Surface Hydration and Antifouling Activity of Zwitterionic Polymers

Interrupting marine fouling with active buffered coatings

Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta.

Salt-Screened Transition toward Bulk-Like Water Dynamics near Polymeric Zwitterions

The superior antifouling performance of zwitterionic materials is commonly linked to their hydration structure, in which tight surface binding of water molecules inhibits solute adsorption. However, there is comparatively little direct experimental data on the hydration water structure and dynamics around zwitterionic moieties, including the longer-range behavior of the hydration shell that modulates the approach of solutes to the polymer surface. This work experimentally probes the dynamics of the diffusing hydration water molecules around a series of zwitterion chemistries using Overhauser dynamic nuclear polarization relaxometry. Surprisingly, water dynamics measured within ∼1 nm of the zwitterions were minimally inhibited compared to those near uncharged hydrophilic or cationic side chains. Specific dissolved ions further enhance the water diffusivity near the zwitterions, rendering the hydration shell bulk water-like. These results that the hydration of a zwitterion surface is nearly indistinguishable from bulk water suggest that these surfaces are "invisible" to biological constituents in a manner tunable by the ionic environment and the chemical design of the zwitterionic surface.

Injectable alginate-based zwitterionic hydrogels promoting endometrial repair and restoring fertility

The development of novel therapeutic approaches to facilitate endometrial repair and regeneration while preventing adhesion recurrence is a crucial research objective aimed at enhancing clinical outcomes for women with intrauterine adhesions (IUA). In this study, we introduced an injectable Alg-GMA/PTSB zwitterionic hydrogel, characterized by excellent biocompatibility, anti-protein adsorption properties, and biodegradability. In a rat model, the hydrogel significantly promoted the regeneration and angiogenesis of damaged endometrial tissue, leading to improved recovery of epithelial cells, glands, proliferation, and vascularization. Furthermore, it exhibited the ability to suppress cellular apoptosis and collagen deposition, thereby mitigating fibrosis. Additionally, the hydrogel restored the expression of estrogen/progesterone receptors and endometrial receptivity markers, contributing to enhanced embryo implantation and fertility. These findings underscore the potential of the hydrogel as a promising therapeutic strategy for addressing endometrial injury, reducing fibrosis, restoring fertility, and ultimately improving outcomes for women with IUA.

Sulfobetaine Zwitterions with Embedded Fluorocarbons: Synthesis and Interfacial Properties

We describe the preparation of a new set of fluorinated sulfobetaine (FSB) zwitterionic polymers in which fluorocarbon moieties are attached directly to the zwitterionic components. An efficient two-step modification to the conventional sulfobetaine methacrylate monomer synthesis gave access to a series of polymer zwitterions containing varying extents of fluorocarbon character. FSB methacrylates proved amenable to homo- and copolymerizations using reversible addition-fragmentation chain transfer (RAFT) conditions, affording polymers with molecular weights ranging from 5 to 20 kDa and with low molecular weight distributions. Thin films of FSB homopolymers on glass proved stable to aqueous environments and exhibited increasing hydrophobicity with fluorocarbon content, as well as remarkably large water contact angle hysteresis values that enable pinning of water droplets on hydrophobic surfaces, reminiscent of the "petal effect" found in nature. FSB-containing copolymers in aqueous media demonstrated markedly reduced oil-water interfacial tension values, even with moderate (20-50 mol %) FSB incorporation.

Characterization of Buried Interfaces of Silicone Materials in Situ to Understand Their Fouling-Release, Antifouling, and Adhesion Properties

Poly(dimethylsiloxane) (PDMS) has numerous excellent properties and is extensively used as the main component of many silicone products in a variety of research fields and practical applications such as biomedical materials, aviation, construction, electronic devices, and automobiles. Interfacial structures of PDMS and other components in silicone systems are important for such research and applications. It is difficult to probe interfacial molecular structures of buried solid-liquid and solid-solid interfaces of silicone materials due to the lack of appropriate analytical tools. In this feature article, we presented our research on elucidating the molecular structures of PDMS as well as other additives in silicone samples at buried interfaces in situ at the molecular level using a nonlinear optical spectroscopic technique, sum frequency generation (SFG) vibrational spectroscopy. SFG was applied to study various PDMS surfaces in liquid environments to understand their fouling-release and antifouling activities. SFG has also been used to study buried solid-solid interfaces between silicone adhesives and polymers, elucidating the molecular adhesion mechanisms. Our SFG studies provide important knowledge on interfacial structure-function relationships of silicone materials, helping the design and development of silicone materials with improved properties through optimization of silicone interfacial structures.

Smart salt-responsive thread for highly sensitive microfluidic glucose detection in sweat

Thread-based microfluidic colorimetric sensors have been deemed a potential tool that may be incorporated into textiles for non-invasive sweat analysis. Nevertheless, their poor performance significantly limits their practical uses in sweat glucose detection down to 20 μM. Herein, a microfluidic glucose sensing device containing a salt-responsive thread is developed for the highly sensitive detection of glucose in human sweat. By grafting a zwitterionic polymer brush-which could react to ionic strength by changing the conformation of the polymer chains from the collapsing state to the stretching state-onto the cotton thread, the salt-responsive thread was created. Compared to the pristine cotton thread, the modified thread has better ion-capture capabilities, a more noticeable swelling effect, and a higher ability to absorb water. These enable a significant enrichment of glucose when the saline solution passes through it. The salt-responsive thread was employed to construct a thread/paper-based microfluidic sensing device for the monitoring of glucose in artificial sweat, exhibiting a sensitivity of -0.255 μM-1 and a detection limit of 14.7 μM. In comparison to the pristine cotton thread-based device, the performance is significantly superior. Using a hydrophobic fabric and salt-responsive threads, a glucose-sensing headband was prepared for on-body sweat glucose monitoring. With the use of a smartphone-based image analysis system, the headband can detect the concentration of glucose in a volunteer's perspiration. Using the thread-based salt-responsive zwitterionic polymer brush might offer a novel approach to creating wearable sweat sensors with extremely high sensitivity.

Dynamic surfaces of latex films and their antifouling applications

Latex polymer particles have been widely used in industry and everyday life. For decades the fabrication of "smart" latex film from latex particles has been a great challenge due to the difficulty in the synthesis of the functional latex particles by traditional emulsion polymerization using small molecular surfactants. In this manuscript, a simple and environmentally-friendly approach to the fabrication of "smart" latex films with dynamic surfaces is reported. Latex particles with poly(n-butyl methacrylate) (PnBMA) in the cores and zwitterionic poly-3-[dimethyl-[2-(2-methylprop-2-enoyloxy) ethyl]azaniumyl]propane-1-sulfonate (PDMAPS) in the shells are synthesized by reversible addition-fragmentation chain transfer (RAFT) mediated surfactant-free emulsion polymerization. The kinetics for the emulsion polymerization is studied, and the latex particles are analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and dynamic light scattering (DLS). Latex films are prepared by casting aqueous solutions of the latex particles at temperatures above the glass transition temperature (Tg) of PnBMA. On the dried latex film, the hydrophobic PnBMA blocks occupy the top surface; after water treatment, the hydrophilic PDMAPS blocks migrate to the surface. A change in the surface hydrophilicity results in a change in the water contact angle of the latex film. A mechanism for the formation of the dynamic surface structure is proposed in this research. Antifouling applications of the latex films are investigated. Experimental results indicate that the water-treated latex film is able to efficiently inhibit protein adsorption and resist bacterial adhesion.

Diffusely Charged Polymeric Zwitterions as Loosely Hydrated Marine Antifouling Coatings

Polymeric zwitterions exhibit exceptional fouling resistance through the formation of a strongly hydrated surface of immobilized water molecules. While being extensively tested for their performance in biomedical, membrane, and, to a lesser extent, marine environments, few studies have investigated how the molecular design of the zwitterion may enhance its performance. Furthermore, while theories of zwitterion antifouling mechanisms exist for molecular-scale foulant species (e.g., proteins and small molecules), it remains unclear how molecular-scale mechanisms influence the micro- and macroscopic interactions of relevance for marine applications. The present study addresses these gaps through the use of a modular zwitterion chemistry platform, which is characterized by a combination of surface-sensitive sum frequency generation (SFG) vibrational spectroscopy and marine assays. Zwitterions with increasingly delocalized cations demonstrate improved fouling resistance against the green alga Ulva linza. SFG spectra correlate well with the assay results, suggesting that the more diffuse charges exhibit greater surface hydration with more bound water molecules. Hence, the number of bound interfacial water molecules appears to be more influential in determining the marine antifouling activities of zwitterionic polymers than the binding strength of individual water molecules at the interface.

Molecular Dynamics Simulations for Rationalizing Polymer Bioconjugation Strategies: Challenges, Recent Developments, and Future Opportunities

The covalent modification of proteins with polymers is a well-established method for improving the pharmacokinetic properties of therapeutically valuable biologics. The conjugated polymer chains of the resulting hybrid represent highly flexible macromolecular structures. As the dynamics of such systems remain rather elusive for established experimental techniques from the field of protein structure elucidation, molecular dynamics simulations have proven as a valuable tool for studying such conjugates at an atomistic level, thereby complementing experimental studies. With a focus on new developments, this review aims to provide researchers from the polymer bioconjugation field with a concise and up to date overview of such approaches. After introducing basic principles of molecular dynamics simulations, as well as methods for and potential pitfalls in modeling bioconjugates, the review illustrates how these computational techniques have contributed to the understanding of bioconjugates and bioconjugation strategies in the recent past and how they may lead to a more rational design of novel bioconjugates in the future.

Silicone-modified polyurea-interpenetrating polymer network fouling release coatings with excellent wear resistance property tailored to regulations

The invasion of alien species via marine organisms attaching to the surfaces of ship hulls is a growing problem. A number of countries have introduced corresponding regulations to combat ship biofouling. One effective way to solve this problem is to apply a fouling release coating with excellent wear resistance. In this study, a silicone-modified polyaspartic ester polyurea was synthesized by a simultaneous crosslinking polymerization. Polyaspartic ester polyurea is employed to form a tightly cross-linked network with excellent toughness and outstanding adhesion, while polydimethylsiloxane is used to form a relatively soft cross-linked network with low surface energy and surface elasticity modulus. Polyurea and silicone molecular chain lock onto each other to form interpenetrating polymer network (IPN) through their respective polymerization systems and cross-linking processes. The synergy between silicone and polyurea provides excellent mechanical properties as well as fouling release performance through the locking mechanism. This study provides a promising and universal strategy for the development of fouling release coatings with excellent wear resistance.

Silane Effects on Adhesion Enhancement of 2K Polyurethane Adhesives

With excellent properties such as great flexibility, outstanding chemical resistance, and superb mechanical strength, two-part polyurethane (2K PU) adhesives have been widely applied in many applications, including those in transportation and construction. Despite the extensive use, their adhesion to nonpolar polymer substrates still needs to be improved and has been widely studied. The incorporation of silane molecules and the use of plasma treatment on substrate surfaces are two popular methods to increase the adhesion of 2K PU adhesives, but their detailed adhesion enhancement mechanisms are still largely unknown. In this research, sum frequency generation (SFG) vibrational spectroscopy was used to probe the influence of added or coated silanes on the interfacial structure at the buried polypropylene (PP)/2K PU adhesive interface in situ. How plasma treatment on PP could improve adhesion was also investigated. To achieve maximum adhesion, two methods to involve silanes were studied. In the first method, silanes were directly mixed with the 2K PU adhesive before use. In the second method, silane molecules were spin-coated onto the PP substrate before the PU adhesive applied. It was found that the first method could not improve the 2K PU adhesion to PP, while the second method could substantially enhance such adhesion. SFG studies demonstrated that with the second method silane molecules chemically reacted at the interface to connect PP and 2K PU adhesive to improve the adhesion. With the first method, silane molecules could not effectively diffuse to the interface to enhance adhesion. In this research, plasma treatment was also found to be a useful method to improve the adhesion of the 2K PU adhesive to nonpolar polymer materials.

Sustainable Coating Based on Zwitterionic Functionalized Polyurushiol with Antifouling and Antibacterial Properties

Zwitterionic polymer coatings facilitate the formation of hydration layers via electrostatic interactions on their surfaces and have demonstrated efficacy in preventing biofouling. They have emerged as a promising class of marine antifouling materials. However, designing multifunctional, environmentally friendly, and natural products-derived zwitterionic polymer coatings that simultaneously resist biofouling, inhibit protein adhesion, exhibit strong antibacterial properties, and reduce algal adhesion is a significant challenge. This study employed two diisocyanates as crosslinkers and natural urushiol and ethanolamine as raw materials. The coupling reaction of diisocyanates with hydroxyl groups was employed to synthesize urushiol-based precursors. Subsequently, sulfobetaine moieties were introduced into the urushiol-based precursors, developing two environmentally friendly and high-performance zwitterionic-functionalized polyurushiol antifouling coatings, denoted as HUDM-SB and IPUDM-SB. The sulfobetaine-functionalized polyurushiol coating exhibited significantly enhanced hydrophilicity, with the static water contact angle reduced to less than 60°, and demonstrated excellent resistance to protein adhesion. IPUDM-SB exhibited antibacterial efficacy up to 99.9% against common Gram-negative bacteria (E. coli and V. alginolyticus) and Gram-positive bacteria (S. aureus and Bacillus. sp.). HUDM-SB achieved antibacterial efficacy exceeding 95.0% against four bacterial species. Furthermore, the sulfobetaine moieties on the surfaces of the IPUDM-SB and HUDM-SB coatings effectively inhibited the growth and reproduction of algal cells by preventing microalgae adhesion. This zwitterionic-functionalized polyurushiol coating does not contain antifouling agents, making it a green, environmentally friendly, and high-performance biomaterial-based solution for marine antifouling.

Antifouling Surfaces Based on Polyzwitterion Loop Brushes

Antifouling surfaces have attracted increasing interest in recent years due to their potential application in various fields. In this work, we report a loop polyzwitterionic coating that exhibits excellent resistance to protein adsorption. Triblock and diblock copolymers of 2-[(2-hydroxyethyl)disulfanyl]ethyl methacrylate) (HSEMA) and 2-(dimethylamino)ethyl methacrylate) (DMAEMA) were synthesized by atom-transferred radical polymerization, followed by betainization of the DMAEMA block with 1,3-propane sultone and reduction of the disulfide bond in HSEMA to yield a triblock copolymer comprising a zwitterionic poly(sulfobetaine methacrylate) (PSBMA) midblock and poly(2-sulfanylethyl methacrylate) (PSEMA) terminal blocks as well as its diblock analogue that was of the same composition as the former and half the chain length. Both copolymers adsorbed to the gold substrate via the thiol groups in the terminal PSEMA block(s), creating loop and linear PSBMA brush coatings of comparable thickness, as revealed by X-ray photoelectron spectroscopy and ellipsometry. Adsorption of bovine serum albumin and fibrinogen as model proteins from solution to these surfaces was investigated by a quartz crystal microbalance with dissipation and confocal laser scanning microscopy (CLSM), and platelet and bacterial adhesions were assessed by scanning electron microscopy and CLSM. The results demonstrate that both linear and loop polyzwitterion brushes are excellent in resisting the adsorption of the foulants, and the loop brushes are superior to the linear analogues.

Advances in Bioresorbable Triboelectric Nanogenerators

With the growing demand for next-generation health care, the integration of electronic components into implantable medical devices (IMDs) has become a vital factor in achieving sophisticated healthcare functionalities such as electrophysiological monitoring and electroceuticals worldwide. However, these devices confront technological challenges concerning a noninvasive power supply and biosafe device removal. Addressing these challenges is crucial to ensure continuous operation and patient comfort and minimize the physical and economic burden on the patient and the healthcare system. This Review highlights the promising capabilities of bioresorbable triboelectric nanogenerators (B-TENGs) as temporary self-clearing power sources and self-powered IMDs. First, we present an overview of and progress in bioresorbable triboelectric energy harvesting devices, focusing on their working principles, materials development, and biodegradation mechanisms. Next, we examine the current state of on-demand transient implants and their biomedical applications. Finally, we address the current challenges and future perspectives of B-TENGs, aimed at expanding their technological scope and developing innovative solutions. This Review discusses advancements in materials science, chemistry, and microfabrication that can advance the scope of energy solutions available for IMDs. These innovations can potentially change the current health paradigm, contribute to enhanced longevity, and reshape the healthcare landscape soon.

Biomimetic-Engineered Silicone Hydrogel Contact Lens Materials

Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in determining the function of contact lenses. Different types of contact lenses have been developed based on the chemical structure of polymers. When designing contact lenses, materials scientists consider factors such as mechanical properties, processing properties, optical properties, histocompatibility, and antifouling properties, to ensure long-term wear with minimal discomfort. Advances in contact lens materials have addressed traditional issues such as oxygen permeability and biocompatibility, improving overall comfort, and duration of use. For example, silicone hydrogel contact lenses with high oxygen permeability were developed to extend the duration of use. In addition, controlling the surface properties of contact lenses in direct contact with the cornea tissue through surface polymer modification mimics the surface morphology of corneal tissue while maintaining the essential properties of the contact lens, a significant improvement for long-term use and reuse of contact lenses. This review presents the material science elements required for advanced contact lenses of the future and summarizes the chemical methods for achieving these goals.

Antiadhesive Copolymers at Solid/Liquid Interfaces: Complementary Characterization of Polymer Adsorption and Protein Fouling by Sum Frequency Generation Vibrational Spectroscopy and Quartz-Crystal Microbalance Measurements with Dissipation Monitoring

Amphiphilic copolymers comprising hydrophilic segments of poly(ethylene glycol) and hydrophobic domains that are able to adhere to solid/liquid interfaces have proven to be versatile ingredients in formulated products for various types of applications. Recently, we have reported the successful synthesis of a copolymer designed for modifying the surface properties of polyesters as mimics for synthetic textiles. Using sum frequency generation (SFG) spectroscopy, it was shown that the newly developed copolymer adsorbs effectively on the targeted substrates even in the presence of surfactants as supplied by common detergents. In the present work, these studies were extended to evaluate the ability of the formed copolymer adlayers to passivate polyester surfaces against undesired deposition of bio(macro)molecules, as represented by fibrinogen as model protein foulants. In addition, SFG spectroscopy was used to elucidate the structure of fibrinogen at the interface between polyester and water. To complement the obtained data with an independent technique, analogous experiments were performed using quartz-crystal microbalance with dissipation monitoring for the detection of the relevant interfacial processes. Both methods give consistent results and deliver a holistic picture of brush copolymer adsorption on polyester surfaces and subsequent antiadhesive effects against proteins under different conditions representing the targeted application in home care products.

pH-Mediated Mucus Penetration of Zwitterionic Polydopamine-Modified Silica Nanoparticles

Zwitterionic polymers have emerged as promising trans-mucus nanocarriers due to their superior antifouling properties. However, for pH-sensitive zwitterionic polymers, the effect of the pH microenvironment on their trans-mucus fate remains unclear. In this work, we prepared a library of zwitterionic polydopamine-modified silica nanoparticles (SiNPs-PDA) with an isoelectric point of 5.6. Multiple-particle tracking showed that diffusion of SiNPs-PDA in mucus with a pH value of 5.6 was 3 times faster than that in mucus with pH value 3.0 or 7.0. Biophysical analysis found that the trans-mucus behavior of SiNPs-PDA was mediated by hydrophobic and electrostatic interactions and hydrogen bonding between mucin and the particles. Furthermore, the particle distribution in the stomach, intestine, and lung demonstrated the pH-mediated mucus penetration behavior of the SiNPs-PDA. This study reveals the pH-mediated mucus penetration behavior of zwitterionic nanomaterials, which provides rational design strategies for zwitterionic polymers as nanocarriers in various mucus microenvironments.

Streamlining the interface between electronics and neural systems for bidirectional electrochemical communication

Seamless neural interfaces conjoining neurons and electrochemical devices hold great potential for highly efficient signal transmission across neural systems and the external world. Signal transmission through chemical sensing and stimulation via electrochemistry is remarkable because communication occurs through the same chemical language of neurons. Emerging strategies based on synaptic interfaces, iontronics-based neuromodulation, and improvements in selective neurosensing techniques have been explored to achieve seamless integration and efficient neuro-electronics communication. Synaptic interfaces can directly exchange signals to and from neurons, in a similar manner to that of chemical synapses. Hydrogel-based iontronic chemical delivery devices are operationally compatible with neural systems for improved neuromodulation. In this perspective, we explore developments to improve the interface between neurons and electrodes by targeting neurons or sub-neuronal regions including synapses. Furthermore, recent progress in electrochemical neurosensing and iontronics-based chemical delivery is examined.

Probing Interfacial Behavior and Antifouling Activity of Adsorbed Copolymers at Solid/Liquid Interfaces

Polymers containing poly(ethylene glycol) (PEG) units can exhibit excellent antifouling properties, which have been proposed/used for coating of biomedical implants, separation membranes, and structures in marine environments, as well as active ingredients in detergent formulations to avoid soil redepositioning in textile laundry. This study aimed to elucidate the molecular behavior of a copolymer poly(MMA-co-MPEGMA) containing antiadhesive PEG side chains and a backbone of poly(methyl methacrylate), at a buried polymer/solution interface. Polyethylene terephthalate (PET) was used as a substrate to model polyester textile surfaces. Sum frequency generation (SFG) vibrational spectroscopy was applied to examine the interfacial behavior of the copolymer at PET/solution interfaces in situ and in real time. Complementarily, copolymer adsorption on PET and subsequent antiadhesion against protein foulants were probed by quartz-crystal microbalance experiments with dissipation monitoring (QCM-D). Both applied techniques show that poly(MMA-co-MPEGMA) adsorbs significantly to the PET/solution interface at bulk polymer solution concentrations as low as 2 ppm, while saturation of the surface was reached at 20 ppm. The hydrophobic MMA segments provide an anchor for the copolymer to bind onto PET in an ordered way, while the pendant PEG segments are more disordered but contain ordered interfacial water. In the presence of considerable amounts of dissolved surfactants, poly(MMA-co-MPEGMA) could still effectively adsorb on the PET surface and remained stable at the surface upon washing with hot and cold water or surfactant solution. In addition, it was found that adsorbed poly(MMA-co-MPEGMA) provided the PET surface with antiadhesive properties and could prevent protein deposition, highlighting the superior surface affinity and antifouling performance of the copolymer. The results obtained in this work demonstrate that amphiphilic copolymers containing PMMA anchors and PEG side chains can be used in detergent formulations to modify polyester surfaces during laundry and reduce deposition of proteins (and likely also other soils) on the textile.

Molecular Behavior of 1K Polyurethane Adhesive at Buried Interfaces: Plasma Treatment, Annealing, and Adhesion

One-part (1K) polyurethane (PU) adhesive has excellent bulk strength and environmental resistance. It is therefore widely used in many fields, such as construction, transportation, and flexible lamination. However, when contacting non-polar polymer materials, the poor adhesion of 1K PU adhesive may not be able to support its outdoor applications. To solve this problem, plasma treatment of the non-polar polymer surface has been utilized to improve adhesion between the polymer and 1K PU adhesive. The detailed mechanisms of adhesion enhancement of the 1K PU adhesive caused by plasma treatment on polymer substrates have not been studied extensively because adhesion is a property of buried interfaces which are difficult to probe. In this study, sum frequency generation (SFG) vibrational spectroscopy was used to investigate the buried PU/polypropylene (PP) interfaces in situ nondestructively. Fourier-transform infrared spectroscopy, the X-ray diffraction technique, and adhesion tests were used as supplemental methods to SFG in the study. The 1K PU adhesive is a moisture-curing adhesive and usually needs several days to be fully cured. Here, time-dependent SFG experiments were conducted to monitor the molecular behaviors at the buried 1K PU adhesive/PP interfaces during the curing process. It was found that the PU adhesives underwent rearrangement during the curing process with functional groups gradually becoming ordered at the interface. Stronger adhesion between the plasma-treated PP substrate and the 1K PU adhesive was observed, which was achieved by the interfacial chemical reactions and a more rigid interface. Annealing the samples increased the reaction speed and enhanced the bulk PU strength with higher crystallinity. In this research, molecular mechanisms of adhesion enhancement of the 1K PU adhesive caused by the plasma treatment on PP and by annealing the PU/PP samples were elucidated.

Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices

This review summarizes recent research on the design of polymer material systems based on biomimetic concepts and reports on the medical devices that implement these systems. Biomolecules such as proteins, nucleic acids, and phospholipids, present in living organisms, play important roles in biological activities. These molecules are characterized by heterogenic nature with hydrophilicity and hydrophobicity, and a balance of positive and negative charges, which provide unique reaction fields, interfaces, and functionality. Incorporating these molecules into artificial systems is expected to advance material science considerably. This approach to material design is exceptionally practical for medical devices that are in contact with living organisms. Here, it is focused on zwitterionic polymers with intramolecularly balanced charges and introduce examples of their applications in medical devices. Their unique properties make these polymers potential surface modification materials to enhance the performance and safety of conventional medical devices. This review discusses these devices; moreover, new surface technologies have been summarized for developing human-friendly medical devices using zwitterionic polymers in the cardiovascular, cerebrovascular, orthopedic, and ophthalmology fields.

2-Hydroxy-3-(1-(4-vinylbenzyl)imidazol-3-ium-3-yl)propane-1-sulfonate and 3-(4-Vinylbenzyl)dimethylammonio)-2-hydroxypropane-1-sulfonate as New Zwitterionic Monomers

Zwitterionic polymers emerge as very useful materials for applications in antifouling surfaces. The properties of these polymers can be tuned by variations of the chemical structure of the corresponding monomer. In this study, two zwitterionic ammonium sulfonate monomers, bearing hydroxyl function and styrenic polymerizable groups, were prepared in two steps. The two monomers were obtained using 4-vinylbenzyl chloride as the key precursor. The zwitterionic monomers were characterized by 1H NMR, 13C NMR, IR spectroscopy, and high-resolution mass spectrometry (HRMS). These two monomers enable the preparation of novel zwitterionic polymers with enhanced hydrophilicity, due to the presence of a hydroxyl group.

Zwitterionic Polypeptoids: A Promising Class of Antifouling Bioinspired Materials

Biofouling caused by protein adsorption and microbial colonization remains a great challenge in many applications. In this work, we synthesized a new type of zwitterionic polypeptoid containing carboxybetaine (CB) moieties (PeptoidCB) through thiol–ene chemistry of poly(N-allylglycine) (PNAG). The zwitterionic antifouling hydrogel was subsequently prepared by co-mixing PeptoidCB with agarose, which exhibited excellent resistance to non-specific protein adsorption and bacterial adhesion. Further, PeptoidCB-modified block copolypeptoids with amphiphilic structure were synthesized to form nanoparticles in an aqueous solution with neglected protein adsorption. The ability of PeptoidCB to resist non-specific protein adsorption and bacterial adhesion makes it a promising candidate for biomedical and industrial applications.

Fluorinated zwitterionic polymers as dynamic surface coatings

Fluorinated polymer zwitterions, when grafted from substrates, impart dynamic properties in response to fluidic environments.