Brushing up functional materials

Abstract

Surface-grafting polymer brushes (SPB), which are used in a versatile technique to easily realize surface modifications, can be commonly used to change the inherent surface physical/chemical properties of materials. In particular, producing functional polymer brushes with well-defined chemical configurations, densities, architectures, and thicknesses on a material surface has become increasingly important in many fields. Achieving such goals is highly dependent on the progress of novel surface-grafting strategies, which are commonly based on surface-initiated polymerization (SIP) methods. On the other hand, practical applications have been given more attention since the SPB technique enables the engineering of materials with diverse functions. This review reports some new grafting strategies for generating polymer brush layers and then systematically summarizes research advances in the application of polymer brush-modified materials in multiple fields. Correspondingly, some necessary challenges of the SPB technique are unreservedly pointed out, with consideration given to its real applications in the future. The aim of this article is to tell readers how to engineer functional materials through SPB techniques and what can be done with polymer brushes in the future.

Mixed Polymer Brushes for “Smart” Surfaces

“…In contrast, "grafting from" (i.e., surface-initiated polymerization) requires diffusion of only small monomers to an actively growing chain end on the surface. As a result, greater polymer grafting densities can be achieved via "grafting from" than via "grafting to" due to the improved mass transport and decreased steric hindrance [1,2,11,13,14,66,67].…”

“…The chemical connection between polymer and substrate improves durability and provides the potential for stimuli-responsive properties [3]. For detailed reviews on homopolymer brushes, the reader is referred to a series of previous articles [1,2,[4][5][6][7][8][9][10][11][12][13][14]. Using different anchoring chemistries, polymer brushes can coat various surfaces, including silicon [15], silica [16], gold [17], metal oxides [18], polymers [19], etc., and various surface geometries including planar substrates [20], nano particles [10] and free-standing films [21].…”

Surface Characterization of Electro-Assisted Titanium Implants: A Multi-Technique Approach

“…Furthermore, Bosh employed the EDP for the manufacturing of the Halar ® coating, providing a hard and tough layer to the implant, as well as outstanding additional properties for a bio-coating (i.e., abrasion resistance, biological stability, low surface energy, and coefficient of friction) [116]. Nanoindentation outcomes revealed values of hardness and elastic modulus (by taking the average of five data points) of 46.8 ± 0.4 MPa and 1.2 ± 0.7 GPa, respectively, slightly lower than the one reported for native bone (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Furthermore, other synthetic polymers, such as Polyetheretherketone (PEEK) can be easily electrophoretically deposited on a Ti alloy for improving bio-tribological application (e.g., wear resistance, corrosion resistance in Ringer's solution) as well as the mechanical properties, as reported by Sak et al [117].…”

“…In this respect, polymers provide cells with a plethora of chemical, topographical, and mechanical cues [7]. Indeed, the polymers' physico-chemical features (e.g., surface chemistry, wettability, roughness, topography, and stiffness) affect cell adhesion, morphology, and proliferation [8]. Furthermore, the three-dimensional architecture of polymeric materials, including porosity, impact cell motility, as well as cell metabolism and transport processes [9].…”

Interfacial nanoconnections and enhanced mechanistic studies of metallic coatings for molecular gluing on polymer surfaces

“…[23][24][25][26] Among these, surface-the use of graing polymer brushes, which are commonly based on surface-initiated polymerization methods, leads to an increase in the numbers of covalent bonds between circuits and substrates, which are stronger than electrostatic interactions, hydrogen bonds, and van der Waals forces. 27 This advantage, together with high efficiency and simplicity, makes molecular graing attractive for improving interfacial adhesion in exible electronics. For example, the Zheng group 12 prepared transparent and covalently bonded polymer coatings (namely PMETAC) on different substrates, enhancing the adhesion of printed multiscale, exible, foldable, and stretchable metal conductors signicantly.…”