Surface Engineering with Polymer Brush Photolithography

Abstract

Surface‐tethered macromolecules, or polymer brushes, offer a unique platform for coating surfaces for a wide variety of applications. Surface‐initiated polymerization (SI‐P), through which polymer brushes can be grown directly from an initiator‐functionalized surface, offers a facile, highly customizable approach that is synergistic with photolithography. Using a variety of photolithography devices and SI‐Ps, complex polymer brush architectures can be fabricated with great spatial and temporal control. This article not only addresses techniques, advancements, applications, and possible future directions within the field of polymer brush photolithography, but it also provides resources to assist the reader in selecting the polymerization technique and photolithography device most conducive to a given endeavor.

Rapid High‐Resolution 3D Printing and Surface Functionalization via Type I Photoinitiated RAFT Polymerization

“…To further demonstrate the utility of the RAFT mediated 3D printing system to allow complex surface functionalization, time‐dependent surface functionalization of 3D printed objects was performed. As demonstrated previously in surface initiated photoinduced RDRP, polymer brush growth can be tailored by regulating the light dose [38b, 39d, 40, 41] . For instance, Hawker and co‐workers showed that gradient grayscale masks could be used to tailor the optical density at the surface of ATRP‐initiator functionalized silicon substrates, thus providing spatially controlled brush growth through a photo‐ATRP process [39d, 42] .…”

“…As EHA is a hydrophobic monomer, it was posited that functionalizing the 3D printed object surface with PEHA brushes would change the surface wettability of the material compared to the base P(DMA‐ co ‐PEGDA) polymer. Notably, the 3D printed base object was not removed from the build stage after printing, which allowed the subsequent digitally masked photolithography to be performed using the 3D printer without tedious realignment of the substrate [38b, 39d, 40] . A spatially controlled photopolymerization using the digital light projector of the 3D printer was then performed on one half of the 3D printed base object for 3 min.…”

Mixed Polymer Brushes for “Smart” Surfaces

“…Polymer brush films therefore provide the potential to not only improve household goods but also address larger-scale issues such as anti-fouling and drug delivery [22,23]. Potential applications span a wide range [2,[24][25][26][27][28][29] from organic light emitting diodes (OLEDs) [30] to membranes for desalination and gas separation [31], to protein adsorption [32]. Additional applications include those that require controlled surface wettability [33] and heterogeneous catalysis [34].…”

Preparation of Patterned and Multilayer Thin Films for Organic Electronics via Oxygen‐Tolerant SI‐PET‐RAFT

“…The resulting, distinct pattern of projected light catalyzes polymer brush growth only on the parts of the surface that are illuminated. In this way, the pattern of polymer brush growth can be customized without the necessity of fabricating customized photomasks, enabling rapid, cost effective, and complex patterning [15, 65, 66] …”