Macroscopic
supramolecular assembly (MSA) of building blocks larger
than 1 μm provides new methodology for fabrication of functional
supramolecular materials and a platform for mechanism investigation
of interfacial phenomena. Most reports on MSA are restricted to soft
hydrogels, and supramolecular groups can be directly integrated into
a hydrogel matrix to generate sufficient attraction for maintaining
macroscopic assemblies. For non-hydrogel stiff building blocks, two
layer-by-layer modification processes consisting of flexible spacing
coating and additional interacting groups are necessary to enable
MSA, which is laborious and time-consuming. Approaches for highly
efficient MSA based on flexible spacing coating are desired. In this
work, MSA of polydimethylsiloxane (PDMS) building blocks is demonstrated
by inducing microgel films that serve as both flexible spacing coating
and surface functional groups, thus avoiding a two-step LbL modification
process. By the varying bilayer number of microgel films, the MSA
probability of modified PDMS increases from 54% at 3 bilayers to 100%
at 6 bilayers. Control experiments and in situ force measurement strongly
support the obtained MSA results and verify the dominant role of the
microgel film as a flexible spacing coating and a supramolecularly
interactive layer in achieving MSA. Moreover, the underlying mechanism
is interpreted as low Young’s modulus microgel films rendering
surface groups highly mobile to enhance the multivalent interfacial
binding. Taken together, this work has demonstrated the feasibility
of MSA of rigid building blocks assisted by microgel films as flexible
spacing coating and supramolecularly interactive layer simultaneously,
which may extend the application fields of microgel materials to interfacial
adhesion and advanced manufacturing with MSA methodology.