High‐Resolution Patterned Functionalization of Slippery “Liquid‐Like” Brush Surfaces via Microdroplet‐Confined Growth of Multifunctional Polydopamine Arrays

Abstract

Slippery omniphobic covalently attached liquids enable smooth, transparent, pressure‐ and temperature‐resistant, and liquid‐repellent coatings. Patterned functionalization of such surfaces would drive technology developments and fundamental understandings in broad applications from biosensors to sustainable smart surfaces. Herein an additive microcontact printing approach in combination with the microdroplet‐confined synthesis is developed to functionalize slippery surfaces tethered with “liquid‐like” linear poly(dimethylsiloxane) by multifunctional polydopamine (PDA) arrays. Using glycerol and non‐ionic surfactant Tween‐20, microdroplet arrays containing dopamine monomers are printed onto the slippery surfaces and serve as microreactors for the in situ growth of PDA micropatterns. The confined growth approach enables tunable feature size, height, and morphology of the patterns, through which sub‐micrometer PDA dot arrays over centimeter‐square patterning area can be reliably achieved. Furthermore, the reactive and hydrophilic PDA micropatches allow further functionalization of the slippery surfaces with a diverse variety of materials, meanwhile the anti‐fouling and dynamically dewetting “liquid‐like” brushes permit minimum background contamination. Proof‐of‐concept demonstrations include PDA‐initiated photografting for stimuli‐responsive polymer functionalization, protein immobilization for microarray‐based immunoassays, as well as sliding‐induced selective dewetting of organic solutions to pattern photoluminescent perovskite microcrystals and nanoparticles. The current approach illustrates the potential for applying patterned slippery surfaces with multifunctional architectures in many fields.

Reversibly Stretchable Organohydrogel-Based Soft Electronics with Robust and Redox-Active Interfaces Enabled by Polyphenol-Incorporated Double Networks

“…In addition, TA-gel-supported microsensors integrated with stretchable supercapacitors were demonstrated for multifunctional on-skin applications. Not limited to supercapacitor and strain/UV sensing presented in this work, various polyphenol-incorporated gels based on diverse polymer networks could be further developed to accommodate wearable microbatteries, healable and recyclable electronics, , or self-powered chem/biosensing. , Furthermore, since TA is also a bioactive compound displaying antibacterial and antioxidation properties, our approach could pave a route to soft ionic conductors with integrated physical/chemical/biological functions and spatiotemporal control, , which is anticipated to drive advances in wearable monitoring, “green” ubiquitous electronics or clinical prospects in implanted devices and regenerative medicine.…”

Robust and durable liquid-repellent surfaces

“…143 Fang et al fabricated a highly smooth (roughness of <1 nm), ultrathin (thickness of ∼2 nm) and transparent slippery “liquid-like” coating on silicon wafer substrate through one-step condensation under heating (100 °C for 24 h). 274 The grafted PDMS chains possess high mobility through rotational and/or bending motions since only one end is covalently grafted to the surface, 275 and the mobile PDMS chains can facilitate the motion of triple-phase contact lines by minimizing the Gibbs free energy barriers between metastable states, which imparts the coated surfaces with excellent liquid repellence (Fig. 17c).…”

Patterning meets gels: Advances in engineering functional gels at micro/nanoscales for soft devices

“…30 The dewetted precursors can be also formed assisted by printing hydrophilic polydopamine (PDA) arrays on a hydrophobic surface, allowing a sub-10-μm resolution. 31 Another interesting work utilized a deformable elastic substrate for dewetting of microgels, in which the pattern shape can be tuned by applying tensile strains (Figure 2, left). 15 For patterning in a direct-write manner, the inks can be precisely delivered to the desired region without affecting the background.…”

“…Alternatively, dewettiing of ink precursors on patterned hydrophilic‐hydrophobic arrays also facilitates the formation of microarrays of gel building blocks 30 . The dewetted precursors can be also formed assisted by printing hydrophilic polydopamine (PDA) arrays on a hydrophobic surface, allowing a sub‐10‐μm resolution 31 . Another interesting work utilized a deformable elastic substrate for dewetting of microgels, in which the pattern shape can be tuned by applying tensile strains (Figure 2, left) 15 .…”