG) sustain up to ~1 MPa stresses
(Fig. 3b) [36]. Bulk images of the hydrogels show existence of UPy-UPy dimers
serving as physical cross-links which are surrounded by segregated hydrophobic
regions dispersed within the PEG matrix. H-bonded hydrogels via UPy units were
Fig. 3 (a) Structure of DAT groups and their H-bonding sites shown by the dashed lines. From [33]
with permission from the Royal Society of Chemistry. (b) UPy unit in a segmented amphiphilic
polymer chain (upper panel) and quadruple H-bonds between UPys forming semicrystalline
polymer morphology in dry state and reversible transition to hydrogel after swelling in water
(bottom panel). From [36] with permission from the American Chemical Society
28
O. Okay
quadruple H-bonding between UPy units. Physical hydrogels with 80 wt% water
and containing UPy units in the backbone of segmented amphiphilic polymers
having hydrophilic poly(ethylene glycol) (PEG) sustain up to ~1 MPa stresses
(Fig. 3b) [36]. Bulk images of the hydrogels show existence of UPy-UPy dimers
serving as physical cross-links which are surrounded by segregated hydrophobic
regions dispersed within the PEG matrix. H-bonded hydrogels via UPy units were
Fig. 3 (a) Structure of DAT groups and their H-bonding sites shown by the dashed lines. From [33]
with permission from the Royal Society of Chemistry. (b) UPy unit in a segmented amphiphilic
polymer chain (upper panel) and quadruple H-bonds between UPys forming semicrystalline
polymer morphology in dry state and reversible transition to hydrogel after swelling in water
(bottom panel). From [36] with permission from the American Chemical Society
28
O. Okay