Supramolecular polymers, polymeric systems beyond the molecule, have attracted more and more attention from scientists due to their applications in various fields, including stimuli-responsive materials, healable materials, and drug delivery. Due to their good selectivity and convenient enviro-responsiveness, crown ether-based molecular recognition motifs have been actively employed to fabricate supramolecular polymers with interesting properties and novel applications in recent years. In this tutorial review, we classify supramolecular polymers based on their differences in topology and cover recent advances in the marriage between crown ether-based molecular recognition and polymer science.
New sulfonated poly(arylene ether sulfone) copolymers with high molecular weights were successfully synthesized with controlled degrees of disulfonation of up to 70 mol % via the direct copolymerization of sulfonated aromatic dihalides, aromatic dihalides, and one of four structurally distinct bisphenols. The disodium salts of the 3,3Ј-disulfonated-4,4Ј-dichlorodiphenyl sulfone and 3,3Ј-disulfonated-4,4Ј-difluorodiphenyl sulfone comonomers were synthesized via the sulfonation of 4,4Ј-dichlorodiphenyl sulfone or 4,4Ј-difluorodiphenyl sulfone with 30% fuming sulfuric acid at 110°C. Four bisphenols (4,4Ј-bisphenol A, 4,4Ј-bisphenol AF, 4,4Ј-biphenol, and hydroquinone) were investigated for the syntheses of novel copolymers with controlled degrees of sulfonation. The composition and incorporation of the sulfonated repeat unit into the copolymers were confirmed by 1 H NMR and Fourier transform infrared spectroscopy. Solubility tests on the sulfonated copolymers confirmed that no crosslinking and probably no branching occurred during the copolymerizations. Tough, ductile films were solvent-cast that exhibited increased water absorption with increasing degrees of sulfonation. These copolymers are promising candidates for high temperature protonexchange membranes in fuel cells, which will be reported separately in part II of this series.
The topology of a polymer has a significant influence on its properties and functions, both in bulk and in solution. Therefore, the discovery of efficient methods to control polymer topology is very important.[1] The introduction of non-covalent interactions into traditional covalent polymers represents a novel approach for the control of polymer topologies, and has allowed the incorporation of reversible and switchable functionality into different macromolecular architectures.[2] However, this strategy usually requires the integration of specific molecular recognition motifs into polymer chains; such an approach suffers from problems such as the availability of suitable monomers and the poor efficiency of polymerization techniques that are tolerant to functional groups on the polymer. Conversely, supramolecular polymers that are assembled from low molecular weight monomers by non-covalent interactions, such as hydrogen bonding, [3] metal coordination, [4] and host-guest interactions, [5] have demonstrated traditional polymeric properties and are an important resource in the development of stimuliresponsive dynamic materials. [6] Until now, efforts to control the topology of supramolecular polymers have mainly been concerned with the conversion between the large-sized species and their corresponding monomers/oligomers; comparatively little effort has been devoted to the transformation between supramolecular polymers of different topologies. The desired recognition motifs can be conveniently introduced into the low-molecular-weight-monomers, thus avoiding the problems commonly associated with covalently linked polymer backbones, and thus leading to a more effective method for switching between different architectures. Herein, we present reversible switching between linear and cross-linked supramolecular polymers.That biological systems utilize multiple-interaction selfassembly to afford hierarchical and multifunctional systems [7] has inspired the development of multiple-code artificial supramolecular analogues.[8] In particular, we have assembled dynamic supramolecular polymers that have linear or crosslinked topologies using bimodal non-covalent recognition motifs, host-guest and metal-ligand interactions. As bis(metaphenylene)-[32]crown-10-based cryptands form complexes with paraquat derivatives much more strongly than bis-(meta-phenylene)-[32]crown-10 (BMP32C10), [9] the cryptand-paraquat complementary interaction was incorporated into monomer 1 for the efficient construction of its linear supramolecular polymer (Scheme 1). BMP32C10-paraquatbased analogue 2 was also synthesized to compare the effect of the host-guest binding ability on the properties of the resulting supramolecular aggregates.The role of 1,2,3-triazole as a ligand for coordination with transition metals has been well reported.[10] Recently, Astruc et al. reported that when [PdCl 2 (PhCN) 2 ] (3) acts as the metal precursor, palladium(II) complexes could be formed with two trans triazole ligands (Scheme 1).[10c] The strategy was successf...
Innovative technologies are highly pursued for the detection and avoidance of counterfeiting in modern information society. Herein, we report the construction of photo-responsive supramolecular polymers toward fluorescent anti-counterfeit applications, by taking advantage of multicycle anthracene‒endoperoxide switching properties. Due to σ-metalation effect, photo-oxygenation of anthracene to endoperoxide is proceeded under the mild visible light irradiation conditions, while the backward conversion occurs spontaneously at room temperature. Supramolecular polymers are formed with cooperative nucleation‒elongation mechanism, which facilitate fluorescence resonance energy transfer process via two-component co-assembly strategy. Fluorescence resonance energy transfer efficiency is delicately regulated by either light-triggered anthracene‒endoperoxide conversion or vapor-induced monomer–polymer transition, leading to high-contrast fluorescent changes among three different states. On this basis, dual-mode anti-counterfeiting patterns have been successfully fabricated via inkjet printing techniques. Hence, cooperative supramolecular polymerization of photo-fluorochromic molecules represents an efficient approach toward high-performance anti-counterfeit materials with enhanced security reliability, fast response, and ease of operation.
Abstract-Wireless sensor networks (WSNs) have been applied to many applications since emerging. Among them, one of the most important applications is Sensor Data Collections, where sensed data are collected at all or some of the sensor nodes and forwarded to a central base station for further processing. In this paper, we present a survey on recent advances in this research area. We first highlight the special features of sensor data collection in WSNs, by comparing with both wired sensor data collection network and other WSN applications. With these features in mind, we then discuss the issues and prior solutions on the utilizations of WSNs for sensor data collection. Based on different focuses of previous research works, we describe the basic taxonomy and propose to break down the networked wireless sensor data collection into three major stages, namely, the deployment stage, the control message dissemination stage and the data delivery stage. In each stage, we then discuss the issues and challenges, followed by a review and comparison of the previously proposed approaches and solutions, striving to identify the research and development trend behind them. In addition, we further discuss the correlations among the three stages and outline possible directions for the future research of the networked wireless sensor data collection.
The bottom-up self-assembly of donor-acceptor (D-A) units has received tremendous attention in recent years. Charge-transfer interactions, which are inherently embedded in D-A pairs, have suffered from some disadvantages such as erratic arrangements and weak binding affinity, thus hampering the precise arrangement of D-A units into long-range-ordered supramolecular polymers. To address this issue, a feasible protocol is to incorporate D-A units into molecular tweezers/guest recognition motifs, which concurrently feature high complexation directionality, strong binding affinity and stimuli-responsiveness. In this tutorial review, we have summarized the recent advances on the tweezering directed formation of D-A-type supramolecular polymers, with particular emphasis on the design principles of monomers and macroscopic behaviors of supramolecular polymers, together with future challenges in this research field.
Supramolecular polymers are constructed based on the novel bis[alkynylplatinum(II)] terpyridine molecular tweezer/pyrene recognition motif. Successive addition of anthracene as the diene and cyano-functionalized dienophile triggers the reversible supramolecular polymerization process, thus advancing the concept of utilizing Diels-Alder chemistry to access stimuli-responsive materials in compartmentalized systems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.