Assembly Mechanism of MSA
Normally, macroscopic building blocks made by micro-fabrication have a surface roughness much larger than molecular interactive distance of supramolecular interactions. Therefore, when macroscopic building blocks directly modified with supramolecular groups and collide with each other, it is probable that only very limited supramolecular groups could reach the interactive distance. As a result, the interfacial strength is not sufficient to realize MSA. To address this problem, we try to interpret the assembly mechanism of MSA with the following hypothesis: the point to realize MSA is to ensure that assembled supramolecular groups at the interface could lead more groups to reach interactive distance and make multivalency occur. With the reality of rough surface and possible inhomogeneous group distribution, interface deformation should be essential to realize multivalency. For this reason, we consider the elastic modulus of building blocks as metrical parameter to study the dependence of interface deformability on assembly behaviors. Meanwhile, we have checked other influential factors such as surface chemistry, assembly kinetics etc. Taken together, we found the dominant role of good interface deformation (reflected by low elastic modulus) in achieving MSA.