Reversible CO_(2)-, Photo-and Thermo-Triple Responsive Supramolecular Chirality of Azo-containing Block Copolymer Assemblies Prepared by Polymerization-induced Chiral Self-assembly

Polymerization-induced chiral self-assembly(PICSA)is an efficient strategy that not only allows the construction of the supramolecular chiral assemblies in a controlled manner but also can regulate the morphology in situ.Herein,a series of azobenzene-containing block copolymer(Azo-BCP)assemblies with tunable morphologies and supramolecular chirality were obtained through the PICSA strategy.The supramolecular chirality of Azo-BCP assemblies could be regulated by carbon dioxide(CO_(2))stimulus,and completely recovered by bubbling with Ar.A reversible morphology transformation and chiroptical switching process could also be achieved by the alternative 365 nm UV light irradiation and heatingcooling treatment.Moreover,the supramolecular chirality is thermo-responsive and a reversible chiral-achiral switching was successfully realized,which can be reversibly repeated for at least five times.This work provides a feasible strategy for constructing triple stimuli-responsive supramolecular chiral nano-objects in situ.

Self-assembly synthesis of solid polymer electrolyte with carbonate terminated poly (ethylene glycol) matrix and its application for solid state lithium battery

A facile one-pot synthesis of solid polymer electrolytes(SPEs), composed of carbonate terminated poly(ethylene glycol)(CH3O-PEG-IC), poly(ethylene glycol)-block-polystyrene(PEG-b-PS) block copolymer nanoparticles containing a conductive PEG corona, fumed SiO2 and Li TFSI salt via polymerization-induced self-assembly is proposed. This method to prepare SPEs has the advantages of one-pot convenient synthesis, avoiding use of organic solvent and conveniently adding inorganic additives. CH3O-PEG-IC combines advantages of PEG and polycarbonate, the in situ synthesized PEG-b-PS nanoparticles containing a rigid polystyrene(PS) core and a PEG corona guarantee continuous lithium ion transport in the synthesized SPEs, and the fumed SiO2 optimizes the interfacial properties and improves the electrochemical stability, all of which afford SPEs a well considerable room temperature ionic conductivity of 1.73 × 10^-4S/cm, high lithium transference number of 0.53, and wide electrochemical stability window of 5.5 V(vs. Li^+/Li). By employing these SPEs, the assembled solid state cells of Li FePO4 |SPEs|Li exhibit considerable cell performance.

Engineering Nano/Microscale Chiral Self‑Assembly in 3D Printed Constructs

Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.

Sequence structure controllable polymerization-induced self-assembly

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific components.Herein,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a monomer.During the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat changes.SCPISA-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of assemblies.Moreover,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in SCPISA.The versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

Keto-form directed hierarchical chiral self-assembly of Schiff base derivatives with amplified circularly polarized luminescence

While enol-keto tautomerism has attracted great interest in Schiff bases and related compounds in solution and crystal states,the self-assembly of energy-unfavored keto form were scarcely investigated.Here,we report a keto-form directed self-assembly of a naphthalene-attached enantiomeric N-salicylideneanil analog L/DGG-Nap accompanied with a significantly amplified circularly polarized luminescence(CPL).It was found that LGG-Nap exists as a mixture of enol and keto form in monomer at a diluted toluene solution.The increment of the concentrations leads to the formation of predominated keto form,which subsequently triggers the self-assembly.Cryo-transmission electron microscopy(Cryo-TEM)revealed that a hierarchical assembly process happened upon increasing the concentration of LGG-Nap in toluene.Individual nanofibers formed at 1×10-4 mol/L and transferred into helical nanofiber bundles in 5×10-3 mol/L.Interestingly,while these is nearly no circular dichroism(CD)or CPL in the monomeric solution,the assembly showed strong CD and CPL.Remarkably,the dissymmetry factor(glum)was significantly amplified from zero in solution through the 0.005 in individual nanofiber to 0.1 in nanofiber bundles.This work demonstrates that the enol-keto tautomerism can be broken and trigger the self-assembly upon increasing the concentration,which can subsequently direct the chiral self-assembly and significantly amplify the dissymmetry factor of assembled CPL materials.

Evolution of template-assisted two-dimensional porphyrin chiral grating structure by directed self-assembly using chiral second harmonic generation microscopy

Directed self-assembly has been used to create micro-nano scale patterns,including chiral periodic structures of organic molecules,for potential applications in optics,photonics,metamaterials,and medical and sensing technologies.This study presents a straightforward approach for fabricating large-scale chiral grating porphyrin assemblies through template-assisted techniques.The solution of tetrakis(4-sulfonatophenyl)porphyrin(TPPS)was induced by chiral amino acids(L/D-arginine and L/D-serine)to selfassemble into highly ordered chiral grating structures with the assistance of sodium dodecyl sulfate(SDS).The structures show precise line widths(5.5μm)and gaps(18μm).Using in situ optical microscopy and second harmonic generation(SHG)microscopy,the chiral characteristics and dynamic evolution of the template-assisted self-assembly are investigated.It is found that the chirality of amino acids induced TPPS self-assembled into chiral structures and the liquid contraction interface significantly enhanced the chirality of the assemblies.This study is significant for understanding the mechanism of chiral evolution and designing novel micro-nano materials with predetermined chiral properties.

Chiral liquid crystals based on pillararene and supramolecular self-assembly-induced chirality amplification

Macrocyclic liquid crystals combine the unique property of liquid crystals and excellent supramolecular assembly ability of macrocyclic compounds.It is a significant challenge to make rational use of the advantages of macrocyclic compounds to prepare new macrocyclic mesogens.Pillararenes,a type of macrocycles with rigid pillar-shaped frameworks and easy-tofunctionalize property,are excellent building blocks to fabricate liquid crystal materials.However,the site-selective modification property of pillararene has been rarely exploited to tailor liquid crystal behaviors.Previously reported pillararene-based liquid crystal systems are almost prepared by per-functionalized pillararenes.Herein,we report the regulation of chiral liquid crystal behaviors by different derivatization of pillararene.Lyotropic and thermotropic liquid crystals with different chirality were obtained by self-assembly of pillararene with different numbers of cholesterol groups.The bridge between thermotropic liquid crystal and lyotropic liquid crystal based on pillararene is built.In addition,the chirality of the mesogens can be amplified through supramolecular self-assembly driven by noncovalent interactions.Based on the different liquid crystal behaviors,the optical signal of the pillararene-based chiral liquid crystals was used to fabricate an information encryption system.This work provides a simple strategy to regulate liquid crystal behaviors via pillararene-based mesogens and realizes information encryption through the combination of different types of liquid crystals.

Evolution of hollow nanosphere to microtube in the self-assembly of chiral dansyl derivatives and inversed circularly polarized luminescence

Here,we designed asymmetric(m DS)and symmetrical(d DS)chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2-cyclohexane diamine and investigated the solvent-regulated structural transformation and inversed circularly polarized luminescence(CPL)in the self-assemblies.Upon increasing water volume fraction(fw)in the mixed solvent of water/acetonitrile,asymmetric mDS selfassembled into hollow nanospheres and microtubes,while solid nanospheres and solid microplates were corresponding to symmetric d DS.During this transformation process,the emission of m DS and d DS was changed from yellow-green to blue and cyan color,which was ascribed to twisted intramolecular charge transfer(TICT)and locally excited(LE)fluorescence of V-shaped DS molecules.The conformation of N,Ndimethyl groups with respect to naphthalene ring also led to the transformation of structures.These tubular and platelike structures had stronger and reversed CPL signals in comparison with spheroidal structures.The chiral information of DS assembly could be effective transferred to achiral Nile red via co-assembly strategy,which endowed Nile red exhibiting inversed induced CPL signal regulated by water fraction.This work provides a method for achieving a variety of self-assembled structures with adjustable chiroptical properties.

Enzyme-assisted Photoinitiated Polymerization-induced Self-assembly in Continuous Flow Reactors with Oxygen Tolerance

Polymerization-induced self-assembly(PISA)is an emerging method for the preparation of block copolymer nano-objects at high concentrations.However,most PISA formulations have oxygen inhibition problems and inert atmospheres(e.g.argon,nitrogen)are usually required.Moreover,the large-scale preparation of block copolymer nano-objects at room temperature is challenging.Herein,we report an enzyme-assisted photoinitiated polymerization-induced self-assembly(photo-PISA)in continuous flow reactors with oxygen toleranee.The addition of glucose oxidase(GOx)and glucose into the reaction mixture can consume oxygen efficiently and constantly,allow the flow photo-PISA to be performed under open-air conditions.Polymerization kinetics indicated that only a small amount of GOx(0.5 μmol/L)was needed to achieve the oxygen tolerance.Block copolymer nano-objects with different morphologies can be prepared by varying reaction conditions including the degree of polymerization(DP)of core-forming block,monomer concentration,reaction temperature,and solvent composition.We expect this study will provide a facile platform for the large-scale production of block copolymer nano-objects with different morphologies at room temperature.

Molecular Chirality and Chiral Superlattice in Crystal of Tetrakis[(pyrrol-1-yl)methyl]methane

The crystal structure of tetrakis[(pyrrol-1-yl)methyl]methane was determined by X-ray diffraction measurement, and the result shows that it belongs to monoclinic crystal system, space group is P2 1/n, with a=0.9284(3) nm, b=1.0950(6) nm, c=1.8749(8) nm; α=γ= 90.00(4)°, β=103.63(3)°, V=1.8523(14) nm 3, Z=4, ρ calcd. =1.192 kg/m 3, μ=0.072 nm -1 , F(000)=712, R 1=0.0854, wR 2=0.1884. It has been found that the molecules exist in two enantiomeric states. Enantioselective self-assemblies such as one-dimensional molecular stacks in a single handedness, homochiral monolayers and a chiral superlattice are specified in this racemic crystal. In addition, a simple technique is advocated to distinguish chiral states from tetrahedral molecules in the solid state. The present R/S nomenclature of the tetracooradinated carbon centers is used solely for its convenience to distinguish the two enantiomeric states, but not used to determine the absolute configurations.

Polymerization-Induced Self-Assembly for the Preparation of Poly(N,N-dimethylacrylamide)-b-Poly(4-tert-butoxystyrene-co-pentafluorostyrene)Particles with Inverse Bicontinuous Phases

Main observation and conclusion Polymerization-induced self-assembly(PISA)is an effective method to prepare block copolymer(BCP)particles with various morphologies.However,BCPs with inverse bicontinuous phase structure have been rarely prepared via PISA.Herein,we report the preparation of particles.

Principles and Characteristics of Polymerization-Induced Self-Assembly with Various Polymerization Techniques

A chemical reaction that drives a physical polymer selfassembly process,namely,polymerization-induced self-assembly(PISA),combines block copolymer synthesis and nanoparticle formation efficiently at high polymer concentrations.Various nanoparticlemorphologies such as spheres,worms,and vesicles can be prepared readily in polar and nonpolarmedia.PISA has been well developed in combination with reversible addition-fragmentation chain transfer(RAFT)polymerization.Notably,developments with other polymerization methods are also achieved.In this report,first,we discuss the general principles of RAFT-PISA and the nanoparticles generated from this method.Specifically,new insights into polymer nucleation and subsequent morphological evolution are highlighted.Subsequently,PISA formulations that use other polymerization methods[atom transfer radical polymerization(ATRP),nitroxide-mediated polymerization(NMP),ring-opening metathesis polymerization(ROMP),and ring-opening polymerization(ROP)of N-carboxyanhydrides(NCAs)]are summarized in detail.Finally,more exotic PISA formulations are emphasized:these are based on organotelluriummediated living radical polymerization(TERP),living anionic polymerization(LAP),addition-fragmentation chain transfer(AFCT)polymerization,reversible complexation-mediated polymerization(RCMP),and cobalt-mediated radical polymerization(CMRP),or utilize a comonomer that undergoes radical ringopening polymerization(rROP).This reviewis concluded with a perspective on the status and potential of PISA.

Effect of Butyl α-Hydroxymethyl Acrylate Monomer Structure on the Morphology Produced via Aqueous Emulsion Polymerization-induced Self-assembly

Polymerization-induced self-assembly(PISA) is an efficient and versatile method to afford polymeric nano-objects with polymorphic morphologies. Compared to dispersion PISA syntheses based on soluble monomers, the vast majority of emulsion PISA formulations using insoluble monomers leads to kinetically-trapped spheres. Herein, we present aqueous emulsion PISA formulations generating worms and vesicles besides spheres. Two monomers with different butyl groups, n-butyl(n BHMA) and tert-butyl(t BHMA) α-hydroxymethyl acrylate, and thus possessing different water solubilities were synthesized via Baylis-Hillman reaction. Photoinitiated aqueous emulsion polymerizations of n BHMA and t BHMA employing poly(ethylene glycol) macromolecular chain transfer agents(macro-CTAs, PEG45-CTA, and PEG113-CTA) at 40 °C were systematically investigated to evaluate the effect of monomer structure and solubility on the morphology of the generated block copolymer nano-objects. Higher order morphologies including worms and vesicles were readily accessed for t BHMA, which has a higher water solubility than that of n BHMA. This study proves that plasticization of the core-forming block by water plays a key role in enhancing chain mobility required for morphological transition in emulsion PISA.

Preparation of pH-and reductive-responsive prodrug nanoparticles via polymerization-induced self-assembly

pH-and reductive-responsive prodrug nanoparticles are constructed via a highly efficient strategy, polymerization-induced selfassembly(PISA). First, reversible addition-fragmentation chain transfer(RAFT) polymerization of 2-(diisopropylamino) ethyl methacrylate(DIPEMA) and camptothecin prodrug monomer(CPTM) using biocompatible poly(N-(2-hydroxypropyl) methacrylamide)(PHPMA-CPDB) as the macro RAFT agent is carried out, forming prodrug diblock copolymer PHPMA-P(DIPEMA-co-CPTM). Then, simultaneous fulfillment of polymerization, self-assembly, and drug encapsulation are achieved via RAFT dispersion polymerization of benzyl methacrylate(Bz MA) using the PHPMA-P(DIPEMA-co-CPTM) as the macro RAFT agent. The prodrug nanoparticles have three layers, the biocompatible shell(PHPMA), the drug-conjugated middle layer(P(DIPEMA-co-CPTM)) and the PBz MA core, and relatively high concentration(250 mg/g). The prodrug nanoparticles can respond to two stimuli(reductive and acidic conditions). Due to reductive microenvironment of cytosol, the cleavage of the conjugated camptothecin(CPT) within the prodrug nanoparticles could be effectively triggered. p H-Induced hydrophobic/hydrophilic transition of the PDIPEMA chains results in faster diffusion of GSH into the CPTM units, thus accelerated release of CPT is observed in mild acidic and reductive conditions. Cell viability assays show that the prodrug nanoparticles exhibit well performance of intracellular drug delivery and good anticancer activity.

High-performance nano-splitters containing aggregation-induced emission luminogens for stereoselective crystallization obtained via polymerization-induced self-assembly

Collecting both enantiomorphs with high optical purity and yield in a single crystallization process can be achieved by adding aggregated polymeric“tailor-made”additives,known as nano-splitters.Inefficient preparation and large addition amount have hindered the practical application of such amazing nanoparticles.Herein,we report the first nano-splitters containing aggregation-induced emission luminogens prepared via polymerization-induced self-assembly of block copolymer,poly[(S)-2-(tert-butoxycarbonylamino)-6-(methacrylamido)hexanoic acid]-b-polystyrene,followed by the removal of tert-butoxycarbonyl groups.When added into the supersaturated solution of racemic amino acids(a.a.)with seeds,the fluorescent labeled nano-assemblies enantioselectivity dyed the crystals of S-a.a.and enabled the separation from colorless R-a.a.crystals in terms of fluorescent difference.Both enantiomers were obtained with high optical purity and yield(e.g.,R-asparagine monohydrate,>99 ee%;S-asparagine monohydrate,∼94 ee%;88%total yield).Owing to a low detection limit of fluorescence,the addition amount was reduced to 0.03 wt%without remarkably compromising the ee values of both enantiomorphs.Due to the low addition amount and efficient synthesis,the output–input ratio was increased greatly.

Synchronous Synthesis of Polymeric Vesicles with Controllable Size and Low-Polydispersity by Polymerization-Induced Self-Assembly

Comprehensive Summary The size and size distribution of polymeric nanoparticles have great impact on their physicochemical and biological properties.Polymerization-induced self-assembly(PISA)has been demonstrated to be an efficient method to fabricate various polymeric nanoparticles,among which polymeric vesicles have attracted great interest due to their unique hollow structure.

Advances in self-assembly-based circularly polarized luminescent materials

Circularly polarized luminescent(CPL)materials have garnered attention for their diverse applications,including three-dimensional(3D)imaging,bio-imaging,chiral sensing,and other emerging fields.Traditionally,the fabrication of CPL-activated materials required the use of chiral luminescent small molecules.The introduction of the idea of self-assembly has transformed the production of CPL-activated materials,providing new and promising opportunities for their advancement.Through utilizing self-assembly,it is now feasible to produce chiral nano-assemblies with CPL activity not only from chiral molecules but also from non-chiral substances and inorganic nanoparticles.In addition,self-assembly routes provide a way to increase the asymmetry factor,creating possibilities for additional refinement and adjustment of CPL material characteristics.This review offers a summary of the current progress and developments in the self-assembly of small molecules and polymers,with a specific emphasis on their capacity to create or enhance CPL in different contexts.The aim of this review is to inspire interest in optical materials that are based on the principles of self-assembly.

Ionic Radius Dependent Kinetic Behavior for the Self-Assemblyand Chiral Amplification of Lanthanide Tetrahedral Cages

Comprehensive Summary Understanding the kinetic process during the self-assembly and chiral amplification of metal-organic polyhedra(MOPs)is critical for the rational preparation of chiral MOPs.Herein,we report the ionic radius dependent kinetic processes for the self-assembly and chiral amplification of Ln4L4-type(Ln,Lanthanides;L,ligand)lanthanide tetrahedral cages.The chiral Eu4(LR)4 tetrahedral cage is structurally characterized by nuclear magnetic resonance(NMR),electrospray ionization time-of-flight mass spectrometry(ESI-TOF-MS),and single crystal X-ray diffraction.Kinetic study on the stereo-controlled self-assembly of circularly polarized luminescence(CPL)-active Ln4(LR)4(Ln=LaIII,PrIII and EuIII)tetrahedra manifests that the larger ionic radius of Ln leads to faster assembly rates.Mixed-ligand cage assembly experiments with chiral LR/S,achiral Lac and Ln(1:3:4 molar ratio)reveal that the self-assembly and chiral amplification occur synchronously for the LaIII and PrIII cages,while two distinct steps,i.e.,first self-assembly and then chiral amplification,are observed for the EuIII cage.Such distinct kinetic behavior is attributed to different ligands exchange rates among the mixed-ligand Ln4L4 cages.This work provides fundamental guidance for fabrication and property-optimization of chiral lanthanide-based molecular materials.

Selective formation of luminescent chiral cocrystal:Molecular self-assembly of 2,20-binaphthol and 2-(3-pyridyl)-1H-benzimidazole

Luminescent cocrystals have been received much attention in fluorescence imaging and sensor application. In this work, we report that the high-quality chiral luminescent cocrystal can be obtained through a molecular self-assembly process of 2,20-binaphthol and 2-（3-pyridyl）-1 H-benzimidazole. The assembly modes and stacking fashions of as-obtained cocrystal were determined by single crystal X-ray diffractometer. The structure and optical properties of the cocrystals were characterized by fluorescence emission, fluorescence decay, Raman and circular dichroism spectra. The results show that both the pristine co-assembled units（R-BINOL and S-BINOL） give rise to the R conformation within the final cocrystal, suggesting that the formation of cocrystal can be an effective way to achieve R/S-isomeric transformation of 2,20-binaphthol. It is also expected that the co-crystallization approach has much flexibility and potential applications for the design and selective formation of chiral luminescent materials.

Self-Assembly of Chiral Nano-bowl from Chiral Pd-complex Building Corners and 4,7-Phenanthroline Linkers

A chiral[M_(3)L_(3)]^(6+)-type nanobowl reported here was self-assembled from cis-protected mono-palladium com-plex[(RRdiph)Pd](NO_(3))_(2)(where RRdiph=(1R,2R)-(+)-1,2-diphenylethylenediamine)as chiral corners and 4,7-phenanthroline ligand(L)as linkers in aqueous media.The hydrophobic cavity-containing metallo-macrocycle[Pd_(3)L_(3)]^(6+)·6NO_(3)(1)with a syn,syn,syn orientation has been characterized by 1H NMR spectroscopy,elemental analysis,CD spectra and X-ray diffraction determination.