We demonstrate a macromer-type bisepoxide, poly(ethylene
glycol)
diglycidyl ether, polymerizing readily with a trifunctional polyetheramine
Jeffamine T-403 in water to facilitate the development of a series
of microgels abbreviated as PMG. Simply by varying the concentration
of the as-prepared thermoresponsive intermediate prepolymer from 1
to 2 and 4%, hydrodynamic sizes of the resulting P1MG, P2MG, and P4MG
are easily tuned in the submicrometer to micrometer range shown by
the dynamic light scattering results. Besides size difference, these
microgels also deform differently, where the drying-induced deformation
effect is most severe for P1MG and least prominent for P4MG. Simple
evaporative deposition of PMG into multilayer packing provides versatile
and green options for microgel-mediated surface structuring of agarose
hydrogels. Specifically, deformabile P1MG- and P2MG-derived coatings
render agarose gel microwrinkle textures by buckling against swelling-induced
surface instability. Conversely, stiffer P4MG microgels lead to a
patchy patterned hierarchical coating on agarose, similar to the cracking
effect in drying colloidal films. The straightforward microgel-on-macrogel
strategy allows integration of both wrinkle and patchy patterns to
generate Janus-type agarose gels, just by rationally arranging the
coating sequence. Diversifying topographic features attainable through
microgel-based coatings on hydrogels could potentially make the sustainable
and biocompatible material of agarose a more compelling choice for
bioapplications. Brief demonstrations of the broad applicability of
P1MG toward wrinkling of proteinaceous and synthetic hydrogels further
highlight promising prospects of the PMG microgel-on-macrogel functionalization
strategy.