Continuous Surface Polymerization via Fe(II)‐Mediated Redox Reaction for Thick Hydrogel Coatings on Versatile Substrates

Abstract

antiwear/lubrication, [2] antifouling, [3,4] drag-reduction, [5] and bioactivity of medical materials. [6,7] The development of facile and versatile strategies for surface chemical modification to all materials is of immense scientific interest. To date, a number of methods have been developed for the functional modification of material surfaces including surface selfassembly, [8][9][10] surface chemical grafting based on coupling reaction, [11][12][13] surfaceinitiated radical polymerization, [14][15][16][17][18][19][20] etc. However, they all have their limitations. In typical case, surface self-assembly needs that the grafted surfaces are chemically reactive. Surface chemical grafting is generally not a straightforward process, for which it needs to preferentially introduce reactive groups on the grafted surfaces. Surface-initiated polymerizations also require attaching initiator onto the target surface and then graft polymers, which are generally sophisticated (inert atmosphere, UV, or heating aid). Importantly, it is still challenging to develop universal approach to modify a wide range of materials. Russell and co-workers reported a generalized approach to modify materials by spinning copolymers onto solid surfaces, [21] including metal, metal oxide, semiconductor, and polymers. The modification process is complex and under harsh condition, which needs a spinning temperature of 250 °C and a post-crosslinked treatment. Thus, the development of versatile strategy for surface modification of a wide range of materials is essential for practical applications. Inspired by excellent attachment capability of natural mussel adhesive proteins, [22] scientists discovered polyphenolic chemistry for universal surface modification. [23][24][25][26] For instance, polydopamine coating technology has been applied to a wide range of materials with any size, shape, and structure, [27,28] including noble metals, metal oxides, ceramics, and synthetic polymers, showing many potential applications, [27] especially for wet adhesion. [29] The approach is limited to the modification with polyphenolic compounds. Hydrogel is one kind of wet materials with 3D crosslinking network that can be used in wet and biological environment. Both of its strength, [30,31] toughness/ elasticity, [32,33] and water content [34] can be well controlled. Due to their remarkable features including hydrophilicity, elasticity, The development of versatile generalized strategies for easy surface modification is of immense scientific interest. Herein, a novel mechanism to form functional hydrogel coatings on a wide variety of substrate materials including polymers, polymeric resins, ceramics, and intermetallic compounds, enabling easy change of the surface wettability and lubrication property, is reported. In situ polymerization and hydrogel coating formation is initiated by free radicals generated through the redox reaction between Fe 2+ and S 2 O 8 2− at the solid-liquid interface, which shows controllable growth kinetics. Hydrogel modification is fast, co...

Visible-light-assisted multimechanism design for one-step engineering tough hydrogels in seconds

“…(2) Ru(II)/S 2 O 8 2− is more efficient than Ru(II)/amines, Fe 2+ , and heating for initiating polymerization (Supplementary Fig. 10 ) 30 – 32 . (3) High-yield Ru(III)-triggered coupling of phenols is achieved in seconds 25 .…”

An Updated Review of Macro, Micro, and Nanostructured Hydrogels for Biomedical and Pharmaceutical Applications

“…Therefore, the modification of these devices with hydrogels for the production of functional materials have been widely exploited. For instance, grafted hydrogels may be used for the development of substrates with modified hydrophilicity and swelling characteristics [ 121 , 122 , 123 ], antimicrobial and antifouling surfaces [ 124 , 125 , 126 ], scaffolds for tissue engineering [ 127 , 128 ], smart materials [ 129 , 130 ], and localized drug delivery [ 131 ].…”

Recent Advances in Bioinspired Gel Surfaces with Superwettability and Special Adhesion

“…Thus, crosslinked polymer brushes were developed to address the above challenge (Figure 11a). [157] This method enabled good control over the chemical components, thickness, and network structures of the hydrogel layers, easily changing the surface wettability, and lubrication properties. [152] By comparison, the PAAm polymer brushes were also prepared.…”

“…By contrast, the shear force increased with an increasing shear rate for the cross‐linked brushes, an effect attributed to the suppression of interpenetration by cross‐linking. Recently, Ma et al developed a versatile method for the rapid fabrication of functional hydrogel coatings on the surfaces of various complex structures by catalytically initiated radical polymerization on surfaces, which occurred through the redox reaction between Fe 2+ and S 2 O 8 2− at the solid/liquid interface . This method enabled good control over the chemical components, thickness, and network structures of the hydrogel layers, easily changing the surface wettability, and lubrication properties.…”