Abstract Polymer capsules capable of adopting distinct shell nanostructures in response to external stimuli are attractive microcompartments for encapsulation, separation, and triggered release. Realizing such capsules requires orthogonal control, in which distinct stimuli independently define the structural outcome. Here, we report a light- and temperature-programmed assembly strategy for hollow polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer (BCP) capsules with tunable shell nanostructures. The key to this dual responsiveness is a photocleavable thermoresponsive additive, in which an amide-based thermoresponsive backbone sets the transition temperature and a photocleavable comonomer encodes the light response. During emulsion-confined assembly, photocleavage shifts the lower critical solution temperature of the additive and redistributes it between the aqueous and organic phases, selecting either concentric lamellar or cylindrical shells at a given temperature. Replacing the poly(N-isopropylacrylamide) backbone with poly(N-isopropylmethacrylamide) raises the operating temperature from 27 to 50 °C, whereas replacing the o-nitrobenzyl group with a coumarin unit shifts photoactivation from 365 to 410 nm and reverses the direction of the light-driven morphology selection. This modular design offers a versatile strategy for programming BCP capsule shell morphologies under user-defined thermal and optical conditions.
Abstract Polyproline exists in two forms, the all-cis right-handed polyproline helix (type I) and the all-trans left-handed polyproline helix (type II). While the former is favored in common organic solvents, the latter is favored in aqueous solutions. Taking advantage of the hydrophilicity of type II polyproline, we prepared peptide-based nanostructures from a series of block copolymers of ε-caprolactone and l-proline. Copolymers were synthesized via N-carboxyanhydride polymerization in DMF using amino-ended polycaprolactone as initiator and covering a broad range of polyproline compositions. By simple stirring in water, the cis–trans isomerization of polyproline triggered their solubilization, leading to the spontaneous self-assembly of the copolymers into colloidally stable nanoparticles. Optical rotation measurements demonstrated the mutarotation of prolyl residues and circular dichroism spectroscopy shed light on the preferential type II secondary structure of polyproline that stabilizes nanostructures. Nanodevices encapsulated doxorubicin hydrochloride, highlighting their potential as drug delivery systems.
Abstract Rearranging hydrogels are used for applications that require tailored control of solid- and liquid-like properties. These applications necessitate pinpointing the phase transition, where a sample-spanning structure is formed or broken. To characterize the mechanical properties at the phase transition, we use time-cure superposition (TCS), which superimposes rheological properties as a function of increasing extents of gelation or degradation, p. We generally use reaction time to estimate p. However, dynamic materials undergo network rearrangements, which invalidates this assumption. In this work, we characterize the rheology of a rearranging hydrogel during degradation using multiple particle tracking microrheology (MPT). The logarithmic slope of the particle mean-squared displacements, α, is used to estimate p instead of time, because α is directly related to the cross-link density, ρ, and is independent of time. This reformulation identifies the phase transition unambiguously and more precisely, expanding the scope of the technique to quantify phase transitions in these types of hydrogels.
Abstract Traditional room-temperature phosphorescence (RTP) materials rely on complex aromatic structures. However, achieving efficient and long-lived emission from simple polymers remains an appealing but difficult challenge. Herein, we propose an acid-triggered crystallization strategy for acrylamide (AM) and hydroxyethyl methacrylate (HEMA) copolymers. The introduction of HCl drives the conversion of AM into 3-chloropropionamide (3-CPA) crystals and generates protonated nitrogen species, with the hydroxyl and ester groups from HEMA working synergistically to reinforce the hydrogen-bonding network. This structural evolution significantly boosts the overall crystallinity of the polymer network, reinforcing conformational rigidification and effectively restricting molecular motion. The strategy extends the emission lifetime from an initial 4.3 ns to 366 ms, accompanied by all overall photoluminescence quantum yield (PLQY) of 15.4%. The resulting poly(acrylamide-hydroxyethyl methacrylate) (PAMHE) derivative exhibits a green afterglow. This work offers a straightforward, metal-free paradigm for the design of high performance nontraditional RTP materials, holding immense promise for advanced anticounterfeiting applications.
Abstract A series of poly(4-vinylpyridine)-b-polystyrene-b-polydimethylsiloxane-b-polystyrene-b-poly(4-vinylpyridine) (P4VP-b-PS-b-PDMS-b-PS-b-P4VP, denoted as VxS104D69S104Vx) pentablock terpolymers with different length x (31, 46, 99, 145) of P4VP blocks were synthesized via two-step reversible addition–fragmentation chain transfer (RAFT) polymerization. Their bulk self-assembly behavior was investigated by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). With increasing P4VP block length, the equilibrium morphology evolved successively from tetragonally packed alternating P4VP/PDMS cylinders in the PS matrix (TETVD) to hexagonally packed alternating P4VP/PDMS cylinders with unequal coordination numbers (HEXVD), then to lamellae containing discontinuous PDMS subdomains (LAM), and finally to coexisting LAM and PDMS/PS core–shell hexagonally packed cylinders (CSHSD). Notably, the HEXVD phase represents, to our knowledge, the first experimental realization of a hexagonal cylinder phase with unequal coordination numbers in an ABCBA pentablock terpolymer system. The TETVD to HEXVD transition is governed by the compositional asymmetry and the topological constraint imposed by the doubly tethered middle PDMS block. These results demonstrate that tuning the terminal-block length in ABCBA pentablock terpolymers provides an effective route to unconventional three-phase nanostructures.
Most terpene-derived polymers reported to date are amorphous resins, elastomers, or cross-linked networks. Here we report a crystalline isotactic polyterpenoid, poly(4,8-dimethyl-1,7-nonadiene) (PDMND), synthesized from naturally abundant citronellal using a pyridylamido hafnium catalyst. Temperature-dependent WAXD reveals that PDMND adopts an isotactic-polypropylene-like (3/1) helical backbone with an axial repeat of ca. 6.6 Å. Unlike conventional semicrystalline polyolefins, the densely populated, nonlinear terpenoid side groups prohibit chain folding and promote the packing of fully extended bottlebrush-like rigid rods. DSC, WAXD, FTIR, and rheological analyses reveal reversible order-disorder transitions from an ordered cylindrical-rod crystal to a side-chain-disordered phase and further to a nematic-like crystalline state before melting. This work expands terpene-derived polymers from amorphous materials to crystalline stereoregular polyolefins with unusual bottlebrush-rod packing.
Abstract Here, we identify sterically exposed bromothiophene C–Br bonds in diketopyrrolopyrrole (DPP) monomers as monomer-level structural warning signs for hidden homocoupling defects in Migita–Stille-derived DPP–dithienylethene (DTE) polymers. High-temperature 1H NMR analysis revealed 11% DPP–DPP and 10% DTE–DTE linkages in a Stille-derived polymer represented by an alternating DPP–DTE repeat unit, whereas a locally hexyl-substituted structural comparator contained <1% and approximately 1%, respectively. Matched small-molecule Stille reactions reproduced the same substrate-dependent ordering in every catalyst system directly compared. Under Pd/P(o-tolyl)3 conditions, lowering the temperature decreased cross-coupling selectivity for the exposed substrate, but not the locally substituted analogue, thereby highlighting the elevated homocoupling susceptibility of exposed C–Br sites. Comparison of the homocoupling-rich Stille-derived polymer with a low-homocoupling Suzuki–Miyaura reference revealed distinct optical/electronic properties, thin-film organization, and transistor characteristics. These findings underscore the need to verify polymer linkage sequences experimentally rather than infer them from formally drawn repeat units or general expectations regarding coupling selectivity.
The self-assembly of associative triblock copolymers composed of a central hydrophilic elastin-like polypeptide (ELP) block and short fatty acid end groups (C16) was investigated in aqueous solution. In one system, the ELP contains 80 pentapeptide units (C16-80-C16), whereas in the other two C16-ELP40 chains were oxidatively coupled through their terminal cysteine residues to form a central disulfide bond, yielding C16-(40)2-C16. Despite their nearly identical molecular weights and compositions, the two polymers exhibit markedly different self-assembly behaviors. C16-80-C16 forms large hydrophobic aggregates that remain kinetically trapped and do not develop a dynamically connected network. In contrast, C16-(40)2-C16 forms very small associative nodes with an aggregation number of only ∼3 chains. These nodes coexist with larger clusters and become dynamically interconnected at higher concentrations, leading to transparent hydrogels at concentrations as low as 2.5 wt %. Oscillatory rheology reveals a transient Maxwell network governed by a single relaxation process associated with the reversible association of the C16 end groups. SAXS, light scattering, cryo-TEM, and molecular modeling consistently support a model in which the central disulfide junction promotes transient network formation.
Abstract Polymeric ionic liquids (i.e., PILs) have diverse sensing capabilities due to their potentially high ionic conductivity and tunable chemical response. However, integrating them into miniaturized sensor components often requires harsh nonaqueous developers, limiting eco-friendly microfabrication. To overcome this challenge, we designed a system that utilizes a UV-active thiol–ene click reaction to cross-link a photopatternable PIL, PAGE-TFSI–EMIm+, that enables device patterning under 365 nm exposure. This specific design leverages the material’s ionic nature to enable fully aqueous development, bridging the gap between precise microfabrication and processing with a lower environmental footprint in the development stage. The resulting films were successfully patterned with 12.8 μm resolution. As an independent proof-of-concept for the functional application of these materials, an impedance-type humidity sensor was fabricated by integrating interdigitated electrodes with patterned 3 mm-diameter PAGE-TFSI–EMIm+ films. The sensor demonstrated excellent sensitivity with low hysteresis (2.5% relative humidity (RH)) across a broad humidity range of 0–78% RH. Equivalent circuit fitting of electrochemical impedance spectroscopy (EIS) results suggest that the sensing mechanism is primarily governed by the variable ionic conductivity with humidity within the film. This approach underscores the potential of photopatterned PILs for advanced sensor architectures.
Abstract The efficient release of semiconducting single-walled carbon nanotubes (s-SWCNTs) from conjugated polymer wrappers via photoisomerization under light stimuli is attractive but has not been achieved yet and remains challenging. Herein, we report a photoisomerization polymer of PFDD-CS, by incorporating a cyano-styrene linker featuring a twisted conjugate structure. It can undergo only the desired trans-to-cis photoisomerization, but not the normal photocyclization nor photoaddition for cyano-styrene derivatives. Particularly, it can even occur in situ successfully on the nanotube surface under light stimuli, facilitating the release of bare s-SWCNTs. Experimental results revealed that the twisted conjugate structure of the initial trans-form contributes to the mobility on the surface of s-SWCNTs, while the significant conformational differences between the trans- and cis-isomers facilitate polymer detachment and bare s-SWCNT release. This work provides a mild, light-triggered strategy for obtaining pure nanotubes and advances the development of stimuli-responsive polymers for nanomaterials processing.
Ionizable lipids are key components of lipid nanoparticles for mRNA delivery. Inspired by the DLin-KC2-DMA ionizable lipid, we developed a series of pyrrole-based ionizable lipids to evaluate the feasibility of incorporating a rigid heterocyclic scaffold into ionizable lipid design. Systematic variation of headgroup architecture revealed that positioning the tertiary amine outside the pyrrole core substantially improved RNA encapsulation and transfection activity and identified lipid 6 as the lead structure within this series. Lipid nanoparticles formulated with lipid 6, administered via intramuscular injection, outperformed other pyrrole analogs and achieved lymph node transfection comparable to structural reference DLin-KC2-DMA. Mechanistic studies combining Förster resonance energy transfer assays and multiscale molecular dynamics simulations suggested that the improved delivery was associated with enhanced lipid-RNA electrostatic interactions and favorable membrane fusion behavior. Overall, this work establishes pyrrole as a feasible scaffold for ionizable lipid development and expands the chemical design space of mRNA delivery materials.
Developing nanomaterials from lignin and its derivatives represents an effective strategy for the high-value utilization of lignin; however, achieving template-free morphological control of lignin-based nanomaterials remains a significant challenge. Herein, we propose a strategy combining Scholl and demethylation reactions for the preparation of lignin-derived nanosheets using veratraldehyde-derived triarylimidazoles as the precursor. Oligomerization is achieved through the Scholl reaction of aromatic ring moieties, concurrent with the conversion of methoxy moieties to phenolic hydroxyl groups via demethylation.This dual mechanism enables the monomers to assemble into poly(phenol imidazole) nanosheets with a thickness of 5 nm, mediated by both covalent polymerization and noncovalent interactions. By incorporating these nanosheets into a poly(vinyl alcohol) matrix, the mechanical properties, thermal stability, and UV-shielding capabilities of the resulting composites are simultaneously enhanced. This work provides valuable insights into the high-value valorization of lignin and offers a novel template-free synthesis strategy for low-dimensional organic nanomaterials.
An epoxide 3-ethyl-6-(oxiran-2-yl)tetrahydro-2H-pyran-2-one, (EtOP) synthesized from a CO2/butadiene-derived lactone (3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one, EVP) is used in ring-opening copolymerization (ROCOP) with a series of anhydrides and carbon dioxide. Anhydride copolymerizations were carried out using the catalyst N,N-bis(salicylidene)-cyclohexanediamine chromium(III) chloride ((salen)CrCl) in combination with bis(triphenylphosphine)iminium chloride (PPNCl), resulting in high yields (> 75 %) of moderate molar mass (20-40 kDa) polyesters. The glass transition temperatures (Tg) of the polyesters could be modulated from 75 ºC (maleic anhydride, MA) to 112 ºC (norbornene anhydride, NA) whilst maintaining good thermal stability (Td > 180 ºC). These glass transition temperatures are significantly higher than other polyesters derived from EVP, which are typically <0 ºC. Reactions of EtOP with CO2 catalyzed by (salen)Co(OAc)/[PPN]TFA afforded polycarbonates with >99 % selectivity. The resultant polycarbonate has a CO2 content of 41 weight % (wt%), and its Tg value of 73 ºC represents the highest Tg reported for a material with a CO2 wt% above 40%
We report the segmental dynamics of poly(n-ethyl methacrylate) melts forming nanotubes inside cylindrical alumina nanopores (AAOs). Long nanotubes were fabricated at the inner pore walls by the polymer precursor film during the complete wetting transition at high temperatures. Using differential scanning calorimetry and dielectric spectroscopy, we show that the segmental dynamics in the nanotubes are bimodal and slower than in bulk with a broad distribution of relaxation times. These features reflect the dynamic properties of the "dead layer" formed by the adsorbed polymer chains at the pore walls.
Polymers containing heavy elements exhibit high refractive indices and excellent radiation shielding properties. However, a major challenge is their tendency to absorb visible light, leading to coloration and reduced transparency. To address this fundamental issue, we designed a bismuth-containing monomer that can undergo radical polymerization, in which the binding position of the polymerizable vinyl group was optimized, thereby introducing a novel molecular design that suppresses visible-light absorption. The resulting monomer underwent both thermal radical polymerization and photopolymerization, yielding a colorless, transparent, and self-supporting film that exhibited a high refractive index (nD) of 1.72 and excellent X-ray shielding properties equivalent to 1.67 μm-Al/μm-polymer. This study establishes a new strategy for the molecular design of high-refractive-index transparent materials containing heavy elements and significantly expands their applications in optical and X-ray shielding materials.
Achieving simultaneous control over the self-polarized β-phase and strain-amplifying microarchitectures in PVDF remains challenging. Here, we report a facile approach that introduces a deliquescent salt layer (e.g., CaCl2) during conventional spin-coating to address this issue. In this process, most deliquescent salt is trapped near the membrane bottom interface, while a minor fraction migrates toward the top surface. The resulting asymmetric salt distribution draws in ambient moisture, establishing a vertical water gradient that drives in situ nonsolvent-induced phase separation (NIPS), wherein cooperative interactions (hydrogen bonding, ion-dipole, and dipole-dipole) align PVDF chains into the self-polarized β-phase. After removing the residual salt from the membrane, an asymmetric porous architecture is formed. Under identical tapping conditions, this membrane produces a stable piezoelectric output of ∼3.69 V, outperforming KBr-based counterparts (∼1.65 V) and nondeliquescent salt systems. This low-cost, scalable strategy eliminates the need for expensive substrates or equipment, offering a practical route to high-performance flexible piezoelectric devices.
Efficiently eradicating superbacteria without harming normal cells and inducing bacterial drug-resistance holds significant importance in safeguarding human health. Herein, we discovered a novel selective bactericidal material synthesized from natural cellulose as the backbone, with cationic groups introduced via a deoxygenation process. Compared to conventional ester-type cationic cellulose derivatives (CCDs), deoxy-type CCDs exhibit high selective bactericidal activity. Through tailored cationic structure and substitution degree modulation, these derivatives achieve targeted bacterial eradication at low concentrations while maintaining mammalian cell biocompatibility. Specifically, deoxy-type CCDs, C-Ts-BenA0.80 and C-Ts-TBuP0.83, demonstrate minimum inhibitory concentrations (MICs) of 16 μg/mL and 4 μg/mL against E. coli and S. aureus, respectively, with corresponding selectivity indices of 312 and 50. Deoxy-type CCDs have strong cell-membrane depolarization ability owing to the unique surface charge distribution, thus leading to bacterial death. Based on the physical membrane-disruption mechanism, deoxy-type CCDs do not induce the emergence of drug-resistant bacteria and can effectively kill a variety of superbugs, including ESKAPE bacteria. The synergistic effect between the linkage bond and cations offers a new approach for constructing highly efficient and nontoxic inactivating materials.
The development of neutral silicon-based Lewis acids (LAs) has gained increasing attention, their use as catalysts for polymerization reactions has not yet been reported. Herein, we report a neutral silicon-based Lewis pair (LP) catalytic system composed of Si(catR)2 (R = H, Cl, Br, tBu) LAs and N-heterocyclic olefin (NHO) for the living polymerization of acrylamide monomers. The coordination behavior between monomers and Si(catR)2 with varying Lewis acidities was elucidated by single-crystal X-ray diffraction and in situ NMR analysis. The Si(catH)2/NHO pair exhibited high catalytic activity and control under ambient conditions, enabling the polymerization of N,N-dimethylacrylamide with high molecular weights (up to 576 kg·mol-1) and low dispersities (Đ = 1.13-1.22). MALDI-TOF-MS and chain-extension studies confirmed the living nature of the system. The scope was extended to other acrylamides, including N,N-diethylacrylamide and N,N-diallylacrylamide, allowing the synthesis of well-defined block copolymers with preserved pendant functionality and clear microphase separation behavior as confirmed by DSC. This work constructs a metal-free neutral silicon-based Lewis pair catalytic platform dedicated to the controlled synthesis of polyacrylamides, expands the library of main-group Lewis pair catalysts, and offers a novel synthetic strategy for fabricating functional precision polymers available for postpolymerization modification.
The synthesis of ultrahigh-molecular-weight polyethylene (UHMWPE) is often hampered by the inherent compromise in traditional catalysts, such as Ziegler-Natta systems, which struggle to balance high activity with precise control over molecular parameters. Covalent organic frameworks (COFs) offer a promising alternative, allowing for atomic-level design through their tunable pores and microenvironments. In this work, we address this challenge by designing a series of Zr@COF catalysts─denoted as Zr@PQ-TFPB (O-Zr-O), Zr@PQSO-TFPB (N-Zr-O), and Zr@PQDO-TFPB (N-Zr-N)─to systematically investigate the role of the coordination environment. Spectroscopic and catalytic studies reveal that the N-Zr-N configuration in Zr@PQDO-TFPB optimally reduces the electron density at the Zr center. This electronic modulation, characterized by reduced electron density at the Zr center, facilitates ethylene adsorption/insertion while suppressing β-H elimination, leading to a superior polymerization activity of 3.87 × 105 g·molZr-1·h-1 at 3.0 MPa─66% and 38% higher than its O-Zr-O and N-Zr-O analogues, respectively. This catalyst produces UHMWPE with a high molecular weight of 1.71 × 106 g·mol-1 and a relatively narrow dispersity (Đ = 2.2). Furthermore, the rigid nanochannels of the COF provide a confining effect that stabilizes the growing polyethylene chains. Our findings underscore a critical synergy between coordination-induced electronic effects and spatial nanoconfinement, providing a novel design principle for next-generation polyolefin catalysts.
Targeted protein degradation mediated by antibodies represents a powerful approach for eliminating cell surface proteins. However, most existing systems require the customized conjugation of antibodies to functional groups that mediate cellular endocytosis, thereby lacking structural universality and expandability. Herein, we developed a modular glyco-nanosheet platform for GLUT1-facilitated lysosomal degradation of cell-surface immune checkpoints, integrating a glucosyl polymer module for tumor-specific endocytosis and a protein A (ProA) module for universal antibody loading. By programming the spatial distribution of functional modules, we constructed three nanostructures with tunable antibody density and distribution. These nanosheets enabled efficient GLUT1-facilitated internalization and lysosomal trafficking, resulting in an effective single-target degradation of PD-L1 and simultaneous dual-target degradation of PD-L1/CD47. Under IFN-γ cotreatment, the dual-target nanosheets reduced the relative viability of cancer cells to ∼30%, significantly outperforming single-target systems. This modular, target-expandable glyco-nanosheet provides a universal strategy for multitargeted TPD and shows great potential for precision immunotherapy.
