Hydrogen bonds (H-bonds) constitute highly relevant structural units of molecular self-assembly. They bridge biological and synthetic sciences, implementing dynamic properties into materials and ...molecules, not achieved via purely covalent bonds. Phase segregation on the other hand represents another important assembly principle, responsible for, e.g., cell compartimentation, membrane-formation, and microphase segregation in polymers. Yet, despite the expanding elegant synthetic strategies of supramolecular polymers, the investigation of phase behavior of macromolecules driven by H-bonding forces still remains in its infancy. Compared to phase segregation arising from covalently linked block copolymers, the generation of phase segregated nanostructures via supramolecular polymers facilitates the design of novel functional materials, such as those with stimuli-responsive, self-healing, and erasable-material properties. We here discuss the phase segregation of H-bonding polymers in both the solution and solid state, wherein the molecular recognition elements are based on multiple H-bonding moieties, such as thymine/2,6-diamino-pyridine (THY/DAP), thymine/diamino triazine (THY/DAT), and barbiturate/Hamilton wedge (Ba/HW) elements. The specific aggregation of a series of different H-bonding polymers in solution, both linear and dendritic polymers, bearing heterocomplementary H-bonding moieties are described, in particular focusing on the issue of phase segregation. The exploitation of H-bonded supramolecular dendrons with segregating polymer chains leads to the formation of three-phase segregated hierarchical micelles in solution, purely linking the components via H-bonds, in turn displaying a versatile spectrum of segregated morphologies. We also focus on segregation effects of H-bonded amorphous and crystalline polymers: thus the formation of nanostructures, such as disordered micelles and well-ordered body centered cubic (BCC) packed spheres from telechelic polymers bearing H-bonding moieties at the chain ends is observed. Finally, we discuss the discovery of novel functional microphase separated self-healing supramolecular architectures, illustrating dynamic and self-healing properties with an almost complete recovery of the initial mechanical performances healing within 24h at 30 °C. Collectively, our studies prove that phase segregation in H-bonding polymers is an important principle, capable to generate nanostructures and dynamic properties not achieved in covalently linked polymers. The results discussed illustrate that a rational architectural design within H-bonding polymer systems in interplay with phase segregation in both the amorphous and crystalline state opens perspectives to develop artificial supramolecular systems approaching the level of complexities and properties present in nature’s biomaterials.
Integrating self‐healing capability into supramolecular architectures is an interesting strategy, and can considerably enhance the performance and broaden the scope of applications for this important ...class of polymers. Herein we report the rational design of novel V‐shaped barbiturate (Ba) functionalized soft–hard–soft triblock copolymers with a reversible supramolecular healing motif (Ba) in the central part of the hard block, which undergoes autonomic repair at 30 °C. The designed synthesis also offers a suitable macromolecular building block to further self‐assemble with heterocomplementary α,ω‐Hamilton wedge (HW) functionalized polyisoprene (PI; HW‐PI‐HW), resulting in an H‐shaped supramolecular architecture with efficient self‐healing capabilities that can recover up to around 95 % of the original mechanical performance at 30 °C within 24 h.
Unbreakable: Incorporation of a barbiturate unit in the center of soft–hard–soft triblock copolymers results in V‐shaped supramolecular architectures with multiple self‐healing properties. Self‐assembly with the heterocomplementary α,ω‐Hamilton wedge functionalized polyisoprene results in an H‐shaped supramolecular architecture that can recover around 95 % of its original performance after 24 h at 30°C.
A novel dual-ligand reagent (2Z)-
N,
N′-bis(2-aminoethylic)but-2-enediamide, was synthesized and applied to prepare metal ion-imprinted polymers (IIPs) materials by ionic imprinted technique for ...selective solid-phase extraction (SPE) of trace Cd(II) from aqueous solution. In the first step, Cd(II) formed coordination linkage with the two ethylenediamine groups of the synthetic monomer. Then the complex was copolymerized with pentaerythritol triacrylate (crosslinker) in the presence of 2,2′-azobisisobutyronitrile as initiator. Subsequently, the imprinted Cd(II) was completely removed by leaching the dried and powdered materials particles with 0.5
M HCl. The obtained IIPs particles exhibited excellent selectivity for target ion. The distribution ratio (
D) values of Cd(II)–IIPs for Cd(II) were greatly larger than that for Cu(II), Zn(II) and Hg(II). The relative selective factor (
α
r) values of Cd(II)/Cu(II), Cd(II)/Zn(II) and Cd(II)/Hg(II) were 25.5, 35.3 and 62.1. The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cd(II) was 32.56 and 6.30
mg
g
−1, respectively. Moreover, the times of adsorption equilibration and complete desorption were remarkably short. The prepared Cd(II)–IIPs were shown to be promising for solid-phase extraction coupled with inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of trace Cd(II) in real samples. The precision (R.S.D.) and detection limit (3
σ) of the method were 2.4% and 0.14
μg
L
−1, respectively. The column packed with Cd(II)–IIPs was good enough for Cd(II) separation in matrixes containing components with similar chemical behaviour such as Cu(II), Zn(II) and Hg(II).
Adhesive bonding to diverse substances is vital to a great number of the established, cutting-edge and emerging applications. We have witnessed, in the last few years, the transformative progress in ...achieving robust adhesive bonding and tunable debonding behavior, which mostly employing the supramolecular forces. Among the diverse supramolecular forces, the contribution of hydrogen-bonds (H-bonds) to adhesives, on the modality of directionality, selectivity and sensitivity, can function as nano-scaled bonding agents for improved interfacial interactions, thus paved novel perspectives to the design and creation of glue materials with outstanding performance. On account of the dynamic and reversible feature, a characteristic principally determined for H-bonding (macro)molecules could be employed as adhesive platform for affording outstanding attaching, connecting and on demand disconnecting, arising from the combination of adhesion/cohesion process via H-bonding interactions and the responsive characteristics. Thus, H-bonded adhesives with abundant diverse molecular configuration furnish a rich toolbox that can fulfill universal yet specific needs with unique advantages, demonstrating great opportunities for fundamental researches and practical applications. Herein we outline and summarize the design and creation of H-bonded adhesives, responsive attaching/detaching, and applications in advanced materials. We propose the guidance for further designing H-bonded adhesives, in concert with biomedical science, physics, mechanical and electric, informatics or robotics of promising future.
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Heterotelechelic poly(n-butyl acrylate)s (PnBuA) bearing two different and complementing supramolecular groups (namely, barbiturate (Ba) and the Hamilton wedge (HW)) at their α-end and ω-end ...(Ba–PnBuA–HW) were prepared by a combination of the reversible addition–fragmentation chain transfer (RAFT) process and the thio–bromo click reaction. The successful synthesis of the heterotelechelic H-bonding polymer Ba–PnBuA–HW (M n,NMR = 7700 g/mol, M n,SEC = 7500 g/mol, PDI = 1.25) was proven by a combination of 1H NMR and MALDI-TOF mass spectrometry. Self-assembly of the resulting heterotelechelic H-bonding polymers (Ba–PnBuA–HW) in a head-to-tail fashion driven by multiple H-bondings in solution and in the bulk was proven by temperature-dependent 1H NMR, concentration-dependent DOSY NMR studies, and rheological measurements.
We report an original strategy toward the straightforward preparation of precisely defined telechelic H-bonding polymers and the generation of supramolecular block copolymers thereof. Making use of ...an α,ω-functionalized symmetrical trithiocarbonate bearing thymine groups at both chain ends, a series of heterocomplementary H-bonding polymers were effortlessly generated by RAFT polymerization in a one step process. The resulting telechelic macromolecules selectively interacted with heterocomplementary α-DAP-functionalized chains to afford supramolecular block copolymers in solution and in bulk. These self-assemblies were evidenced by 1H NMR and rheological measurements. As a consequence of these associations, whereas non functional homopolymer blends tended to microphase separate as observed by AFM analysis, H-bonding homopolymer blends exhibited homogeneous microstructures in accord with the formation of supramolecular block copolymers promoting the stabilization of the interface between the polymers.
The field of anticancer nanomedicine seeks to boost the arsenal’s exploitation with intelligent performance. One opportunistic choice comes from the fabrication of amphiphilic polymer micelles that ...are reversibly crosslinked. Here, hydrogen-bond (H-bond)-driven core-crosslinked supramolecular polymer micelles (FUS/ICG@PEDD) are constructed, co-loading α,ω-functionalized symmetrical H-bonding prodrug 5-fluorouracil-acetic acid–SS–5-fluorouracil-acetic acid (FUS) and a dual photothermal/photodynamic agent (indocyanine green, ICG). Such core-crosslinked nanomedicine is characterized by enhanced drug loading content, crosslinking-prompted stability, pH-responsive charge reversal, and smart drug release, which can facilitate the engineering of synergistic chemo/photothermal/photodynamic therapies (CT/PTT/PDT). To do so, an amphiphilic diblock copolymer, PEG-b-P(DAPA-co-DEAEMA) (denoted as PEDD), is developed to serve as a drug delivery vehicle, with hydrophilic PEG poly(ethylene glycol) and hydrophobic P(DAPA-co-DEAEMA) poly(diaminopyridine acrylamide-co-2-(diethylamino)ethyl methacrylate, bearing randomly dispersed dual functionalities: pH-responsive charge-reversal DEAEMA and H-bonding DAP motifs. Thanks to the specific DAP/FUS H-bonding interactions and two-terminal FU structure of the prodrug, core-crosslinked nanomedicine FUS/ICG@PEDD is thus enabled. In vitro and in vivo investigations indeed reveal remarkable antitumor efficacy. We believe that such H-bonded nanomedicines can fuel the development of intelligent nanomedicines with value in cancer therapy.
Supramolecular miktoarm stars (AB2 type) composed of poly (methyl methacrylate)-polystyrene2 (PMMA-PS2), poly(isoprene)-polystyrene2 (PI-PS2), and poly(vinyl acetate)-polystyrene2 (PVAc-PS2) were ...successfully synthesized by assembling reversible addition−fragmentation chain transfer (RAFT)-polymerized chains bearing hydrogen-bonding heterocomplementary associating units. To this end, thymine and diaminopyridine-functionalized chain transfer agents were designed to efficiently mediate the polymerization of vinyl acetate, methyl methacrylate, isoprene, and styrene. The selective associations of the resulting hydrogen-bonding macromolecular building blocks PVAc/PS, PI/PS, and PMMA/PS were demonstrated by 1H NMR in CDCl3 solutions. Miktoarm stars formation in the bulk was also confirmed by transmission electronic microscopy.
Complete cancer cure and healing are still difficult, owing to its complexity and heterogeneity. Integration of supramolecular forces, for example, hydrogen bonds (H-bonds), to anti-cancer ...nanomedicine affords new scaffolds for biomedical material decoration, featuring the advantages of dynamic property and easier processability. Here, we target the construction of H-bond-mediated supramolecular polymer micelles, loaded with a chemotherapeutic drug along with a photothermal agent for synergistic chemo-/photothermal therapies (CT/PTT). To do so, we design and synthesize an amphiphilic ABA-type triblock copolymer, bearing H-bonding moiety (barbiturate, Ba) within the middle hydrophobic B block. The presence of pendant Ba moieties within the hydrophobic core promotes the loading capability of methotrexate (MTX) and transportation stability, benefitting from the formation of specific Ba/MTX H-bonding interactions. IR780, a photothermal agent, concomitantly encapsulated via hydrophobic interactions, facilitates the development of a synergistic CT/PTT modalities, where MTX can be released on demand owing to the dissociation of Ba/MTX H-bonding interactions induced by elevated temperature. Such H-bonding nanomedicine possesses enhanced drug loading capacity and transport performance and can also trigger stimuli-responsive drug release in the tumor zone. We believe that H-bonded nanomedicines provide a fine toolbox that is conducive to attaining biomedical requirements with remarkable values in theranostics that are highly promising in clinical applications.
The outcomes of combined cancer therapy are largely related to loading content and contribution of each therapeutic agent; however, fine-tuning the ratio of two coloaded components toward precise ...cancer therapy is a great challenge and still remains in its infancy. We herein develop a supramolecular polymer scaffold to optimize the coloading ratio of chemotherapeutic agent and photosensitizer through hydrogen-bonding (H-bonding) interaction, for maximizing the efficacy of intelligent cancer chemo/photodynamic therapies (CT/PDT). To do so, we first synthesize a thymine (THY)-functionalized tetraphenylporphyrin photosensitizer (i.e., TTPP), featuring the same molecular configuration of H-bonding array with chemotherapeutic carmofur (e.g., 1-hexylcarbamoyl-5-fluorouracil, HCFU). Meanwhile, a six-arm star-shaped amphiphilic polymer vehicle P(DAPA-co-DPMA-co-OEGMA)6 (poly(diaminopyridine acrylamide-co-2-(diisopropylamino)ethyl methacrylate-co-oligo(ethylene glycol) monomethyl ether methacrylate)6) is prepared, bearing hydrophilic and biocompatible POEGMA segment, along with hydrophobic PDAPA and PDPMA segments, characterizing the randomly dispersed dual functionalities, i.e., heterocomplementary H-bonding DAP motifs and pH-responsive protonation DPMA content. Thanks to the identical DAP/HCFU and DAP/TTPP H-bonding association capability, the incorporation of both HCFU and TTPP to six-arm star-shaped P(DAPA-co-DPMA-co-OEGMA)6 vehicle, with an optimized coloading ratio, can be straightforwardly realized by adjusting the feeding concentrations, thus yielding the hydrogen-bonded supramolecular nanoparticles (i.e., HCFU-TTPP-SPNs), demonstrating the codelivery of two components with the promise to optimize the combined CT/PDT efficacy.
