UV‐Induced Disulfide Formation and Reduction for Dynamic Photopatterning

Abstract

Here we present the UV-induced disulfide formation (UV-DF) and disulfide reduction (UV-DRSpatially resolved functionalization of surfaces is important in a variety of research fields ranging from microfluidics [1] and electronics [2] to biotechnology. [3] In this context, photochemical reactions attracted attention, because they offer both spatial and temporal control of surface modification. [4] To date, a variety of light-triggered reactions, for example, thiol-ene [5] /yne, [6] photoinitiated azide-yne, [7] tetrazole-ene, [8] tetrazole-thiol, [9] and phototriggered Diels-Alder reactions, [10] have been exploited for surface functionalization. However, the majority of the existing methods are restricted to irreversible surface functionalization because of the formation of relatively non-reactive covalent bonds. In contrast, reversible photochemical modifications provide more diverse possibilities for surface manipulation. These can be applied for example, for dynamic tuning of interfacial properties, stimuli-responsive activation and deactivation of specific functions, or reversible attachment/detachment of functional moieties.To the best of our knowledge, only three examples of reversible phototriggered surface functionalization methods based on thiol−quinone methide reaction, [11] addition fragmentation chain transfer reaction of allyl sulfides with thiols, [12] and photodynamic disulfide exchange reaction (PDDE), [13] have been reported. Here we demonstrate two photo-induced reactions allowing for the spatially and temporally controlled thiol-disulfide interconversions, namely UVinduced disulfide formation (UV-DF) and disulfide reduction (UV-DR) reactions. These reactions are used to demonstrate reversible UV-induced surface modification, patterning, attachment as well as detachment of functional molecules (Scheme 1).Thiol-disulfide interconversion is well-documented to proceed via the thiolate-centered mechanism; [14] however, it lacks the spatial control required for surface patterning. Recently,

Design of Active Interfaces Using Responsive Molecular Components

“…Alternatively, photodynamic patterning also allows for spatiotemporal control of wettability at surfaces, as demonstrated previously for disulfide formation/reduction strategies ( Figure A) . The modularity of the disulfide bond provides the opportunity to attach, exchange and detach different thiol components at a thiol‐modified surface without a significant loss of functionality over time.…”

3D Laser Micro‐ and Nanoprinting: Challenges for Chemistry

“…It was mentioned above that care should be taken during the photo(co)polymerization of disulfides containing cross‐linkers. Indeed, disulfides are sensitive to UV light and can undergo exchange reactions with other disulfide molecules, irrespective of the solvent conditions, which implies that light can be employed to degrade networks in the presence of soluble thiols and disulfides.…”

(De)bonding on Demand with Optically Switchable Adhesives

“…Numerous materials based on disulfide bond exchange can be found in the literature, and the relatively weak dynamic bond has been widely used for the design of healable or recyclable materials . A particularly attractive feature of the disulfide bond is its sensitivity to various stimuli such as heat, pH, or light, and a few examples of disulfide containing thermoresponsive adhesives have been reported . A photohealable semicrystalline shape‐memory polydisulfide network was investigated by Rowan and co‐workers, who demonstrated that such materials may also serve as reversible, on‐demand debondable adhesives ( Figure a) .…”