Explore the vast range of titles available.

The self-assembly of block polymers into well-ordered nanostructures underpins their utility across fundamental and applied polymer science, yet only a handful of equilibrium morphologies are known with the simplest AB-type materials. Here, we report the discovery of the A15 sphere phase in single-component diblock copolymer melts comprising poly(dodecyl acrylate)−block−poly(lactide). A systematic exploration of phase space revealed that A15 forms across a substantial range of minority lactide block volume fractions (f L = 0.25 − 0.33) situated between the σ-sphere phase and hexagonally close-packed cylinders. Self-consistent field theory rationalizes the thermodynamic stability of A15 as a consequence of extreme conformational asymmetry. The experimentally observed A15−disorder phase transition is not captured using mean-field approximations but instead arises due to composition fluctuations as evidenced by fully fluctuating field-theoretic simulations. This combination of experiments and field-theoretic simulations provides rational design rules that can be used to generate unique, polymer-based mesophases through self-assembly.

The polyethylene oxide‐polypropylene oxide (PEO‐PPO) based triblock copolymers are notable amphiphilic copolymers with a diverse range of applications. The presence of homo‐, and/or diblock impurities in copolymers with PEO‐PPO‐PEO triblock has been demonstrated. This finding suggests that the samples are blends rather than pure triblock copolymers. Furthermore, copolymers with triblock copolymer content of 0 or less than 20% by molar percentage have been identified. The hydrophilic‐lipophilic balance (HLB) is also calculated based on the exact composition of the blends. The effect of HLB values and compositional data on the initial foam height (in casein solution), the surface tension, and the contact angle are investigated. The correlation coefficients for the PPO‐PEO‐PPO copolymers versus HLB values are found to be high, while those obtained for the PEO‐PPO‐PEO copolymers versus values of HLB are significantly lower. The lower correlation coefficients for the PEO‐PPO‐PEO samples can be attributed to the presence of homo‐ and diblock (co)polymer contaminants. In addition, a linear regression model has been constructed to find a mathematical relationship between the percentage of ethylene oxide, the average number of propylene oxide units, and the properties of the copolymer. It is found that polyethylene oxide – polypropylene oxide (PEO‐PPO) triblock copolymers contain homopolymer and diblock copolymers, the tested samples are copolymer blends. This sheds new light on the structure‐physical property relationship. To map this relationship, HLB values are used, calculated from the determined composition. A good correlation is found between composition‐physical properties as determined by detailed analysis.

Molecular photoswitches are incorporated into materials to impart photoresponsiveness, enabling a wide range of fascinating applications. Although their surrounding environments within materials strongly influence the photoresponsive and thermally reversible behaviors through physical and chemical interactions, these effects remain poorly understood. In this study, we investigate the two-way photoisomerization and thermal back-isomerization of spiropyran (SP)-a representative photoswitch that undergoes large polarity changes upon the reversible isomerization to merocyanine (MC)-chemically integrated into diblock copolymers (dBCPs) exhibiting either ordered or disordered microphase separation. We synthesize a series of dBCPs consisting of a high-glass-transition-temperature ( ) poly(methyl methacrylate) block and a low- statistical copolymer block of SP acrylate and -butyl acrylate, with varying compositions, molecular weights, and microphase-separated structures. The results reveal that the rates of both the SP-to-MC and MC-to-SP photoisomerization processes differ substantially between ordered and disordered microphase-separated structures but are comparable among the different ordered morphologies. In contrast, the photoisomerization yields are scarcely affected by the microphase separation. These findings provide valuable insights into the molecular and polymer design of photoresponsive smart materials based on photoswitches and will contribute to their further development and applications.

A laboratory-synthesized triblock copolymer poly(ethylene oxide-b-acrylic acid-b-styrene) (PEG-PAA-PS) was used as a template to synthesize hollow BaCO3 nanoparticles (BC-NPs). The triblock copolymer was synthesized using reversible addition–fragmentation chain transfer radical polymerization. The triblock copolymer has a molecular weight of 1.88 × 104 g/mol. Transmission electron microscopy measurements confirm the formation of spherical micelles with a PEG corona, PAA shell, and PS core in an aqueous solution. Furthermore, the dynamic light scattering experiment revealed the electrostatic interaction of Ba2+ ions with an anionic poly(acrylic acid) block of the micelles. The controlled precipitation of BaCO3 around spherical polymeric micelles followed by calcination allows for the synthesis of hollow BC-NPs with cavity diameters of 15 nm and a shell thickness of 5 nm. The encapsulation and release of methotrexate from hollow BC-NPs at pH 7.4 was studied. The cell viability experiments indicate the possibility of BC-NPs maintaining biocompatibility for a prolonged time.

Over the past decade, controlled supramolecular polymerization has been extensively studied and gradually shifted to supramolecular block copolymerization. Supramolecular block copolymers (BCPs) are considered the holy grail for developing supramolecular materials with new functionalities due to their fascinating structures and ability to introduce diverse functions. From a thermodynamic view to kinetic aspects, great progress has been made in the synthetic strategies of BCPs in the past few years. This Concept summarizes various strategies to realize supramolecular block copolymerization. The focus is on providing researchers with a methodological basis for achieving heterogeneous nucleation‐elongation. By dissecting representative examples in supramolecular block copolymerization, this Concept systematically discusses different strategies to realize block copolymerization and provides general insights into the preparation of supramolecular BCPs. A good comprehension of these examples will facilitate the development of BCPs with novel composite functions.

Recently, the interest in charged polymers has been rapidly growing due to their uses in energy storage and transfer devices. Yet, polymer electrolyte-based devices are not on the immediate horizon because of the low ionic conductivity. In the present study, we developed a methodology to enhance the ionic conductivity of charged block copolymers comprising ionic liquids through the electrostatic control of the interfacial layers. Unprecedented reentrant phase transitions between lamellar and A15 structures were seen, which cannot be explained by well-established thermodynamic factors. X-ray scattering experiments and molecular dynamics simulations revealed the formation of fascinating, thin ionic shell layers composed of ionic complexes. The ionic liquid cations of these complexes predominantly presented near the micellar interfaces if they had strong binding affinity with the charged polymer chains. Therefore, the interfacial properties and concentration fluctuations of the A15 structures were crucially dependent on the type of tethered acid groups in the polymers. Overall, the stabilization energies of the A15 structures were greater when enriched, attractive electrostatic interactions were present at the micellar interfaces. Contrary to the conventional wisdom that block copolymer interfaces act as “dead zone” to significantly deteriorate ion transport, this study establishes a prospective avenue for advanced polymer electrolyte having tailor-made interfaces.

Dissipative particle dynamics (DPD) simulations is used to study the effect of Am/2BmAm/2 and H-shaped (Am/4)2Bm(Am/4)2 block copolymers on the interfacial properties of ternary blends. Our simulations show the following: (i) The capacity of block copolymers to diminish interfacial tension is closely linked to their compositions. With identical molecular weights and concentrations, H-shaped block copolymers outperform triblock copolymers in mitigating interfacial tension. (ii) The interfacial tension within the blends correlates positively with the escalation in H-shaped block copolymer molecular weight. This correlation suggests that H-shaped block copolymers featuring a low molecular weight demonstrate superior efficacy as compatibilizers when contrasted with those possessing a high molecular weight. (iii) Enhancing the concentration of H-shaped block copolymers fosters their accumulation at the interface, leading to a reduction in correlations between immiscible homopolymers and a consequent decrease in interfacial tension. (iv) As the length of the homopolymer chains increases, there is a concurrent elevation in interfacial tension, suggesting that H-shaped block copolymers perform more effectively as compatibilizers in blends characterized by shorter homopolymer chain lengths. These findings elucidate the associations between the efficacy of H-shaped block copolymer compatibilizers and their specific molecular characteristics.

4-Phenylbutyric acid (PBA) is a small molecule with promising therapeutic potential for treating various diseases, including cancer and neurodegenerative disorders, due to its dual ability to reduce endoplasmic reticulum stress and inhibit histone deacetylases. However, its clinical application is hindered by rapid clearance from the body, necessitating frequent dosing that increases the risk of adverse effects. To address these limitations, we developed a nanoparticle-based prodrug (Nano ) utilizing the amphiphilic block copolymer poly(ethylene glycol)- -poly(vinyl 4-phenylbutyrate) [PEG- -P(VPBA)]. This system self-assembles into micelles, enabling controlled and sustained PBA delivery. The synthesis and characterization of Nano revealed its high stability under physiological conditions and enzyme-responsive PBA release. Nano demonstrated a controlled release profile , reducing burst release while maintaining therapeutic efficacy. Cytotoxicity assays using normal cell lines, including endothelial cells (BAEC), macrophages (RAW264.7), and rat gastric cells (RGM-1), showed minimal cytotoxic effects compared to the parent low-molecular-weight PBA. Furthermore, studies conducted in healthy C57BL/6J mice confirmed Nano 's biocompatibility, with no significant adverse effects observed at therapeutic doses ranging from 200 to 500 mg-PBA/kg via oral administration. In conclusion, Nano offers a controlled release profile, enhanced biocompatibility, and reduced toxicity, addressing the limitations associated with conventional PBA administration. These attributes make Nano a promising candidate for improving the therapeutic efficacy and safety of PBA in clinical applications, particularly in diseases where maintaining consistent drug levels is crucial for treatment outcomes.

We explore the generality of the influence of segment chirality on the self-assembled structure of achiral–chiral diblock copolymers. Poly(cyclohexylglycolide) (PCG)-based chiral block copolymers (BCPs*), poly(benzyl methacrylate)-b-poly(D-cyclohexylglycolide) (PBnMA-PDCG) and PBnMA-b-poly(L-cyclohexyl glycolide) (PBnMA-PLCG), were synthesized for purposes of systematic comparison with polylactide (PLA)-based BCPs*, previously shown to exhibit chirality transfer from monomeric unit to the multichain domain morphology. Opposite-handed PCG helical chains in the enantiomeric BCPs* were identified by the vibrational circular dichroism (VCD) studies revealing transfer from chiral monomers to chiral intrachain conformation. We report further VCD evidence of chiral interchain interactions, consistent with some amounts of handed skew configurations of PCG segments in a melt state packing. Finally, we show by electron tomography [3D transmission electron microscope tomography (3D TEM)] that chirality at the monomeric and intrachain level ultimately manifests in the symmetry of microphase-separated, multichain morphologies: a helical phase (H*) of hexagonally, ordered, helically shaped tubular domains whose handedness agrees with the respective monomeric chirality. Critically, unlike previous PLA-based BCP*s, the lack of a competing crystalline state of the chiral PCGs allowed determination that H* is an equilibrium phase of chiral PBnMA-PCG. We compared different measures of chirality at the monomer scale for PLA and PCG, and argued, on the basis of comparison with mean-field theory results for chiral diblock copolymer melts, that the enhanced thermodynamic stability of the mesochiral H* morphology may be attributed to the relatively stronger chiral intersegment forces, ultimately tracing from the effects of a bulkier chiral side group on its main chain.

After many years of development, block copolymers became one of the most important materials for organic solar cells. They were used in photovoltaic cells because of their self-assembly properties and controlled ordered nanoscale, which is ideal for electron-hole pair separation. However, block copolymers still faced several major challenges as organic solar materials, and this paper focused on their limitations and corresponding solutions in terms of material design, morphology control, and interface modification, as well as on the fundamental molecular engineering principles involved. In the paper’s conclusion, an perspective on the use of modern, advanced block copolymers in organic solar cells was provided.