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Sketch of polymer brush-based adhesion via (A) the entanglement and physical interactions and (B) the covalent bonds between the polymer brushes and a bulk polymer matrix.
Source publication
Creating strong joints between dissimilar materials for high-performance hybrid products places high demands on modern adhesives. Traditionally, adhesion relies on the compatibility between surfaces, often requiring the use of primers and thick bonding layers to achieve stable joints. The coatings of polymer brushes enable the compatibilization of...
Contexts in source publication
Context 1
... commercial adhesives, e.g., epoxy, polyurethane, and acrylic adhesives utilize both chemical and physical bonds, the ability of polymer brushes to interpenetrate into bulk polymer matrices enables a unique mode of interaction in terms of chain entanglement. Entanglement constitutes an important interaction in the category of non-covalent bonds, resulting in a nanoscale mechanical interlocking ( Figure 1A). While entropy generally drives mixing, the enthalpy of mixing is of key importance when considering polymers. ...
Context 2
... a polymer brush compatible with the adherend cannot be directly synthesized, polymer interpenetration and entanglement is unachievable. In that case, polymer brushes with reactive handles (functional groups) may be exploited to form covalent bonds between the brush and the adherend, thus facilitating adhesion through covalent bond formation ( Figure 1B). This approach often utilizes the curing of the adherend, e.g., in thermosets or rubbers, to facilitate bond formation to the polymer brushes and thus obtain adhesion. ...
Citations
... In addition to comprehensive works on the methods of fabrication of PB and their biomedical applications, [6][7][8] there are also specialized works reviewing the state-of-the-art in PB for tissue engineering, 9 photolithography of PB, 10 atomic force microscopy (AFM) characterization and molecular engineering of PB, 11 theory of PB in air, 12 and role of PB in interfacial adhesion and friction in laboratory scale, 13 and even in the large-scale applications. 14 In this work, we focus on very recent examples of applications of PB with various topologies, especially in demanding areas of medicine, 15 fabrication of optoelectronic devices, 16 and low-friction surfaces. 17 We focus on specific properties of PB grafted from the solid surfaces related to their unique macromolecular ordering and architecture, dynamic changes of macromolecular conformations, anisotropy of selected properties, nanomechanics, and so forth. ...
Surface‐grafted polymer brushes (PBs) are a versatile class of thin coatings that exhibit unique properties due to their densely grafted polymer chains. PBs are typically formed through surface‐initiated polymerizations, particularly reversible deactivation radical polymerizations, and macromolecules adopt extended conformations that differentiate them from classical polymer films. This review explores various applications of PBs, emphasizing their macromolecular ordering, dynamic conformational changes, anisotropic properties, and so forth. The growing interest in utilizing PBs for functional coatings is discussed in various fields, including electronic, biological, and environmental applications. In electronic applications, PBs find relevance in photovoltaics, energy storage devices, organic light‐emitting diodes, and organic electronics, showcasing their potential in advancing electronic technologies. In biological applications, they contribute to the formation of antifouling and antibacterial coatings, as well as superior lubrication and cellular adhesion, making them valuable in biomedical settings. Other applications include biosensors, bioimaging systems, and drug delivery systems, highlighting their significant contributions to medical advancements. Additionally, PBs play an important role in environmental applications such as water and wastewater treatment. A variety of recent examples of the applications of surface‐grafted PBs are presented, providing insights into their unique properties and architectures that contribute to their success in demanding areas of science and technology.
... Polymer layers can be added to surfaces to limit protein adsorption, often referred to as polymer brushes because of their adhesion to the surface at one end of the chain (Buhl et al., 2020). Polymers based on the ethylene glycol unit, such as polyethylene glycol (PEG) and Poly (ethylene oxide) (PEO) (Leckband et al., 1999), are commonly bonded to surfaces as coatings to prevent nonspecific protein fouling (Israelachvili, 1997;Wei et al., 2014;Fischer et al., 2018). ...
Biological applications of microfluidics technology is beginning to expand beyond the original focus of diagnostics, analytics and organ-on-chip devices. There is a growing interest in the development of microfluidic devices for therapeutic treatments, such as extra-corporeal haemodialysis and oxygenation. However, the great potential in this area comes with great challenges. Haemocompatibility of materials has long been a concern for blood-contacting medical devices, and microfluidic devices are no exception. The small channel size, high surface area to volume ratio and dynamic conditions integral to microchannels contribute to the blood-material interactions. This review will begin by describing features of microfluidic technology with a focus on blood-contacting applications. Material haemocompatibility will be discussed in the context of interactions with blood components, from the initial absorption of plasma proteins to the activation of cells and factors, and the contribution of these interactions to the coagulation cascade and thrombogenesis. Reference will be made to the testing requirements for medical devices in contact with blood, set out by International Standards in ISO 10993-4. Finally, we will review the techniques for improving microfluidic channel haemocompatibility through material surface modifications—including bioactive and biopassive coatings—and future directions.
... Yet another type of anti-adhesion coating is the use of a polymer brush which involves the use of polyethylene oxide (PEO) and the generation of a repulsive osmotic pressure to ward off bacteria. However, this approach has been unsuccessful in vivo because of its weak adhesion to moist medical devices, where microbial flagella and pili increase movement and adhesion, and is more successful in vitro [17,207]. Although most opportunistic microbes that produce biofilms can infect people, some of them can shield people from more dangerous infections [208]. ...
Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.
... Polymeric brush coating was chosen as the effective method for a multilayered coating system with multiple functionalities covering the nook and corners of the substrate with less active release rate of the biocide, low risk of chemical leaching [22]. It takes about 2-3 h for surface drying. ...
Marine structures are prone to biocorrosion, so developing a suitable coating system to combat corrosion is essential. The present work is focused on the development of a multilayered epoxy-based nanocomposite (NC) coating system reinforced with ZnO filler in the first layer coat (NC1), ZnO and Cu2O in the second layer (NC2), and the third layer consisting of a varying percentage of TiO2 with 5 wt%, 10 wt%, and 15 wt% of TiO2 designated as NC3, NC4, and NC5, respectively, as top coat on the bare steel. Brush coating was employed to fabricate the coatings. Surface morphology and mechanical properties, wettability, corrosion, and biocorrosion behavior of the bare steel and coated substrates were examined. Mechanical properties such as linear scratch hardness and posi adhesion test values of the coatings were found to be in the order NC1 < NC2 < NC3 < NC4 < NC5. The NC3-coating system comprising three layers of coating reinforced with 5 wt% TiO2 imparting hydrophobicity offered maximum resistance to microbial adhesion with 93% and 91% reduction in corrosion rate than the bare metal in natural and artificial seawater, respectively, after the 7th day of immersion. The bacterial and fungal cell counts in the biofilm after the 7th day of immersion were reduced by four and three orders of magnitude, respectively, in the nanocomposite against the bare substrate providing good biofouling resistance. NC3 coating also prevented the release of metal ions into the seawater and acted as a barrier for the leaching of metals from the coating underneath, thus, proving to be safe for the marine environment.
... Polymer brushes are a versatile class of coatings where one end of the polymer chains is grafted to a surface, with end-grafted polymer chains having numerous applications in colloid dispersion, anti-fouling surfaces, lubrication, adhesion, and sensing [1][2][3][4]. Experimental studies have investigated the behavior of neutral and electrostatically charged chain groups interacting with polar and nonpolar solvents and gases [5][6][7][8][9][10][11][12][13][14]. Computational simulations using molecular dynamics and Monte Carlo methods have explored the near-equilibrium molecular conformations of brushes in various chemical environments [11,[15][16][17][18][19][20][21]. ...
The steepest-entropy-ascent quantum thermodynamic (SEAQT) framework is utilized to study the effects of temperature on polymer brushes. The brushes are represented by a discrete energy spectrum and energy degeneracies obtained through the Replica-Exchange Wang-Landau algorithm. The SEAQT equation of motion is applied to the energy landscape to establish a unique kinetic path from an initial thermodynamic state to a stable equilibrium state. The kinetic path describes the brush's evolution in state space as it interacts with a thermal reservoir. The predicted occupation probabilities along the kinetic path are used to determine expected thermodynamic and structural properties. The brush density of a polystyrene brush in cyclohexane solvent is predicted using the equation of motion and demonstrates qualitative agreement with experimental density profiles. The Flory-Huggins parameter chosen to describe brush-solvent interactions affects the solvent distribution in the brush but has minimal impact on the brush density. Three types of non-equilibrium kinetic paths are considered, i.e., a heating path, a cooling path, and a heating-cooling path, differing in their entropy production, with properties such as tortuosity, radius of gyration, brush density, solvent density, and brush chain conformations calculated for each path.
... To be more specific, as presented in Fig. 7C, changing the grafted chains conformation to true brush would lead to a 90% increase in the work of adhesion, which may be associated with the enhanced interpenetration and entanglement of the polymer chains at the interface zone. As seen in Fig. 7A, in this case, the matrix and GR surface are in direct contact with each other providing the improved mechanical interlocking [75,76]. On the contrary, in the mushroom regime, the polymer molecules form a barrier layer at the interfacial region disrupting the aforementioned GR/matrix direct contact. ...
Tethered polymer chains are known to have a great potential in tailoring interfaces and promoting interfacial adhesion in polymer-based nanocomposites. In this context, this paper is aimed to explore the adhesion characteristics of poly(L-lactic acid)/graphene (GR) samples having a modified interface, where the PLLA chains at different grafting densities are attached on the GR surface. This is achieved through conducting pull-off tests employing all-atom molecular dynamics simulations. Monitoring the evolution of interfacial energy and pull-off force combined with the microstructural studies indicates that there exists an optimum coverage ratio (i.e., 0.002), beyond which the interfacial interactions would be disrupted. This is supported by the trend observed for variations of the adhesion characteristic such as interfacial normal strength and work of adhesion with the grafting density. To deeply analyze this issue, we further proceed to design composite systems of different architectures referred to as mushroom and brush-like conformations. It is demonstrated that the most effective molecular morphology is the one providing the highest degree of polymer chains entanglement. Also, failed attempts to reinforce adhesion by increasing the grafting density suggest that to have a beneficial chain arrangement, one should control several factors such as diffusion conditions, manufacturing methods, and grafting techniques.
... According to previous research, the first principles of quantum mechanics (QM) and molecular dynamics (MD) have become advantageous tools for studying the interaction mechanism between metals and non-metals [21][22][23][24]. MD can simulate the interaction law between atoms in a defined complex system on the atomic scale [25][26][27][28]. QM can study the motion law of microscopic particles in the material world. ...
As food and beverages require more and more green and safe packaging products, the emergence of polymer coated steel (PCS) has been promoted. PCS is a layered composite strip made of metal and polymer. To probe the bonding mechanism of PCS micro-interface, the substrate tin-free steel (TFS) was physically characterized by SEM and XPS, and cladding polyethylene terephthalate (PET) was simulated by first-principles methods of quantum mechanics (QM). We used COMPASS force field for molecular dynamics (MD) simulation. XPS pointed out that the element composition of TFS surface coating is Cr(OH)3, Cr2O3 and CrO3. The calculation results of MD and QM indicate that the chromium oxide and PET molecules compound in the form of acid-base interaction. The binding energies of Cr2O3 (110), (200), and (211) with PET molecules are −13.07 eV, −2.74 eV, and −2.37 eV, respectively. We established a Cr2O3 (200) model with different hydroxyl concentrations. It is proposed that the oxygen atom in C=O in the PET molecule combines with –OH on the surface of TFS to form a hydrogen bond. The binding energy of the PCS interface increases with the increase of the surface hydroxyl concentration of the TFS. It provides theoretical guidance and reference significance for the research on the bonding mechanism of PCS.
... The most commonly used, spraying or padding, significantly change the structure and properties of the surface layer of fabrics, used for conventional and high-tech applications in life. In order to achieve high adhesion in the polymer composition deposited on the fabric surface, the gas-dynamic method is increasingly used [16][17][18]; this way provides, in increasing forms of stability, parts of garments made of fabric or leather by application of the direct method of stabilization of surfaces by polymer compositions, in particular polymer composition based on waste of polyethylene terephthalate (PET) [19]. Various ways are usually used to combine the gas and liquid phase transfer and functionality of equipment into coated textiles. ...
... As we consider the polymer to be an elastic body, the amount of energy of its fixation is determined from [16]. If the tangential strain stresses are characterized by the allowable value of adhesive strength under critical deformation conditions, we obtain the following: ...
... Using (13), (14), (16), and (18) in (19), the value of the fixing force can be determined: ...
The polymer film, formed on fabric, has a diverse resistance to impact (shear) forces during deformation. An original model of the capillary-porous structure of the fabric, partially filled with polymer, was presented and discussed in this paper. Polymer material fixing relations were developed, taking into account the fabric structure and changes of polymer temperature. Experimental studies were performed on three different materials: artificial leather SK-2, GOST 16119-70 (230 g/m2); genuine beef skin, GOST 939-75 (2.2 g/m3); and fabric denim, GOST 29298-2005 (225 g/m2). The value of mathematical model analysis deviation compared with the experimental value was approximately 12%. The obtained mathematical dependences were the basis for predicting the increase of the dimensional stability of garments by applying hot melt polymer to its surface. It is also possible to design new equipment for its implementation.
... P olymer brushes become more popular due to their potential applications in multiple fields, such as surface modifications [1][2][3][4], biomedical engineering [5][6][7][8], etc. They are densely grafted polymer chains with one end attached to the surface or interface of silicon wafers, glass, gold particles or polymer substrates [9][10][11]. ...
The surface modifications are necessary to alter the inherent surface physical/chemical properties of materials in terms of adhesion, wettability, friction, biocompatibility etc. for using in textile, electronic and biomedical industries. Surface modifications are usually made by grafting of polymer brushes to the solid substrates. The grafting process allows controlling and manipulation of surface properties without changing the chemical structure of polymers. Besides their chemical structures, grafting density of polymer brushes and average distance between the polymer chains attached to the surface are also important parameters, affecting the intended use of the grafted materials. Synthesis of functional polymer brushes is generally carried out by one of surface-initiated controlled/living free radical polymerization techniques, namely Atom Transfer Radical Polymerization (ATRP), Nitroxide-Mediated Polymerization (NMP), Photoiniferter-Mediated Polymerization (PIMP) and Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT). This review reports the strategies of these techniques for generating polymer brushes and summarizes the application of polymer brushes in multiple fields.
