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Molecular imprinting technology (MIT) aims to prepare polymers with tailor-made binding sites for the templates in shape, size and functional groups. However, many disadvantages of ...traditional MIT lead to some unsatisfactory results. Recently, surface molecular imprinting technique (SMIT) has aroused extensive attention and been applied in many fields, such as sensors, separation and purification, catalysis and biomedical areas owing to the desired selectivity, reduction of “embedding” phenomenon, fast mass transfer rate and binding kinetics. With the rapid development of SMIT, it faces a number of challenges, involving pure templates obtained, the higher cost of using noble metals, unclear recognition mechanism, low solubility of the templates in solvents, etc., which limit its practical applications in various aspects. This paper briefly reviews current status of the SMIT, particularly emphasis on the preparation of surface molecularly imprinted polymers (SMIPs, including interactions between templates and monomers, solid matrixes and synthetic strategies) and significant applications on sensors, separation and purification, catalysis and biomedical areas. Furthermore, some still existing challenges and future prospects in this research area are also highlighted.
One hundred years ago Hermann Staudinger was strongly criticized by his scientific peers for his macromolecular hypothesis, but today it is hard to imagine a world without polymers. His hypothesis ...described polymers as macromolecules composed of large numbers of structural units connected by covalent bonds. In the 1990s the concept of supramolecular polymers emerged in the scientific literature as discrete entities of large molar mass comparable to that of classical polymers but built through non-covalent bonds among monomers. Supramolecular polymers exist in biological systems, and potentially blend the physical properties of covalent polymers with unique features such as high degrees of internal order within the polymeric structure, defined shapes, and novel dynamics. This trend article provides a summary of seminal contributions in supramolecular polymerization and provides recent examples from the Stupp laboratory to demonstrate the potential applications of an exciting class of materials composed fully or partially of supramolecular polymers. In closing, we provide our perspective on future opportunities provided by this field at the onset of a second century of polymers. It is our objective here to demonstrate that this second century could be as prosperous, if not more so, than the preceding one.
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•Current review on Self-healing polymers based on Diels-Alder cycloaddition.•Discussing healing thermodynamics for physical and chemical changes during healing.•Deeper insight on use of advanced ...analytical/spectroscopic/modelling techniques.•Use of multifunctional healing mechanisms for advanced engineering applications.•Future scope of DA polymers based on better commerciality and green chemistry.
The ability of artificial materials to be healed efficiently, mimicking the living organisms, exhibits a great deal of potential advantages that can revolutionise the operation and maintenance of materials used in various applications. Such self-healable smart materials have been extensively researched in the last few decades, leading to the development of different physical and chemical synthesis approaches. Among these methods, chemical techniques based on reversible cycloadditions or disulfide bonding provide obvious advantages in terms of repeatability, which holds prime importance in determining the commerciality of the healing approach. This review compiles the recent advances in the field of self-healing polymers where the healing ability is introduced by reversible cycloaddition reactions while focusing mainly on the Diels-Alder (DA) reaction. DA is a 4 + 2 cycloaddition reaction where diene and dienophile pairs are used to fabricate thermally reversible crosslinked networks. These covalent bonds provide the necessary reversibility to the healing matrix and impart the desired strength to the polymeric material. There is a considerable body of recent literature where DA bonding has been employed either on its own or along with other healing mechanisms to impart self-healing to polymers. However, lack of a systematic review discussing these works makes it difficult for a beginner to cope with advancements in this field. Most early studies have focused on the healing stimuli and efficiency of healing in polymers but with this review, we would like to explore the healing thermodynamics governing the rupture–repair process in DA polymers along with the use of advanced spectroscopic techniques to study them and their applicability in thermosets, epoxy resins, biopolymers, and polymer nanocomposites. Novel applications for such advanced functional polymers, multifunctional healable polymers, and the outlook for future research, opportunities and challenges in the area are also discussed.
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The production of polybenzoxazines from natural renewable materials has attracted interest because of the environmental impacts caused by conventional petroleum-based materials. This ...is a comprehensive review of benzoxazine resins using natural renewable raw materials. Substances, extracted from the nature, or converted from agro-waste or byproducts of the environmental industry, are utilized to synthesize benzoxazine monomers, and their polymerization behavior and the properties of polymers have been discussed. Diversity of structural features and unique functions make natural renewable materials potential candidates for high-performance benzoxazine resins. Abundance, low price, multi-approach available bio-based waste are the driving force of future applications. Papers on the manufacturing of polybenzoxazine blends and composites with renewable fillers and their applications have also been reviewed.
Photosensitizer delivery is prerequisite for successful photodynamic therapy (PDT), and many photosensitizers have been developed and investigated in in vitro and in vivo studies 1. In general, ...hydrophobic photosensitizers can efficiently interact with biological components including cell membrane via hydrophobic interaction and exhibit high cellular uptake, inducing strong PDT effects in in vitro conditions.
However, in in vivo conditions, such hydrophobic photosensitizers also interact with normal cells and tissues as well as target tumours, which causes unfavourable photochemical damage. On the other hand, hydrophilic photosensitizers avoid unfavourable interaction with biological components and their retention in the skin, reducing photosensitivity which is one of the side effects in PDT. However, the compromised interaction leads to low cellular uptake and PDT effects. Thus, it is difficult to develop photosensitizers that can induce strong PDT effects without showing severe photochemical damage to normal tissues.
In this study, to integrate these conflicting properties of hydrophobic/hydrophilic photosensitizers, we developed a functional polymer exerting isothermal hydrophilic-to-hydrophobic phase transition in response to mildly acidic pH in tumours 2. The backbone of the polymer was a poly(N-isopropylacrylamide) derivative, which is well known to show lower critical solution temperature, and its side chain was modified with hydrophilic pH-cleavable moieties. The polymer termed P(NIPAAm/AIPAAm-PMM) showed hydrophilicity in a physiological condition (37°C, pH 7.4); however, in a tumour microenvironment-like condition (37°C, pH ≤ 6.9), P(NIPAAm/AIPAAm-PMM) exhibited hydrophobicity by detaching the hydrophilic moieties from the side chain. Owing to this pH-responsive hydrophilic-to-hydrophobic phase transition, the polymer exerted efficient cellular uptake in a pH-responsive manner. We then conjugated a phthalocyanine-based photosensitizer (IRDye 700DX) with the polymer and examined the potential of the polymer for PDT. In in vitro study, The photosensitizer-polymer conjugate exhibited strong PDT effects at acidic pH because of the aforementioned pH-responsive cellular uptake. In in vivo study, the photosensitizerpolymer conjugate efficiently accumulated within tumours in mice after intravenous injection and accomplished significantly enhanced PDT effects. Our results indicate that the control of hydrophilicity and hydrophobicity may be a promising approach to develop new photosensitizers for successful PDT.
Polymerizations of Activated Alkynes He, Benzhao; Huang, Jiachang; Liu, Xinyue ...
Progress in polymer science,
March 2022, 2022-03-00, Volume:
126
Journal Article
Peer reviewed
The exploration of activated alkyne-based polymerizations recently has attracted considerable attention for their huge potentials in a diverse range of real-life applications from polymer chemistry ...to materials science, supramolecular science, and biomedicine and pharmaceutical chemistry. In this review, we summarized the recent achievements in activated alkyne-related polymerizations and the properties and applications of the prepared polymers. Through representative examples, we elucidated the essential construction principle, developing strategy and optimization approach of each polymerization and illustrated the diverse and appealing properties and applications of the resulting polymers to offer guidance for the development of new polymerization and promote the development of polymeric materials with more superior and innovative properties and applications.
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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.
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CO2 is one of the major environmental pollutants and its mitigation is attracting huge attention over the years due to continuous increase in this greenhouse gas emission in the atmosphere. Being ...environmentally hazardous and plentiful presence in nature, CO2 utilization as C1 resource into fuels and feedstock is very demanding from the green chemistry perspectives. To accomplish this CO2 utilization issue, functional organic materials like porous organic polymers (POPs), covalent organic frameworks (COFs) as well as organic-inorganic hybrid materials like metal-organic frameworks (MOFs), having characteristics of large surface area, high thermal stability and tunability in the porous nanostructures play significant role in designing the suitable catalyst for the CO2 hydrogenation reactions. Although CO2 hydrogenation is a widely studied and emerging area of research, till date review exclusively focused on designing POPs, COFs and MOFs bearing reactive functional groups is very limited. A thorough literature review on this matter will enrich our knowledge over the CO2 hydrogenation processes and the catalytic sites responsible for carrying out these chemical transformations. We emphasize recent state-of-the art developments in POPs/COFs/MOFs having unique functionalities and topologies in stabilizing metallic NPs and molecular complexes for the CO2 reduction reactions. The major differences between MOFs and porous organics are critically summarized in the outlook section with the aim of the future benefit in mitigating CO2 emission from ambient air.
We highlighted recent state-of-the art catalyst developments in POPs/COFs/MOFs for chemical hydrogenation of CO2 and their potential future benefits in mitigating CO2 emission from ambient air. Display omitted
•CO2 hydrogenation over functional porous materials as catalytic supports•Catalytic conversion of CO2 to mostly HCOOH over metal containing porous organic polymers•MOFs are used as heterogeneous catalyst for the synthesis of methanol, methane and lower olefins and formic acid from CO2.•Critical needs in the design of MOFs/COFs/POPs for CO2 hydrogenation reaction are highlighted.
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Owing to the natural abundance, variety of structural features, and highly specific functions, natural monomers render themselves as potential candidates for production of high ...performance functional polymers. The emerging concept of the biorefinery and development of new biosynthetic routes to synthesize a versatile and broad spectrum of natural monomers and polymers continues to gain momentum. The production of high quality polymers from renewable feedstocks requires innovative chemical modifications and catalytic transformations to achieve higher yields in an efficient manner. A fresh look into monomers available from natural resources such as terpenes, rosin, glycerol, furans, tannins, suberin, their derivatives and miscellaneous monomers may inspire future applications with impactful biobased materials. There are also many areas that require urgent discussion and review pertaining to recent developments in the field; this includes monomer sources that give molecules having special structural features. In particular, cardanol, a naturally occurring low-molecular-weight compound is unique as it contains a phenolic head group and a hydrocarbon chain with different degrees of unsaturation. This molecule possesses functional groups that are amenable for classical chemical modification, which is instrumental in developing a wide range of functional monomers and polymers. A large number of soft and hard materials have been developed from cardanol-based monomers. During the past, a large number of industrial grade materials have been developed from plant-based monomers, including development from microbial and fermentation processes (i.e. lactic acid). This review provides a comprehensive study and survey on recent developments on monomers and polymers derived from urushiol and cardanol based monomers and polymers, vegetable oil-based monomers and polymers, microbially produced monomers and polymers. These all represent emerging fronts giving a vast scope while highlighting important potential material and reagent opportunities.
The past decade has witnessed tremendous advances in the synthesis of polymers that contain elements from the main groups beyond those found in typical organic polymers. Unique properties that arise ...from dramatic differences in bonding and molecular geometry, electronic structure, and chemical reactivity, are exploited in diverse application fields. Herein we highlight recent advances in inorganic backbone polymers, discuss how Lewis acid/base functionalization of polymers results in unprecedented reactivity, and survey conjugated hybrids with unique electronic structures for sensor and device applications.
Polymers go main group! This Review shows how the incorporation of the full range of available main‐group elements into polymers leads to new functional hybrid materials with potential use in diverse application fields ranging from advanced elastomers, responsive gels, biodegradable materials, to organic electronics, imaging agents, sensors, and supported catalysts.
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