Controlling the Aspect Ratio of Supramolecular Fibers by Ultrasonication

Tailoring the fiber length of supramolecular fibers with a homogeneous length distribution is challenging. Typically, self-assembly processes, a bottom-up approach, allow controlling the supramolecular fiber diameter but not the fiber length. Therefore, in this study, a top-down approach, namely ultrasonication, is applied to achieve dimensional control of the length of supramolecular fibers. As a supramolecular building block, the benzenetrisamide (BTA),1,3,5-tris(2,2-dimethylpropionylamino)benzene (t-Bu-BTA), is selected since it effectively forms rigid supramolecular submicron fibers from solution. The important ultrasonication processing parameters, such as sonication time, fiber concentration, dispersion medium, and dispersion temperature are systematically varied to determine their influence on the final fiber length and length distribution. Controlling the cutting into short submicron fibers is readily achieved by adjusting the applied sonication time and the viscosity of the dispersion medium. Based on these results, it is now possible to tailor the aspect ratio of supramolecular submicron fibers.