This is a preprint. Please check (and cite ) the accepted version at: Polymer Volume 173, 31 May 2019, Pages 20-26 DOI: 10.1016/j.polymer.2019.04.016 https://doi.org/10.1016/j.polymer.2019.04.016 The SI is attached at the end of this file. SI videos are available at: https://hagayshpaisman.wixsite.com/shpaismanlab/copy-of-videos Simultaneous Polymerization and Patterning: A One Step Acoustic Directed Assembly Method Silvia Piperno, Haim Sazan and Hagay Shpaisman* Department of Chemistry, Institute for Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 5290002, Israel ABSTRACT: Processing materials to form microstructures in the least possible number of steps is desired in order to reduce cost and processing time. In this work, we propose a new approach where standing surface acoustic waves are used to order materials prepared in- situ rather than preformed materials, providing a new method for one-step (simultaneous polymerization and patterning) directed assembly. We demonstrate this concept on products of an ongoing chemical reaction such as polymerization of polydimethylsiloxane (PDMS). We have found that by directed coalescence of nano-sized intermediate nucleation sites, continuous polymeric microstructures