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,

Functionalization of Poly(oxindole biphenylylene) membranes by photoinduced thiol-yne click chemistry

“…The modification with PEG-SH led to the formation of more hydrophilic surface, because of its characteristic polyether structure. The values obtained for the surfaces modified with multifunctional thiol compounds are similar to those previously reported in the literature for other thiol-based modifications 27 . Notably, PETMP modified surfaces exhibited relatively higher hydrophilicity due to the higher number of thiol functions.…”

Neat Linear Polysiloxane-Based Ionic Polymers: Insights into Structure-Based Property Modifications and Applications

“…Thus, there appears to be an optimal grafting density range that results in a phase transition. An unanswered question in this work involves the 365 nm wavelength used to photo-initiate the thiol-ene click chemistry This radiation can also induce the formation of disulfide linkages in primary alkyl thiols [49], and they may also contribute to the different physical states of the materials. [40].…”

Reconfiguring surface functions using visible-light-controlled metal-ligand coordination

“…Such surfaces can switch only between two functional states because photoswitchable compounds interconvert between two isomers under ultraviolet (UV)/visible-light irradiation. Reconfigurable surfaces, which can be converted into multiple states, have been constructed using photoreactions such as the photodynamic disulfide exchange reaction 18 , thiol–quinone methide reaction 32 , addition–fragmentation chain-transfer reaction 33 , and thiol–disulfide interconversion 19 . These photoreactions enable fabrication of customized surfaces on demand.…”