We report on a new, extremely fast, very simple and versatile method to produce polymer brushes by surface-initiated controlled/living radical polymerization.
A method is presented that allows for the first time the preparation of highly defined polymer brush coatings on the wafer-scale under ambient conditions (room temperature, exposure to air) from a broad variety of monomers. The discovered high oxygen-tolerance of the surface-initiated Cu(0)-mediated controlled radical polymerization (SI-CuCRP) yields entire wafers homogeneously covered by a polymer brush of linear, high molar mass polymers with narrow dispersities (Đ = 1.1) at extremely high grafting densities (≈1 chain per nm 2 ). The low-tech and air tolerant method requires only ≲4 mL reaction solution containing a monomer and a ligand between two facing substrates. Thus, the SI-CuCRP is scalable to any surface area with minimal costs and minimal equipment. Despite the simplicity of the method, the high endgroup fidelity of SI-CuCRP is demonstrated by the preparation of a tetrablock copolymer brush which is the first example of a higher order block copolymer brush prepared by any surface-initiated polymerization. Finally, we present a new facile lithographic technique, the copper plate proximity printing (CP 3 ), which relies on the proximity of the bulk copper surface to the initiator-bearing substrate. The CP 3 is resist-and development-free and transfers the copper plate profile (of a copper coin) directly into an image composed of a 3D polymer brush. † Electronic supplementary information (ESI) available. See
Surface-initiated Cu(0)-mediated controlled radical polymerization (Si-CuCRP) can be successfully applied to fabricate poly[(oligoethylene glycol)methyl ether methacrylate] (POEGMA) brushes in one pot, presenting a grafting-density gradient across the surface. This is achieved by continuously varying the distance (d) between a copper plate, used as a source of Cu species, and the initiator-functionalized substrate. X-ray photoelectron spectroscopy (XPS) analysis of monolayers of Cu Iselective ligands demonstrates that a higher concentration of activator species diffuses to the initiating substrate in areas closer to the copper plate, a progressive decrease in activator concentration being observed upon increasing the distance between the two surfaces. As confirmed by the SI-CuCRP kinetics measured at different positions along the gradient, radical-termination reactions between propagating chains limit the grafting density of POEGMA grafts where the diffusion of activators is favored (i.e., at d → 0). This effect decreases with increasing d, ultimately yielding a gradual variation of POEGMA grafting density across the substrate. We have investigated the influence of grafting-density variation across the gradient on the swelling of POEGMA brushes as well as on their nanomechanical and nanotribological properties, measured by a combination of variable angle spectroscopic ellipsometry (VASE), colloidal-probe atomic force microscopy (CP-AFM), and lateral force microscopy (LFM). The results of these tests highlight how loosely grafted POEGMA chains incorporating a substantial amount of water can be significantly deformed by a shearing AFM probe, exhibit relatively high friction, and generate friction-vs-load (F f −L) profiles that follow a sublinear trend described by a Johnson− Kendall−Roberts (JKR) modeltypical of deformable films of high surface energy. In contrast, more densely packed POEGMA brushes incorporate less solvent and display very low friction, with F f −L data following a linear progression according to Amontons' law.
We present the "on water" surface-initiated Cumediated controlled radical polymerization ("on water" SI-CuCRP) that converts hydrophobic monomers in aqueous reaction medium to polymer brushes at unparalleled speed and efficiency.The method allows the facile conversion of avariety of common monomers under most simple reaction conditions and with minimal monomer amounts to thicka nd homogeneous polymer brushes.The highly living character of the "on water" SI-CuCRP allowed the preparation of decablock (homo)polymer brushes and opens the pathway to sequentially controlled polymer brushes on solids.
Dynamic color-changing nanomaterials have been widely investigated for applications in fields like optical sensors, wearable activity monitors, smart electronic devices, and anticounterfeiting materials due to the excellent ability to change their optical properties with external variation. Here, a simple metal–insulator–metal (MIM) trilayer Fabry–Perot resonance cavity with a poly(N-isopropylacrylamide) (PNIPAm) brush layer as a responsive element is reported as a thermal-induced colorimetric response platform. The dynamic changes of conformation and physical properties of PNIPAm brush layer in response to external signals give rise to a significant color change of the MIM Fabry–Perot resonance cavity. This MIM Fabry–Perot resonance cavity shows the advantages of dynamic color change, rapid response, good repeatability, and simple construction. Additionally, the as-prepared MIM cavity shows great potential in various applications such as color printing, multicolor indicator, and information anticounterfeiting.
A facile and universal oxygen-tolerant, capillary microfluidic-derived, controlled radical polymerization for surface structuring (gradient and patterned polymer brushes) is reported. A syringe pump and a filter paper sheet are used as capillary microfluidic to supply the reaction solution (monomer, solvent, and ligand) to a sandwichshaped setup by placing a flat copper plate onto an ATRP initiator-modified substrate and resulting in gradient polymer brush formation with controlled thickness, steepness, and grafting area, polymers are showing the high chain-end fidelity. Two different polymer brushes (binary polymer brushes) can be simultaneously grown from both ends of the initiator modified substrate by using this method, which can be used to study the interfacial properties of different polymer brushes.
The detection of thiocyanate (SCN − ) is particularly important in industrial effluents and biological fluids because of the toxic nature of SCN − . Herein, a metal−insulator−metal (MIM) resonator for visual detection of SCN − is presented based on a poly[(2-(methacryloyloxy)ethyl) trimethylammonium chloride] (PMETAC) brush. The MIM resonator exhibits obvious color change as the concentration of SCN − changes, which can be easily distinguished by the naked eyes. In addition, the as-prepared MIM resonator also shows the advantages of good anti-interference, excellent reusability, and fast response rate. Combining the above advantages, the proposed MIM resonator may provide a broad perspective for a wide variety of visible-light applications.
Poly(2‐oxazoline)s (POx) bottle‐brush brushes have excellent biocompatible and lubricious properties, which are promising for the functionalization of surfaces for biomedical devices. Herein, a facile synthesis of POx is reported which is based bottle‐brush brushes (BBBs) on solid substrates. Initially, backbone brushes of poly(2‐isopropenyl‐2‐oxazoline) (PIPOx) were fabricated via surface initiated Cu0 plate‐mediated controlled radical polymerization (SI‐Cu0CRP). Poly(2‐methyl‐2‐oxazoline) (PMeOx) side chains were subsequently grafted from the PIPOx backbone via living cationic ring opening polymerization (LCROP), which result in ≈100 % increase in brush thickness (from 58 to 110 nm). The resultant BBBs shows tunable thickness up to 300 nm and high grafting density (σ) with 0.42 chains nm−2. The synthetic procedure of POx BBBs can be further simplified by using SI‐Cu0CRP with POx molecular brush as macromonomer (Mn=536 g mol−1, PDI=1.10), which results in BBBs surface up to 60 nm with well‐defined molecular structure. Both procedures are significantly superior to the state‐of‐art approaches for the synthesis of POx BBBs, which are promising to design bio‐functional surfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.