Supramolecular Hyperbranched Polymer Research Articles

Multistep sequence-controlled supramolecular polymerization by the combination of multiple self-assembly motifs

The precise sequence control of polymer chain is an important research topic of polymer chemistry. Although some methods such as iterative synthesis and supramolecular polymerization have been developed to fabricate sequence-controllable polymer, it is still a great challenge to consecutively prepare multiple supramolecular polymers with different sequence structures. In this work, through the reasonable utilization of assembly motifs, we integrated multiple host-guest recognitions and metal coordination interactions to prepare different sequence-controlled supramolecular polymers by a multistep assembly strategy. This research provides inspiration for the design and preparation of supramolecular polymers with different sequence structures.

An AB2 -Type Hyperbranched Supramolecular Polymer Based on Calix[4]Pyrrole Anion Recognition: Construction, Stimuli-Responsiveness, and Morphology Tuning.

An AB2 -type monomer comprised of a calix[4]pyrrole skeleton and alternating bis-carboxylate units is reported and used for the construction of a novel supramolecular hyperbranched polymer based on anion recognition ability of calix[4]pyrrole. 1 H-, DOSY-NMR spectroscopy, viscosity measurements, and dynamic light scatteringtechniques are used for the characterization of the supramolecular hyperbranched polymer exhibiting thermo-, pH-, and chemical responsiveness, as well as concentration dependent morphology tune as inferred from electron microscopy analyses. The present study enriches the field of supramolecular polymers with a new construction motif, building block, and provides a simple approach for the fabrication of smart polymer material with multi-responsiveness and -morphologies.

A supramolecular hyperbranched polymer constructed by the host–guest interaction and complementary metal-coordination interaction

A supramolecular hyperbranched polymer was constructed based on pillararene-based host–guest recognition and complementary terpyridyl-based metal coordination.

Supramolecular hyperbranched polymer gels based on pillar[5]arene and their applications in removal of micropollutants from water

Two kinds of pillar[5]arene-based supramolecular hyperbranched polymer gels were constructed and applied to efficiently remove micropollutants from water.

Topological-skeleton controlled chirality expression of supramolecular hyperbranched and linear polymers

The topology of polymers plays an essential role in their chemical, physical and biological properties. However, their effects on chirality-related functions remain unclear. Here, we reported the topology-controlled chirality expression in the chiral supramolecular system for the first time. Two topological supramolecular polymers, hyperbranched (HP) and linear (LP) supramolecular polymers produced by the host–guest interactions of branched and linear monomers, respectively, exhibited completely different chirality expressions despite the same molecular chirality of their monomers. Significantly, due to the branch points and strong steric hindrance existing in HP, cis-HP showed an enhanced and sign-inverted Cotton effect in the n–π* bands compared with cis-LP, as a result that the distinctive chirality induction and transfer were controlled by the topological skeletons. This topology-controlled chirality induction and transfer in the photoswitchable supramolecular polymers not only enables us to elucidate the in-depth effects of topology on the chiral expression in biopolymers but also inspires the design of chiroptical and bioinspired materials.

Tunable Multiple Morphological Transformation of Supramolecular Hyperbranched Polymers Based on an A2B6-type POSS Monomer

The growing demands of supramolecular hyperbranched polymers integrating noncovalent interaction and unique topological structure merits had received considerable interests in the fabrication of novel materials for advanced applications. Herein, we prepared A2B6-type POSS-containing supramolecular hyperbranched polymers with multiple morphologies including lamellar-like, branched, hollow, core-shell and porous spherical structures through regulating self-assembling monomer concentrations and solvent polarities. The incorporation of appropriate emulative guest molecules would further trigger morphological transformations (such as vesicles and spherical micelles) by synergistic effects of unique POSS aggregation ability, supramolecular complexations and hydrophilic-hydrophobic interactions. Thus, this facile and universal strategy may enable a modular nanofabrication of supramolecular hyperbranched polymers with diversiform topological structure and sophisticated multifunctionality for their potential applications.

Construction of supramolecular hyperbranched polymers based on a tetrathiafulvalene derivative: Self-assembly and charge transfer interaction with TCNQ

In the present work, a four naphthyl-armed tetrathiafulvalene derivative (TTFB) was designed and synthesized through one-step reaction. Based on the host–guest interaction between naphthyl and cucurbit[8]uril (CB[8]), supramolecular hyperbranched polymers (SHPs) can be constructed in water, depending on hydrogen nuclear magnetic resonance (1H NMR) spectra, UV–vis absorption spectroscopy and diffusion-ordered NMR spectroscopy (DOSY). The self-assembly properties of the SHPs were further investigated by zeta potential analyzer, dynamic laser light scattering (DLS) and transmission electron microscopy (TEM) measurements, which exhibited positively charged spherical structures with the diameter at ~120 nm. More interestingly, the SHPs can interact with TCNQ (7,7,8,8-tetracyanoquinodimethane) to form charge transfer complexes through charge transfer interaction. Meanwhile, the self-assembly structures can be transformed from spherical structures to crosslinked nanoparticles in the charge transfer complexes state.

β-Cyclodextrin modified Pt(II) metallacycle-based supramolecular hyperbranched polymer assemblies for DOX delivery to liver cancer cells

Despite the widespread clinical application of chemotherapeutic anticancer drugs, their adverse side effects and inefficient performances remain ongoing issues. A drug delivery system (DDS) designed for a specific cancer may therefore overcome the drawbacks of single chemotherapeutic drugs and provide precise and synergistical cancer treatment by introducing exclusive stimulus responsiveness and combined chemotherapy properties. Herein, we report the design and synthesis of a supramolecular drug delivery assembly 1 constructed by orthogonal self-assembly technique in aqueous media specifically for application in liver cancer therapy. Complex 1 incorporates the β-cyclodextrin host molecule-functionalized organoplatinum(II) metallacycle 2 with two specific stimulus-responsive motifs to the signaling molecule nitric oxide (NO), in addition to the three-armed polyethylene glycol (PEG) functionalized ferrocene 3 with redox responsiveness. With this molecular design, the particularly low critical aggregation concentration (CAC) of assembly 1 allowed encapsulation of the commercial anticancer drug doxorubicin (DOX). Controlled drug release was also achieved by morphological transfer via a sensitive response to the endogenous redox and NO stimuli, which are specifically related to the microenvironment of liver tumor cells. Upon combination of these properties with the anticancer ability from the platinum acceptor, in vitro studies demonstrated that DOX-loaded 1 is able to codeliver anticancer drugs and exhibit therapeutic effectiveness to liver tumor sites via a synergistic effect, thereby revealing a potential DDS platform for precise liver cancer therapeutics.

Quadruple hydrogen bonded hyperbranched supramolecular polymers with aggregation-induced emission for artificial light-harvesting

In the present work, a tetraphenylethylene (TPE) derivative with four ureidopyrimidinones (TPE-tetraUPy) was synthesized through a two-step reaction, which could make up supramolecular hyperbranched polymers in CHCl3 through quadruple hydrogen bonding interactions with aggregation-induced emission (AIE). The supramolecular hyperbranched polymers were characterized by Fourier transformed infrared (FT-IR), viscosity measurement, 1H NMR spectra, and steady-state spectra. The as-prepared supramolecular hyperbranched polymers can further self-assemble to form nanoparticles in CHCl3/hexane mixture (1:99, v/v) or form nanoparticles in uniform shape and size using the miniemulsion method with cetyltrimethyl ammonium bromide (CTAB) as a surfactant. From the supramolecular nanoparticles prepared in the miniemulsion method, we construct a light-harvesting system to study the excitation energy transfer properties by using the electrostatic assembly of negatively charged sulforhodamine 101 (SR101) on the nanoparticles, which exhibited a high energy transfer efficiency (37.2%) and antenna effect (30.7).

Construction of β-cyclodextrin-based supramolecular hyperbranched polymers self-assemblies using AB2-type macromonomer and their application in the drug delivery field

Despite some efforts have been made in the research of supramolecular hyperbranched polymers (SHPs) self-assemblies, the study which has not been consideration to date is the influence of incoming stimuli-responsive polymer chain on their self-assembly property undergo outer stimuli. The introduction of stimuli-responsive segments which could maintain their hydrophilic property are expected to affect the self-assembly behaviour of SHPs and expand their further biomedical application. In this paper, AB2-type macromolecular monomer, LA-(CD-PDMA)2, which consisted one lithocholic acid (LA) and two β-cyclodextrin terminated poly(2-(dimethylamino)ethyl methacrylate) segments (CD-PDMA) was synthesized. LA-(CD-PDMA)2 based SHP were obtained based on the host-guest inclusion interactions of CD/LA moietes and with PDMA as pH-responsive hydrophilic chains. As a control to study the influence of incoming PDMA chains, both LA-(CD-PDMA)2 based SHPs-1 and LA-CD2 based SHPs-2 self-assemblies were comparatively investiged through 2D 1H NMR ROESY, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results suggested that except for the higher drug loading efficiency LA-(CD-PDMA)2 based SHPs-1 pocessing, the release rates of SHPs-1 increased notably at pH 5.0 than that of pH 7.4 due to the repulsion and stretch of protonated PDMA chains while the release rates of SHPs-2 showed no obvious difference. Finally, basic cell experiments demonstrated that the SHPs based self-assemblies can be internalized into cancer cells, indicating their potential application in the drug delivery field.

A photo-switchable supramolecular hyperbranched polymer with aggregation-induced emission based on host-guest interaction

In this work, we report a simple strategy by mixing a coumarin appended tetraphenylethylene derivative (TPEC) and γ-cydodextrin(γ-CD) in aqueous solution, based on the host-guest interaction between TPEC and γ-CD to construct a dual-modality supramolecular hyperbranched polymer. The host-guest interaction between γ-CD and TPEC efficiently restricted the intramolecular rotation and the non-radiative relaxation channel, minimizing energy loss, thereby resulting in the strong emission of TPEC in dilute solution. Moreover, we achieved the conversion between non-covalent supramolecular hyperbranched polymers and its corresponding covalent supramolecular hyperbranched polymers under the irradiation of UV light, which can be reversibly controlled through the irradiation at the wavelengths of 254 nm and 365 nm. Furthermore, both non-covalent supramolecular hyperbranched polymers and covalent supramolecular hyperbranched polymers can self-assemble into spherical structures. This methodology provides a new idea for exploring a new type of supramolecular hyperbranched polymers with aggregation-induced emission.

A Mechanically Robust, Stiff, and Tough Hyperbranched Supramolecular Polymer Hydrogel.

In this study, a simple yet versatile method is introduced to prepare a hyperbranched supramolecular polymer hydrogel by utilizing Type II photoinitiated self-condensing vinyl polymerization of N-acryloyl glycinamide, which can serve not only as an inimer providing branching sites, but also as a hydrogen-bonding cross-linker. The hyperbranched poly(N-acryloyl glycinamide) (HB-PNAGA) hydrogels demonstrate excellent mechanical performances with a tensile strength of 0.793-2.724MPa, elongation at break of 203-902%, Young's modulus of 0.450-1.172MPa, and maximal fracture energy of 2200 J m-2 , which are all superior to those of linear PNAGA hydrogels. The results indicate that the HB-PNAGA hydrogel is very stiff and tough due to much higher H-bonding cross-linking density formed in hyperbranched architecture. The high stiffness, toughness, and ease of preparation make these hyperbranched supramolecular hydrogels very attractive for application as soft supporting tissue replacements.

Size‐Stable Supramolecular Hyperbranched Polymer Vesicles for Redox‐Triggered Double‐Drug Release

AbstractSupramolecular polymer vesicles (SPVs) with stimuli‐responsive features are promising multifunctional nanocarriers; however, improving the stability and developing multiple‐drug‐loaded SPVs remain key issues in this field. In this work, cross‐linked supramolecular hyperbranched polymer vesicles (SHPVs) with redox‐responsiveness are first constructed based on an AB2‐type macromonomer‐synthesized SHP. The obtained cross‐linked SHPVs exhibit much better size stability than those of non‐cross‐linked branched self‐assemblies, and higher double‐drug‐loading capacity compared with linear supramolecular polymer self‐assemblies. Particularly, these cross‐linked SHPVs exhibit a redox‐triggered, controlled double‐drug release behavior upon the addition of H2O2.

An AB2‐Type Supramolecular Hyperbranched Polymer Based on Pillar[5]arene Host–Guest Recognition: Construction and Its pH‐Responsiveness

Supramolecular hyperbranched polymers not only possess the polymeric properties of hyperbranched polymers but also obtain additional stimuli-responsiveness due to the dynamic properties of non-covalent interactions. Herein, a novel supramolecular hyperbranched polymer constructed by an AB2 -type copillar[5]arene is reported. NMR spectroscopy, scanning electron microscopy, and viscosity experiments are utilized to characterize the self-aggregate process of the AB2 monomers. Interestingly, the supramolecular hyperbranched polymer exhibits pH-responsiveness. After protonation of the AB2 monomers by trifluoroacetic acid, the binding ability among the monomers becomes stronger, leading to the formation of supramolecular hyperbranched polymers with viscosity change. Additionally, although no conventional chromophores are doped, the supramolecular hyperbranched polymer shows a blue emission under irradiation. The fluorescence can be quenched upon addition of trifluoroacetic acid. This study enriches the field of supramolecular polymers with new building blocks and architectures and provided a new effective method for the fabrication of smart polymer materials with stimuli-responsiveness and special functions.

A Color-Tunable Fluorescent Supramolecular Hyperbranched Polymer Constructed by Pillar[5]arene-Based Host-Guest Recognition and Metal Ion Coordination Interaction.

Fluorescent supramolecular polymers are an important kind of smart material. In this work, a new fluorescent supramolecular hyperbranched polymer (FSHP) is constructed by orthogonal self-assembly: pillararene-based host-guest interaction and metal ion complexation interaction. The FSHP exhibits concentration-controllable fluorescence emissions. The photoluminescence spectra and light-emitting colors of FSHP can be effectively tuned by changing metal ion types or using mixed metal ions. The fluorescence quenching of FSHP solutions or FSHP-based films would occur when removing the metal ions from the backbone of FSHP. This study supplies a convenient approach toward the construction of structure-tunable fluorescent supramolecular materials with different colors.

A supramolecular hyperbranched polymer with multi-responsiveness constructed by pillar[5]arene-based host–guest recognition and its application in the breath figure method

A supramolecular gel with multi-responsiveness or honeycomb-patterned film was constructed by pillararene-based host–guest recognition.

A dual-responsive hyperbranched supramolecular polymer constructed by cooperative host-guest recognition and hydrogen-bond interactions.

A homotritopic pillar[5]arene (H3) containing adenine units was synthesized and employed to interact with a uracil derivative (6-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)hexanenitrile, G) to form a hyperbranched supramolecular polymer. The hyperbranched supramolecular polymer showed a dual stimulus response both to heat and acid/base. The cooperative host-guest binding and hydrogen-bond interactions play a key role in the supramolecular polymerization.

Fabrication of POSS-embedded supramolecular hyperbranched polymers with multi-responsive morphology transitions

We demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers with multiple stimulus morphology transitions driven by triple supramolecular driving forces in selective solvents.

POSS-embedded supramolecular hyperbranched polymers constructed from a 1→7 branching monomer with controllable morphology transitions

The research on the supramolecular hyperbranched polymers (SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers (POSS-SHPs) with varied morphology and size by controlling monomer concentration and mixed solvents. The SHPs formations can further transfer into the core-shell structured micelles by addition of competitive guests based on the double supramolecular driving forces.

Supramolecular hyperbranched polymers with aggregation-induced emission based on host-enhanced π–π interaction for use as aqueous light-harvesting systems

In this work, we report a simple strategy by mixing a naphthyl-substituted tetraphenylethylene derivative (TPE) and cucurbit[8]uril (CB[8]) in aqueous solution, based on the host-guest complexation between CB[8] and TPE, to construct supramolecular hyperbranched polymers. The host-guest interaction between CB[8] and TPE efficiently restricted the intramolecular rotation and the non-radiative relaxation channel, thereby resulting in the strong emission of TPE in dilute solution. We further investigate the self-assembly behaviors of the obtained supramolecular hyperbranched polymers in aqueous solution, which exhibited individual spherical aggregates with the diameter of ∼60 nm. By using the spherical aggregates as energy donors and eosin Y disodium salt (EY) as energy acceptors, we have constructed highly efficient aqueous light-harvesting systems in aqueous solution.