Progress in Polymer Science最新文献

Hydrophilic polymers are a major class of polymers in polymer science. They are found in a broad range of applications from superabsorbers to drug-delivery. In recent years, a plethora of impactful developments in hydrophilic polymers have been reported. The present review gives an overview over these developments with a focus on frequently studied polymer types, aqueous multi-phase systems, hydrophilic block copolymer self-assembly and hydrophilic polymer particles. We cover fundamental work and concepts but also present work with high relevance for application. Finally, we give an outlook towards current challenges and future developments of the field. The further development of hydrophilic polymer is of great importance for a broad range of applications and will have a significant impact on biomedicine and every-day life.

Natural macromolecules, such as proteins and nucleic acids, display various complex functionalities in biological systems. These functionalities depend on the macromolecular structure, which is determined by the sequence of monomers as well as stereochemical factors. Over the past decade, synthetic methods have evolved to enable complete control over sequential monomer assembly. The precise control over the primary structure of abiotic macromolecules holds the promise to realize complex functionality, similar to natural biopolymers. One of the key features in biological processes involves chirality. Therefore, stereochemical considerations are a prerequisite for mimicking biological systems using synthetic polymers. Here, the progress made in the field of stereo-controlled, sequence-defined polymers is summarised. The impact of monomer sequence and stereocontrol on the physicochemical properties of polymers and their emerging functions is discussed, which underlines the importance of controlling macromolecular structure with high precision. In addition to describing synthetic methods leading to stereocontrolled and sequence-defined macromolecules, limitations and problems in their fabrication are highlighted. The review also includes examples showing how sequence and stereocontrol affect the thermal properties and degradation of polymers, which are critical in the engineering and application of polymer materials. The secondary and tertiary structures are responsible for the functions of natural polymers; therefore, the ability of abiotic macromolecules to fold and self-assemble is discussed in detail, with an emphasis on systems beyond polyamides related to protein skeletons. Furthermore, examples of functions that have been displayed by abiotic macromolecules of defined sequence and chirality are presented. The review article focuses on discrete macromolecules built based on abiotic backbones, including oligomers. In the concluding section, the collected examples are used to elucidate how monomer arrangement and stereocontrol can bring abiotic polymers to a high level of functionality, as manifested by natural macromolecules.

Block polymers comprising covalently joined polymeric segments represent a class of nanostructured, multicomponent polymeric materials. Polymerization-induced microphase separation (PIMS) is an intriguing subset that allows for simultaneous nanostructuring during block polymer synthesis. In contrast to polymerization-induced self-assembly (PISA), useful for the spontaneous formation of block polymer micelles, PIMS is well suited to fabricating monolithic block polymer materials by turning a whole polymerization mixture into a nanostructured solid. With the in situ cross-linking feature, PIMS offers a facile route to nanostructured block polymer thermosets in combination with various polymerization techniques, from emulsion polymerization to 3D printing. This review aims to provide a comprehensive overview and practical guide on PIMS by covering its historical background and mechanistic aspects and also highlighting representative material classes and applicable polymerization techniques.

Cationic polymerization is a powerful strategy for the production of well-defined polymers and advanced materials. In particular, the emergence of living cationic polymerization has enabled pathways to complex polymer architectures inaccessible before. The use of light and electricity as external stimuli to regulate cationic polymerization represents another advance with increasing applications in surface fabrication and patterning, additive manufacturing, and other advanced material engineering. The past decade also witnessed vigorous progress in stereoselective cationic polymerizations, allowing for the dual control of both the tacticity and the molecular weight of vinyl polymers towards precision polymers. In addition, in addressing the plastics pollution crisis and achieving a circular materials economy, cationic polymerization offers unique advantages for generating chemically recyclable polymers, such as polyacetals, polysaccharides, polyvinyl ethers, and polyethers. In this review, we provide an overview of recent developments in regulating cationic polymerization, including emerging control systems, spatiotemporally controlled polymerization (light and electricity), stereoselective polymerization, and chemically recyclable/degradable polymers. Hopefully, these discussions will help to stimulate new ideas for the further development of cationic polymerization for researchers in the field of polymer science and beyond.

Concern over the production, use, and disposal of polymeric materials have led to increased societal pressure to search for sustainable alternatives that are better aligned with circular economy models. In this regard, polythiourethanes are a relatively unknown polymer family with similar properties and potential applications to conventional polyurethanes, but with enhanced dynamic behavior. This dynamic behavior allows for improved recyclability and for reprocessing at milder conditions without diminishing physical or mechanical properties. In this review article, we report a comprehensive summary of the work covering polythiourethanes, which from our perspective constitute an interesting alternative to tackle environmental issues arising from plastic waste. The review first covers the main synthetic routes for the preparation of polythiourethanes with a particular focus on catalysis and non-isocyanate routes. Subsequently, the thermo-mechanical and optical properties of polythiourethane materials are discussed, highlighting the similarities and differences concerning polyurethanes. Following this, the opportunities arising from the enhanced dynamic character of the thiourethane bond are considered, emphasizing works covering the chemical recycling and/or reprocessing of polythiourethane thermosets. Finally, we discuss their use for advanced applications and current advanced manufacturing processes and highlight our perspective on the future challenges and opportunities offered by polythiourethane materials.

Magnetic resonance imaging (MRI) is recognized as the most powerful clinical imaging modality due to its ability to produce detailed three-dimensional anatomical images and high spatial resolution in a non-invasive manner without the use of harmful radioactive nuclides or ionizing radiation. Conventional small molecule contrast agents (CAs) for MRI, such as paramagnetic transition metal ion chelates or iron oxide nanoparticles, are limited by lower relaxivity, shorter blood circulation time and their potential toxic effects. Functional polymers capable of being detected by MRI have therefore become attractive, offering the unique advantage of pre-design due to their chemical flexibility, structural diversity, and tailoring of properties. Reversible addition-fragmentation chain-transfer (RAFT) polymerization is a powerful tool that not only enables the precise formation of macromolecular building blocks with complex structures and functions, but also provides a direct method for preparation of polymeric nanoparticles with multiple morphologies suitable for biomedical applications. In addition, when combining RAFT polymers with inorganic/metallic complex nanocomposites, the polymer provides the ability to encapsulate therapeutic molecules, thereby combining diagnostic and therapeutic functions in what is known as a theranostic nanomedicine. In this review, we highlight recent advances in the development of multifunctional polymers as MRI CAs designed and prepared by RAFT polymerization and their performance in diagnosis and treatment of disease. In addition, the review will address the challenges and future opportunities for RAFT-mediated MRI-based theranostics in guiding the treatment of diseases including malignant tumors.

Triboelectric nanogenerators (TENGs), a nascent field in energy conversion technologies, provide a novel approach to producing electrical energy from mechanical motion in the surrounding environment.Polymers play a key role in the functioning of TENGs through their exceptional triboelectric properties, with most triboelectric active materials being polymeric with negative affinity potential. Since there are many scientific issues that are not well understood yet regarding the working mechanism and fundamental issues regarding the role of polymers in TENGs, this review covers TENG fundamentals and effects of environmental parameters and provides a deep analytical analysis of important literature studies of TENGs. Although TENGs generate high voltage, their current generation is usually in the microamp range. Modifying polymer dielectric materials has been much investigated to enhance the output performance of TENGs. This article provides a comprehensive review of various polymer modification categories and associated performance enhancement with an analysis and comparison of research results to help grasp the big picture on the role of polymer modification on TENG performance. Specifically, the source of triboelectrification and updated knowledge about their working principle, and the quantified comparison of triboelectric material are discussed. Then physical nano and microstructure and the effect of TENG material shape on the output are brought into the discussion. Equally, the important role of chemical modification of triboelectric active polymer by way of categorization of methods and their effect on electricity generation is put under focus. In order to enhance the triboelectric negativity of polymer properties, it is useful to introduce chemical groups with high negativity, such as halogens. This can be achieved through several methods, including using a sulfur backbone or casting fluorinated self-assembly monolayers (SAMs), and the impact on TENGs' performance is explored. Furthermore, the addition of fillers to polymers is a proven technique for increasing their dielectric constant, which is emphasized as particularly significant.

The past decades have witnessed the rapidly growing interest in polymer films as the most commonly used packaging material due to their lightweight, versatility, low cost, and ease of manufacturing. However, there is a noticeable mismatch between the demanding requirements of various oxygen- or humidity-sensitive commodities and the poor barrier properties of single-component polymer films, thus giving rise to food spoilage, drug failure, as well as corrosion damage of electronic devices. In this review, we provide an in-depth introduction on the most promising strategies for developing high barrier polymer packaging films, including surface coating, polymer blending, and polymer nanocomposites. Specifically, the types of surface coatings, the dispersed phase morphology in polymer blends, the main factors for polymer nanocomposites containing large-aspect-ratio nanoplatelets, their dispersion morphology, the interfacial structure, and the crystalline structure of the matrix polymers can be tailored to maximize the gas barrier performance. Also, current challenges and perspectives for future development of high barrier polymer packaging materials are proposed. The new insight into the relationship between polymer processing, microscopic architecture, and barrier properties of polymer materials are expected to provide a valuable guide for developing high-barrier polymer packaging materials.

Polymer coatings of nanometric thickness are about to enter in everyday life as part of a wide range of applications such as protective layers, stimuli-responsive membranes or as components of flexible electronics devices. In the past 30 years, these polymer nanomaterial systems have been at the center of research interest due to the opportunities to control relevant material properties like the phase transition temperature, viscosity, permeability, or thermal expansion by variation of the film thickness. One of the key factors responsible for the deviation from bulk behavior is known as 1D confinement that describes the increasing impact of interfacial layers when reducing film thickness. This review provides a comprehensive discussion of the role of the free surface at the boundary with air and the interfacial layer in proximity of a supporting substrate on the crystallization of thin polymer films. First, the dynamics of polymers near the free surface and its impact on the crystallization of films is discussed. Subsequently, the effect of solid substrates on crystallization in thin films is elaborated, including the formation of irreversible adsorption layers, alteration of crystalline structure and the kinetics of crystallization. Subsequently, the competition between surface and interface effects on the formation of ordered structures in thin polymer films is discussed. A perspective on challenges and opportunities in the field of thin film crystallization is provided to inspire future research and development in the field. This review thus provides an up-to-date analysis of current understanding of crystallization of polymer glasses under 1D confinement, aimed at supporting the manipulation and control of the properties of polymer-based nanodevices.

Polymers and polymer composites with advanced functions have attracted great attention following the development of modern science and technologies. Nevertheless, damages of microstructures and variations of chemical constitutes are inevitably induced during their manufacturing and operation, causing undesired attenuation or even loss of functionalities. To address the problems, self-healable functional polymeric materials, which focus on autonomous restoration of non-structural functionalities for improving the lifespan and durability, have emerged in recent years as a huge surge of interest because of their apparent potential benefits. As dictated by the diverse working principles of the individual functionalities, the technical advance of self-healing functional polymers and composites exhibits distinct characteristics from that of self-healing structural materials specializing in strength recovery. This review summarizes the state-of-the-art achievements in the field, and discusses the common features and issues in most of the reported self-healing functional materials including healable electroconductive, thermally conductive, dielectric, optically transparent, superhydrophobic, superhydrophilic, and power conversion and storage related polymers. The review will subsequently discuss (i) the damage modes relating to different causes, (ii) the mechanisms of self-healing based on chemical and physical methodologies, and (iii) molecular level design schemes and synthesis strategies for self-healing functional polymeric materials. The advantages and inadequacies of representative works are discussed, and the critical challenges and opportunities for future research are highlighted. It is hoped that the present article would inspire more innovative explorations of self-healing functional polymeric materials, as well as promote their practical application.