(Sub-)microscale patterning via microcontact printing (μCP): recent advances, applications and future perspectives.

Microcontact printing (μCP) is a versatile and low-cost technique for surface patterning, allowing for the fabrication of intricate designs with relative ease. However, despite these clear advantages, the application of μCP has predominantly focused on smooth, uniform surfaces, while rough, capillary-active, or hydrogel surfaces have largely been neglected in existing literature. This article aims to review the latest advances in μCP, tracing the evolution of patterning techniques and highlighting recent applications across various fields. Our discussion will encompass both fundamental developments in technology and practical implementations that illustrate its potential. In the last section, we will address the question why non-smooth surfaces have gathered less interest and aim to propose strategies for overcoming the inherent challenges they pose. With this contribution, we will also provide a perspective by shifting our focus to the specific challenges posed by capillary-active surfaces. We will introduce the innovative concept of polymer brush-supported μCP (PolyBrushMiC), which could serve as a promising strategy to address these challenges. By incorporating polymer brushes, we can enhance the compatibility of μCP with rough surfaces, enabling more effective pattern transfer and improved stability of printed features.