Surface Wrinkling: A Versatile Platform for Measuring Thin-Film Properties

Surface instabilities in soft matter have been the subject of increasingly innovative research aimed at better understanding the physics of their formation and their utility in patterning, organizing, and measuring materials properties on the micro and nanoscale. The focus of this Review is on a type of instability pattern known as surface wrinkling, covering the general concepts of this phenomenon and several recent applications involving the measurement of thin‐film properties. The ability of surface wrinkling to yield new insights into particularly challenging materials systems such as ultrathin films, polymer brushes, polyelectrolyte multilayer assemblies, ultrasoft materials, and nanoscale structured materials is highlighted. A perspective on the future directions of this maturing field, including the prospects for advanced thin‐film metrology methods, facile surface patterning, and the control of topology‐sensitive phenomena, such as wetting and adhesion, is also presented. Wrinkling instabilities have enabled new thin‐film measurement strategies and are energizing research efforts to pattern and control surfaces in unique and powerful ways. Recent work in the field is reviewed, focusing on how instability‐based techniques can meet future metrological challenges and provide low‐cost and straightforward approaches to active and on‐demand management of material properties.