Block Copolymer Molecules Research Articles

Assembly of P2VP and PS-b-P2VP composite helical nanowire arrays at the liquid/liquid interface

The nanostructures based on polymers have attracted much research interest because of their rich morphologies, unique properties and potential applications in various fields. In particular, helical nanostructures have been research hotspots in recent years. In this work, composite non-helical and helical nanowire arrays of atactic poly(2-vinylpyridine) (P2VP), and block copolymers polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) were fabricated successfully with inorganic species such as HAuCl4 through a liquid/liquid interfacial adsorption and self-assembly approach without addition of any chiral inducers. The formation process of the helical nanowires of P2VP includes the following steps, i.e. adsorption of the polymer molecules and HAuCl4 at the interface, the following protonation of pyridine groups, straightening of the P2VP chains by mutual repulsion between the protonated pyridine groups, aggregation of the P2VP chains due to the hydrophobic interactions between the backbones, and ordered organization of the pyridine groups through π-π interactions. The helical nanowires of PS-b-P2VP are worm-like micelles with a PS core and a P2VP shell, which are formed through the self-assembly of the block copolymer molecules with HAuCl4 within the interfacial phase with the help of hydrophobic interaction between the PS blocks and orderly stacking of the P2VP blocks. The different formation mechanisms reflected the effects of molecular structure on the self-assembly of polymers. In addition, the formed nanowires further self-organize into ordered arrays due to the increasing interfacial pressure during the generation of the nanowires. The results of this study expand the scope of research on polymer self-assembly and the application of liquid/liquid interfacial self-assembly techniques to acquire highly ordered supramolecular nanostructures.

Polymer-Tethered Nanoparticles: From Surface Engineering to Directional Self-Assembly.

Current interest in nanoparticle ensembles is motivated by their collective synergetic properties that are distinct from or better than those of individual nanoparticles and their bulk counterparts. These new advanced optical, electronic, magnetic, and catalytic properties can find applications in advanced nanomaterials and functional devices, if control is achieved over nanoparticle organization. Self-assembly offers a cost-efficient approach to produce ensembles of nanoparticles with well-defined and predictable structures. Nanoparticles functionalized with polymer molecules are promising building blocks for self-assembled nanostructures, due to the comparable dimensions of macromolecules and nanoparticles, the ability to synthesize polymers with various compositions, degrees of polymerization, and structures, and the ability of polymers to self-assemble in their own right. Moreover, polymer ligands can endow additional functionalities to nanoparticle assemblies, thus broadening the range of their applications.In this Account, we describe recent progress of our research groups in the development of new strategies for the self-assembly of nanoparticles tethered to macromolecules. At the beginning of our journey, we developed a new approach to patchy nanoparticles and their self-assembly. In a thermodynamically driven strategy, we used poor solvency conditions to induce homopolymer surface segregation in pinned micelles (patches). Patchy nanoparticles underwent self-assembly in a well-defined and controlled manner. Following this work, we overcame the limitation of low yield of the generation of patchy nanoparticles, by using block copolymer ligands. For block copolymer-capped nanoparticles, patch formation and self-assembly were "staged" by using distinct stimuli for each process. We expanded this work to the generation of patchy nanoparticles via dynamic exchange of block copolymer molecules between the nanoparticle surface and micelles in the solution. The scope of our work was further extended to a series of strategies that utilized the change in the configuration of block copolymer ligands during nanoparticle interactions. To this end, we explored the amphiphilicity of block copolymer-tethered nanoparticles and complementary interactions between reactive block copolymer ligands. Both approaches enabled exquisite control over directional and self-limiting self-assembly of complex hierarchical nanostructures. Next, we focused on the self-assembly of chiral nanostructures. To enable this goal, we attached chiral molecules to the surface of nanoparticles and organized these hybrid building blocks in ensembles with excellent chiroptical properties. In summary, our work enables surface engineering of polymer-capped nanoparticles and their controllable and predictable self-assembly. Future research in the field of nanoparticle self-assembly will include the development of effective characterization techniques, the synthesis of new functional polymers, and the development of environmentally responsive self-assembly of polymer-capped nanoparticles for the fabrication of nanomaterials with tailored functionalities.

Increased Protein Encapsulation in Polymersomes with Hydrophobic Membrane Anchoring Peptides in a Scalable Process.

Hollow vesicles made from a single or double layer of block-copolymer molecules, called polymersomes, represent an important technological platform for new developments in nano-medicine and nano-biotechnology. A central aspect in creating functional polymersomes is their combination with proteins, especially through encapsulation in the inner cavity of the vesicles. When producing polymersomes by techniques such as film rehydration, significant proportions of the proteins used are trapped in the vesicle lumen, resulting in high encapsulation efficiencies. However, because of the difficulty of scaling up, such methods are limited to laboratory experiments and are not suitable for industrial scale production. Recently, we developed a scalable polymersome production process in stirred-tank reactors, but the statistical encapsulation of proteins resulted in fairly low encapsulation efficiencies of around 0.5%. To increase encapsulation in this process, proteins were genetically fused with hydrophobic membrane anchoring peptides. This resulted in encapsulation efficiencies of up to 25.68%. Since proteins are deposited on the outside and inside of the polymer membrane in this process, two methods for the targeted removal of protein domains by proteolysis with tobacco etch virus protease and intein splicing were evaluated. This study demonstrates the proof-of-principle for production of protein-functionalized polymersomes in a scalable process.

NMR Study of the Dissolution of Core-Crystalline Micelles

Short fragments of the core-crystalline micelles formed by a sample of poly(ferrocenyldimethylsilane)-block-poly(isoprene) (PFS-b-PI) block copolymer (BCP) underwent self-seeding in decane when heated above its dissolution temperature. Variable temperature (VT) 1H NMR and diffusion-ordered pulsed-gradient spin–echo (DOSY) NMR were used to monitor the behavior of micelles that dissolved as a function of increasing temperature. We examined a sample of micelle fragments of PFS65-b-PI637 characterized by Ln = 39 nm and Lw/Ln = 1.13. The PI corona had high mobility and gave a 1H NMR signal in both micellar and unimer forms. In contrast, the PFS component could only be detected for the dissolved unimer. We found from 1H NMR that essentially all the BCP molecules were incorporated into the micelles at temperatures up to and including 50 °C, at the limit of NMR detection. Both PFS and PI resonances could be detected between 70 and 100 °C, and the integration ratio of the PFS-to-PI peaks increased with temperature...

Antifouling Properties of a Self-Assembling Glutamic Acid-Lysine Zwitterionic Polymer Surface Coating.

There is a need for the development of antifouling materials to resist adsorption of biomacromolecules. Here we describe the preparation of a novel zwitterionic block copolymer with the potential to prevent or delay the formation of microbial biofilms. The block copolymer comprised a zwitterionic (hydrophilic) section of alternating glutamic acid (negatively charged) and lysine (positively charged) units and a hydrophobic polystyrene section. Cryo-TEM and dynamic-light-scattering (DLS) results showed that, on average, the block copolymer self-assembled into 7-nm-diameter micelles in aqueous solutions (0 to 100 mM NaCl, pH 6). Quartz crystal microbalance with dissipation monitoring (QCM-D), atomic force microscopy (AFM), and contact angle measurements demonstrated that the block copolymer self-assembled into a brush-like monolayer on polystyrene surfaces. The brush-like monolayer produced from a 100 mg/L block copolymer solution exhibited an average distance, d, of approximately 4-8 nm between each block copolymer molecule (center to center). Once the brush-like monolayer self-assembled, it reduced EPS adsorption onto the polystyrene surface by ∼70% (mass), reduced the rate of bacterial attachment by >80%, and inhibited the development of thick biofilms. QCM-D results revealed that the EPS molecules penetrate between the chains of the brush and adsorb onto the polystyrene surface. Additionally, AFM analyses showed that the brush-like monolayer prevents the adhesion of large (> d) hydrophilic colloids onto the surface via hydration repulsion; however, molecules or colloids small enough to fit between the brush polymers (< d) were able to be adsorbed onto the surface via van der Waals interactions. Overall, we found that the penetration of extracellular organelles, as well as biopolymers through the brush, is critical for the failure of the antifouling coating, and likely could be prevented through tuning of the brush density. Stability and biofilm development testing on multiple surfaces (polypropylene, glass, and stainless steel) support practical applications of this novel block copolymer.

Fundamental properties, self-assembling behavior, and their temperature and salt responsivity of ionic amphiphilic diblock copolymer having poly(N-isopropylacrylamide) in aqueous solution

Molecular properties and self-assembling behavior of thermo-responsive ionic diblock copolymers, poly(N-isopropylacrylamide)-b-poly(styrenesulfonate sodium salt) (PNIPAm-b-PSSNa), which were precisely synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, were systematically studied as a function of temperature and added salt concentrations. Cloud point with elevation aqueous solution temperature was found at 35~40 °C for all the block copolymers studied which have a different block length and block ratio. Cloud point decreased with increasing added salt concentration, which was identified to be the critical micelle temperature (CMT) since micelle formation was confirmed at a higher temperature. The critical micelle concentration (cmc) at 50 °C could be determined by the static light scattering technique and cmc was found to increase with increasing added salt concentration. This is behavior typical of “non-surface active” polymers although it does not obey the famous Corin-Harkins law for ionic surfactants. However, the surface tension of the solution decreased with increasing polymer concentration and the adsorption of block copolymer molecules at the water surface was directly confirmed by X-ray reflectivity and foam formation observation. Micelle size was found to increase with increasing polymer concentration by dynamic light scattering. Vesicle-like particles were found by transmission electron microscopy (TEM) observation for some block copolymers. PNIPAm-b-PSSNa behaves as an amphiphilic block copolymer at 50 °C and has a non-surface active nature since it has an ionic block. However, the discrepancy between the non-surface active nature of cmc behavior and surface active nature of adsorption is quite mysterious, and this might be peculiar to PNIPAm-containing block copolymers since similar behavior was not observed in other ionic amphiphilic block copolymers having a conventional hydrophobic block.

Enhanced Charge Carrier Mobility and Tailored Luminescence of n‐Type Organic Semiconductor through Block Copolymer Supramolecular Assembly

Herein, a novel and viable strategy to fabricate fully solution processable nanostructured n‐type organic semiconducting material through block copolymer supramolecular assembly consisting of polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) and an asymmetric perylenebisimide (PBI) has been demonstrated. The block copolymer supramolecular assemblies show hierarchical structure formation in two length scales (lamella within lamella) from synergistic phase separation of block copolymer and PBI molecule inside the comb block. The optical and luminescent studies clearly evidence that the nature of aggregation of the PBI molecules inside the P4VP domain through facial π–π stacking is modified with tailored luminescent properties compared to its pure state. The block copolymer supramolecular assembly with 1:1 mole ratio (4‐vinyl pyridine:PBI) shows almost three‐order enhancement of charge carrier mobility compared to pristine PBI though it has only (0.571) of PBI weight fraction. It is believed that the organic semiconductor polymeric system described here will be useful for preparing luminescent materials, organic electronic and optoelectronic devices. image

Impact of dispersed particles on the structure and shear alignment of block copolymer soft solids

At high concentrations, solvent-selective block copolymer molecules self-assemble into concentrated micellar solutions that form highly ordered, nanostructured, soft solids. Solvent stable nanoparticles dispersed in these soft solids will sample the solvent-swollen, continuous structure, providing a method to template, store, and define the environment of nanoparticulate material. Globular proteins are used as nanoparticulate material and dispersed into two different block copolymer solutions (Pluronic® P123 and P103) that differ slightly in block length but not chemistry or architecture. We characterize the impact of added nanoparticles on the local micelle packing, flow mechanism, and overall structure of the soft solid. Small angle neutron scattering with contrast variation and rheology are used to characterize the structure and mechanical behavior of the system. In the P123 soft solid, added nanoparticles change the local order of the cubic and cylindrical phases. In the P103 soft solid, added nanopar...

Hierarchical composite microstructures fabricated at the air/liquid interface through multilevel self-assembly of block copolymers

Hierarchical composite microstructures of block copolymers, polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP)/Ag have been fabricated successfully at the air/liquid interface through a self-assembly and adsorption process. The films with various morphologies including foam, nanorod and nanowire array, hollow sphere, and nanosphere were obtained. These morphologies are closely related to the aggregates formed in the aqueous phase, such as microcapsules, cylindrical micelles, vesicles and spherical micelles, which can be controlled by tuning the critical packing parameters of the amphiphilic block copolymer molecules through changing the concentration of Ag+ ions in the aqueous solution. The length of the P2VP blocks in the PS-b-P2VPs exerts great influences on the self-assembly behavior of the polymers and the final microstructures, which provides a deep insight into the formation mechanism of the microstructures. Additionally, these hybrid films doped with silver nanoparticles provide potential application in surface enhanced Raman scattering (SERS) and catalysis.

Carboplatin-Complexed and cRGD-Conjugated Unimolecular Nanoparticles for Targeted Ovarian Cancer Therapy.

Platinum-based chemotherapy has been widely used to treat cancers including ovarian cancer; however, it suffers from dose-limiting toxicity. Judiciously designed drug nanocarriers can enhance the anticancer efficacy of platinum-based chemotherapy while reducing its systemic toxicity. Herein the authors report a stable and water-soluble unimolecular nanoparticle constructed from a hydrophilic multi-arm star block copolymer poly(amidoamine)-b-poly(aspartic acid)-b-poly(ethylene glycol) (PAMAM-PAsp-PEG) conjugated with both cRGD (cyclo(Arg-Gly-Asp-D-Phe-Cys) peptide and cyanine5 (Cy5) fluorescent dye as a platinum-based drug nanocarrier for targeted ovarian cancer therapy. Carboplatin is complexed to the poly(aspartic acid) inner shell via pH-responsive ion-dipole interactions between carboplatin and the carboxylate groups of poly(aspartic acid). Based on flow cytometry and confocal laser scanning microscopy analyses, cRGD-conjugated unimolecular nanoparticles exhibit much higher cellular uptake by ovarian cancer cells overexpressing αv β3 integrin than nontargeted (i.e., cRGD-lacking) ones. Carboplatin-complexed cRGD-conjugated nanoparticles also exhibit higher cytotoxicity than nontargeted nanoparticles as well as free carboplatin, while empty unimolecular nanoparticles show no cytotoxicity. These results indicate that stable unimolecular nanoparticles made of individual hydrophilic multi-arm star block copolymer molecules conjugate with tumor-targeting ligands and dyes (i.e., PAMAM-PAsp-PEG-cRGD/Cy5) are promising nanocarriers for platinum-based anticancer drugs for targeted cancer therapy.

Fabrication of polymersomes with controllable morphologies through dewetting w/o/w double emulsion droplets

In this work, monodisperse giant polymersomes are fabricated by dewetting of water-in-oil-in-water double emulsion droplets which are assembled by amphiphilic block copolymer molecules in a microfluidic device. The dewetting process can be tuned by solvation between solvent and amphiphilic block copolymer to get polymersomes with controllable morphology. Good solvent (chloroform and toluene) hinders dewetting process of double emulsion droplets and gets acornlike polymersomes or patched polymersomes. On the other hand, poor solvent (hexane) accelerates the dewetting process and achieves complete separation of inner water phase from oil phase to form complete bilayer polymersomes. In addition, twin polymersomes with bilayer membrane structure are formed by this facile method. The formation mechanism for different polymersomes is discussed in detail.

Morphological evolution of block copolymer nanocomposites submitted to extensional flows

In this work, the effect of extensional flow on the morphology of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymers and their clay-containing nanocomposites was evaluated. Four types of SEBS copolymers with different block compositions and cylindrical morphology were chosen to understand the effects of cylinder orientation and state of clay dispersion on the evolution of morphology during extensional flow. The effect of clay concentration (ranging from 2.5 to 7.5 wt. %) was also studied. The samples were subjected to extensional flow using a Sentmanat extensional rheometer attached to a rotational rheometer at Hencky strain rates varying from 0.01 to 20 s−1. Small angle X-ray scattering analysis was subsequently performed to evaluate the morphological changes caused by extensional flow. When preoriented block copolymers [SEBS-30% PS (polystyrene)] and their nanocomposites undergo elongation, the styrene cylinders and clay nanoparticles align themselves in the flow direction and their rheological behavior and morphological evolution are influenced by the stretching direction (longitudinal and transverse), strain rate magnitude, clay concentration, and dispersion state of the clay nanoparticles. When isotropic block copolymers (SEBS-13% PS) undergo elongation, it was observed that the PS cylinders only exhibit structural alignment in the stretching direction in the presence of clay. Block copolymer molecules can exhibit different relaxation times depending upon the volume fraction of PS domains (13% or 30%). The addition of clay, however, hinders complete relaxation, helping to promote a permanent domain alignment after flow cessation, especially in hard-to-align copolymers.

Mixed Hybrid Lipid/Polymer Vesicles as a Novel Membrane Platform.

Vesicles can be individually fabricated from naturally occurring lipid or synthetic block copolymer molecules via self-assembly in aqueous solutions; the blending of both vesicle-forming amphiphiles leads to the formation of hybrid membranes. Their final stabilities and lateral morphologies are strongly determined by the molar composition, size, and charge properties of the interacting components as well as by the lipid chain melting temperature. Upon merging the best properties of lipo- and polymersomal membranes, hybrid lipid/polymer vesicles represent a new scaffold for medical applications combining, e.g., combining the biocompatibility of liposomes with the high thermal and mechanical stability and functional variability of polymersomes within a single vesicle type. Up to now, several hybrid membrane systems and their corresponding vesicular morphologies have been studied, highlighting the attractive properties and features useful in selective delivery receptor scaffolding.

Ultrathin random copolymer-grafted layers for block copolymer self-assembly.

Hydroxyl-terminated P(S-r-MMA) random copolymers (RCPs) with molecular weights (Mn) from 1700 to 69000 and a styrene unit fraction of approximately 61% were grafted onto a silicon oxide surface and subsequently used to study the orientation of nanodomains with respect to the substrate, in cylinder-forming PS-b-PMMA block copolymer (BCP) thin films. When the thickness (H) of the grafted layer is greater than 5-6 nm, a perpendicular orientation is always observed because of the efficient decoupling of the BCP film from the polar SiO2 surface. Conversely, if H is less than 5 nm, the critical thickness of the grafted layer, which allows the neutralization of the substrate and promotion of the perpendicular orientation of the nanodomains in the BCP film, is found to depend on the Mn of the RCP. In particular, when Mn = 1700, a 2.0 nm thick grafted layer is sufficient to promote the perpendicular orientation of the PMMA cylinders in the PS-b-PMMA BCP film. A proximity shielding mechanism of the BCP molecules from the polar substrate surface, driven by chain stretching of the grafted RCP molecules, is proposed.

A new strategy to fabricate composite thin films with tunable micro- and nanostructures via self-assembly of block copolymers.

A new and facile strategy to fabricate composite thin films with tunable morphologies via self-assembly of block copolymer molecules at the air/liquid interface is first reported. The morphologies (parallel nanowires and foams) of these freestanding thin films can be tuned by varying the molecular structure or other experimental conditions.

“Non-equilibrium” block copolymer micelles with glassy cores: A predictive approach based on theory of equilibrium micelles

Micelles generated in water from most amphiphilic block copolymers are widely recognized to be non-equilibrium structures. Typically, the micelles are prepared by a kinetic process, first allowing molecular scale dissolution of the block copolymer in a common solvent that likes both the blocks and then gradually replacing the common solvent by water to promote the hydrophobic blocks to aggregate and create the micelles. The non-equilibrium nature of the micelle originates from the fact that dynamic exchange between the block copolymer molecules in the micelle and the singly dispersed block copolymer molecules in water is suppressed, because of the glassy nature of the core forming polymer block and/or its very large hydrophobicity. Although most amphiphilic block copolymers generate such non-equilibrium micelles, no theoretical approach to a priori predict the micelle characteristics currently exists. In this work, we propose a predictive approach for non-equilibrium micelles with glassy cores by applying the equilibrium theory of micelles in two steps. In the first, we calculate the properties of micelles formed in the mixed solvent while true equilibrium prevails, until the micelle core becomes glassy. In the second step, we freeze the micelle aggregation number at this glassy state and calculate the corona dimension from the equilibrium theory of micelles. The condition when the micelle core becomes glassy is independently determined from a statistical thermodynamic treatment of diluent effect on polymer glass transition temperature. The predictions based on this “non-equilibrium” model compare reasonably well with experimental data for polystyrene–polyethylene oxide diblock copolymer, which is the most extensively studied system in the literature. In contrast, the application of the equilibrium model to describe such a system significantly overpredicts the micelle core and corona dimensions and the aggregation number. The non-equilibrium model suggests ways to obtain different micelle sizes for the same block copolymer, by the choices we can make of the common solvent and the mode of solvent substitution.

Advanced micromachining of concave microwells for long term on-chip culture of multicellular tumor spheroids.

A novel approach based on advanced micromachining is demonstrated to fabricate concave microwell arrays for the formation of high quality multicellular tumor spheroids. Microfabricated molds were prepared using a state-of-the-art CNC machining center, containing arrays of 3D convex micropillars with size ranging from 150 μm to 600 μm. Microscopic imaging of the micropillars machined on the mold showed smooth, curved microfeatures of a dramatic 3D shape. Agarose microwells could be easily replicated from the metallic molds. EMT-6 tumor cells seeded in the primary macrowell sedimented efficiently to the bottom of the concave microwells and formed multicellular spheroids within 48 h. Dense and homogeneous multicellular spheroids were obtained after 10 days of culture, confirming the suitability of the proposed approach. To facilitate long term spheroid culture and reliable on-chip drug assay, polydimethylsiloxane microwells were also replicated from the metallic molds. A solvent swelling method was adapted and optimized to Pluronic F127 towards physically entrapping the block copolymer molecules within the polydimethylsiloxane network and in turn to improve long term cell-binding resistance. Homogeneous multicellular spheroids were efficiently formed in the concave microwells and on-chip drug assays could be reliably carried out using curcumin as a model anti-cancer drug. Advanced micromachining provides an excellent technological solution to the fabrication of high quality concave microwells.

Thermoregulated Formation and Disintegration of Cationic Block Copolymer Vesicles: Fluorescence Resonance Energy Transfer Study

Formation and disintegration of self-assembled nanostructures in response to external stimuli are important phenomena that have been widely explored for a variety of biomedical applications. In this contribution, we report the thermally triggered assembly of block copolymer molecules in aqueous solution to form vesicles (polymersomes) and their disassembly on reduction of temperature. A new thermoresponsive diblock copolymer of poly(N-isopropylacrylamide) poly((3-methacrylamidopropyl)trimethylammonium chloride) (PNIPA-b-PMAPTAC) was synthesized by reversible addition-fragmentation chain transfer technique. The solution properties and self-assembling behavior of the block copolymer molecules were studied by turbidimetry, temperature-dependent proton nuclear magnetic resonance, fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. Fluorescence resonance energy transfer studies between coumarin-153 (C-153, donor) and rhodamine 6G (R6G, acceptor) have been performed by steady-state and picosecond-resolved fluorescence spectroscopy to probe the structural and dynamic heterogeneity of the vesicles. The occurrence of efficient energy transfer was evident from the shortening of donor lifetime in the presence of the acceptor. The capability of the vesicles to encapsulate both hydrophobic and hydrophilic molecules and release them in response to decrease in temperature makes them potentially useful as drug delivery vehicles.

A novel method for hydrogel nanostructuring

Nanostructured hydrogels tailor-made for specific applications are new grounds for the creation of novel soft materials. The current research presents a new method for hydrogel nanostructuring involving the incorporation of Pluronic® F127 micelles mixed with acrylated blockcopolymer molecules, which enable the attachment of these micelles to the hydrogel matrix through their endgroups. This design impacts the hydrogel nanostructure as well as its swelling and mechanical properties. Small Angle X-ray Scattering (SAXS) and Cryogenic Transmission Electron Microscopy (cryo-TEM) revealed that photochemical crosslinking of the hydrogel caused immobilization of the nanostructured micelles. Mechanical and weight gain experiments demonstrated a significant impact of these nanostructures on the hydrogel’s elastic modulus as well as the transient and equilibrium weight gain ability of the material.

Honeycomb-like thin films of Polystyrene-block-poly(2-vinylpyridine) embedded with gold or silver nanoparticles formed at the planer liquid/liquid interface

Composite thin films of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) decorated with Au or Ag nanoclusters and nanoparticles were fabricated at the interfaces of chloroform solution of PS-b-P2VP and aqueous solutions of HAuCl4 or AgNO3. Transmission electron microscopy (TEM) investigations indicated that large area of a single-layer honeycomb structure was formed, which is composed of polygons (most of them are hexagons) whose walls look like spindles with the length of several hundreds of nanometers. Large amount of Au or Ag nanoparticles are embedded in the walls and the undersides of the honeycomb structures. The formation of these novel composite structures was attributed to the adsorption of block copolymer molecules and inorganic species of AuCl4- and Ag+ ions at the liquid–liquid interface, the combination of the polymer molecules and the inorganic ions, and the self-assembly of the composite molecules. After UV-light irradiation and KBH4 aqueous solution treatment, the inorganic species were reduced completely, as confirmed by UV–vis spectra and X-ray photoelectron spectra. These composite films exhibited high catalytic activities for the reduction of 4-nitrophenol (4-NP) by KBH4 in aqueous solutions.