The ring-opening alternating copolymerization (ROAC) of 3,4-dihydrocoumarin (DHC)/epoxides has been successfully developed using an imidazolium salt of 1-ethyl-3-methylimidazolium chloride (EMIMCl) as a catalyst. The resulting copolymer has a molecular weight of 13.7 kg·mol^–1, a narrow molecular weight distribution of 1.03 and a strictly alternating structure. The MALDI-TOF MS characterization and DFT calculations including electrostatic potential (ESP), hydrogen-atom abstraction (HAA), independent gradient model based on hirshfeld partition (IGMH) and atoms-in-molecules (AIM) analysis were used to investigate the metal-free catalytic process. The synergistic effect of anions and cations of EMIMCl for ROAC of DHC and epoxides was demonstrated. This study provides a metal-free catalytic system for the facile synthesis of alternating polyesters from DHC.

Numerous efforts have been devoted to altering the dynamic covalent linkers between the drug structural units in polyprodrugs from the viewpoint of molecular structure; however, the effect of their aggregation states has not yet been explored. Here, the effect of aggregation states on the in vitro drug release and cytotoxicity was investigated using a pH/glutathione (GSH) co-triggered degradable doxorubicin (DOX)-based polyprodrug (PDOX) as a model, which was synthesized by the facile polymerization of a pH/GSH dual-triggered dimeric prodrug (DDOX_ss) and 2,2-dimethoxypropane (DMP) by forming acid-labile ketal bond. Owing to the pH/GSH dual-triggered disulfide/α-amide and acid-labile ketal linkers between the DOX structural units, the resultant PDOX exhibited excellent pH/GSH co-triggered DOX release. With a similar diameter, the PDOX-NPs1 nanomedicines via fast precipitation showed faster DOX release than PDOX-NPs2 via slow self-assembly, regardless of their polymerization degree (DP). The effect of aggregation states is expected to be a secondary strategy for a more desired tumor intracellular microenvironment-responsive drug delivery for tumor chemotherapy, in addition to the molecular structures of polyprodrugs as drug self-delivery systems (DSDSs).

In recent years, cellulose-based fluorescent polymers have received considerable attention. However, conventional modification methods face challenges such as insolubility in most solvents, fluorescence instability, and environmental risks. In this study, a novel biosynthesis strategy was developed to fabricate fluorescent cellulose by adding fluorescent glucose derivatives to a bacterial fermentation broth. The metabolic activity of bacteria is utilized to achieve in situ polymerization of glucose and its derivatives during the synthesis of bacterial cellulose. Owing to the structural similarity between triphenylamine-modified glucose (TPA-GlcN) and glucose monomers, the TPA-GlcN were efficiently assimilated by the bacterial cells and incorporated into the cellulose matrix, resulting in a uniform distribution of fluorescence. The fluorescence color and intensity of the obtained cellulose could be adjusted by varying the amount of the fluorescent glucose derivatives. Compared to the fluorescent cellulose synthesized through physical dyeing, the fluorescence of the products obtained by in situ polymerization showed higher intensity and stability. Furthermore, fluorescent bacterial cellulose can be hydrolyzed into nanocellulose-based ink, which demonstrates exceptional anti-counterfeiting capabilities under UV light. This biosynthesis method not only overcomes the limitations of traditional modification techniques but also highlights the potential of microbial systems as platforms for synthesizing functional polymers.

Intracellular polymerization is an emerging field, showcasing high diversity and efficiency of chemistry. Motivated by the principles of natural biomolecular synthesis, polymerization within living cells is believed to be a powerful and versatile tool to modulate cell behavior. In this review, we summarized recent advances and future trends in the field of intracellular polymerization, specifically focusing on covalent and supramolecular polymerization. This discussion comprehensively covers the diverse chemical designs, reaction mechanisms, responsive features, and functional applications. Furthermore, we also clarified the connection between preliminary design of polymer synthesis and their subsequent biological applications. We hope this review will serve as an innovative platform for chemists and biologists to regulate biological functions in practical applications and clinical trials.

Consisting of natural histidine residues, polyhistidine (PHis) simulates functional proteins. Traditional approaches towards PHis require the protection of imidazole groups before monomer synthesis and polymerization to prevent degradation and side reactions. In the contribution, histidine N-thiocarboxyanhydride (His-NTA) is directly synthesized in aqueous solution without protection. With the self-catalysis of the imidazole side group, the ring-closing reaction to form His-NTA does not require any activating reagent (e.g., phosphorus tribromide), which is elucidated by density functional theory (DFT) calculations. His-NTA directly polymerizes into PHis bearing unprotected imidazole groups with designable molecular weights (4.2−7.7 kg/mol) and low dispersities (1.10−1.19). Kinetic experiments and Monte Carlo simulations reveal the elementary reactions and the relationship between the conversion of His-NTA and time during polymerization. Block copolymerization of His-NTA with sarcosine N-thiocarboxyanhydride (Sar-NTA) demonstrate versatile construction of functional polypept(o)ides. The triblock copoly(amino acid) PHis-b-PSar-b-PHis is capable to reversibly coordinate with transition metal ions (Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) to form pH-sensitive hydrogels.

To enhance the properties of bio-based polyesters, enabling them to more closely mimic the characteristics of terephthalate-based materials, a series of aliphatic-aromatic copolyesters (P₁–P₄) were synthesized via melt polycondensation. Diester monomers M and N were synthesized via the Williamson reaction, using lignin-derived 2-methoxyhydroquinone, methyl 4-chloromethylbenzoate, and methyl chloroacetate as starting materials. Hydroquinone bis(2-hydroxyethyl)ether (HQEE) and 1,4-cyclohexanedimethanol (CHDM) were employed as cyclic segments, while 1,4-butanediol (BDO) and 1,6-hexanediol (HDO) served as alkyl segments within the copolymer structures. The novel copolyesters exhibited molecular weights (M_w) in the range of 5.25×10⁴–5.87×10⁴ g/mol, with polydispersity indices spanning from 2.50–2.66. Evaluation of the structural and thermomechanical properties indicated that the inclusion of alkyl segments induced a reduction in both crystallinity and molecular weight, while significantly improving the flexibility, whereas cyclic segments enhanced the processability of the copolyesters. Copolyesters P₁ and P₂, due to the presence of rigid segments (HQEE and CHDM), displayed relatively high glass transition temperatures (T_g>80 °C) and melting temperatures (T_m>170 °C). Notably, P₂, incorporating CHDM, exhibited superior elongation properties (272%), attributed to the enhanced chain mobility resulting from its trans-conformation, while P₁ was found to be likely brittle owing to excessive chain stiffness. Biodegradability assessment using earthworms as bioindicators revealed that the copolyesters demonstrated moderate degradation profiles, with P₂ exhibiting a degradation rate of 4.82%, followed by P₄ at 4.07%, P₃ at 3.65%, and P₁ at 3.17%. The higher degradation rate of P₂ was attributed to its relatively larger d-spacing and lower toxicity, which facilitated enzymatic hydrolytic attack by microorganisms. These findings highlight the significance of optimizing the structural chain segments within aliphatic-aromatic copolyesters. By doing so, it is possible to significantly enhance their properties and performance, offering viable bio-based alternatives to petroleum-based polyesters such as polyethylene terephthalate (PET).

Poly(vinyl alcohol) (PVA) is a biodegradable and environmentally friendly material known for its gas barrier characteristics and solvent resistance. However, its flammability and water sensitivity limit its application in specialized fields. In this study, phytic acid (PA) was introduced as a halogen-free flame retardant and biochar (BC) was introduced as a reinforcement to achieve both flame resistance and mechanical robustness. We thoroughly investigated the effects of BC particle sizes (100−3000 mesh) and addition amounts (0 wt%−10 wt%), as well as PA addition amounts (0 wt%−15 wt%), on the properties of PVA composite films. Notably, the PA10/1000BC5 composite containing 10 wt% PA and 5 wt% 1000 mesh BC exhibited optimal properties. The limiting oxygen index increased to 39.2%, and the UL-94 test achieved a V-0 rating. Additionally, the PA10/1000BC5 composite film demonstrated significantly enhanced water resistance, with a swelling ratio reaching 800% without dissolving, unlike that of the control PVA. The water contact angle was 70°, indicating that hydrophilic properties remained essentially unaffected. Most importantly, the tensile modulus and elongation at break were 213 MPa and 281.7%, respectively, nearly double those of the PVA/PA composite film. This study presents an efficient and straightforward method for preparing PVA composite films that are flame-retardant, tough, and water-resistant, expanding their potential applications in various fields.

In this study, epoxidized soybean oil (ESO) and ricinoleic acid (RA) were used to synthesize polyol esters, designated ESO-RA (ER) resin. The esters were further crosslinked with 4,4-diphenylmethane diisocyanate (PMDI) to create a biodegradable flame-retardant thermoset foam, referred to as ESO-RA-PMDI (ERP) foam, using water as a foaming agent. Additionally, flame retardants such as triethyl phosphate (TEP) and expanded graphite (EG) have been combined for foam preparation without the need for catalysts or foaming agents. The study findings showed that the incorporation of TEP and EG diminished the pulverization ratio while augmenting the compressive strength and shore hardness. Furthermore, the ERP foam exhibited exceptional flame retardant characteristics, as evidenced by a reported limiting oxygen index (LOI) value of 30.6 vol%. A peak heat release rate of 97.12 kW/m² was reported during the fire test. Significantly, a low peak smoke production rate (pSPR) of 0.026 m²/s and a total smoke production (TSP) of 0.62 m² were achieved. In addition, ERP foam exhibited exceptional ultraviolet (UV) resistance, thermal insulation, and biodegradability. After 60 days of exposure to Penicillium sp., foam containing both TEP and EG exhibited a mass loss of 9.39%, indicating that the incorporation of flame retardants did not negatively impact its biodegradability.

The synthesis of functionalized rubber copolymers is a topic of great research interest. In this study, we present a novel approach for the direct construction of α-functionalized 3,4-polyisoprene through polymerization of polar monomers and isoprene monomer. The α-functionalized 3,4-polyisoprene was successfully synthesized via in situ sequential polymerization using the iron-based catalytic system (Fe(acac)₃/IITP/AlⁱBu₃), exhibiting high activity and resistance to polar monomers without requiring protection of polar groups. The structure of α-functionalized 3,4-polyisoprene was confirmed by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) spectra analysis. The introduction of polar groups, particularly hydroxyl groups, enhanced the hydrophilicity of the copolymer. This was evidenced by a decrease in the water contact angle from 106.9° to 96.4° with increasing hydroxyl content in the copolymer.

Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites; however, traditional compatibilization by copolymers (pre-made or in-situ generation) suffers from weak interface anchoring, and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy, while their low affinity to bulk components is a drawback. In this study, an interfacial atom transfer radical polymerization (ATRP) technique was employed to grow polystyrene (PS) and poly(2-hydroxyethyl methacrylate)(PHEMA) simultaneously on different hemispheres of Br-functionalized SiO₂ nanoparticles to stabilize a Pickering emulsion, whereby a brush-type Janus nanoparticle (SiO₂@JNP) was developed. The polymer brushes were well-characterized, and the Janus feature was validated by transmission electron microscope (TEM) observation of the sole hemisphere grafting of SiO₂-PS as a control sample. SiO₂@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate) (PMMA) immiscible blend, and the droplet-matrix morphology was significantly refined. The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO₂@JNP optimized ~0.9 wt%, with the tensile strength, elongation at break and impact strength increased by 17.7%, 26.6% and 19.6%, respectively. This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.

High mortality of choroidal melanoma (CM) is mainly attributed to the high likelihood of tumorous recurrence. The essential challenge lies in the presence of residual CM cells survived from the antitumor treatment. These residual tumorous cells are most likely to cause tumorous recurrence. This article reports the preparation of a multifunctional nanocomposite which can be used to treat CM efficiently via a chemotherapy-assisted-photothermal therapy (CTH-PTT). The nanocomposite comprises of alpha-tocopheryl succinate (α-TOS) and carboxylic chitosan modified graphene (CG). α-TOS has been potentially seen as an efficient CTH antitumor drug while its deficiency such as easy being hydrolyzed by gastrointestinal esterase and poor hydrophilicity inevitable limits the clinic application of α-TOS. CG is introduced to overcome these shortcomings, offering additional advantages such as the PTT possibility for the antitumor application. The employment of CG-α-TOS on ocular CM cells caused more than 80% inhibition rates after irradiation under an 808 nm laser for 10 min. The outcomes of this work provide a facile and advantageous way to resolve the essential issue of the treatment of ocular tumors such as CM.

The slow phase transition from form II to form I has always been an important factor that restricts the processing and application of polybutene-1 (PB-1). After extensive efforts, a set of effective methods for promoting the phase transition rate in PB-1 was established by adjusting the crystallization, nucleation, and growth temperatures. Nevertheless, low-molecular-weight PB-1 (LMWPB-1) faces challenges because this method requires a low crystallization temperature, which is difficult to achieve during extrusion processing. In this study, we attempted to increase the phase transition rate in PB-1 by changing the annealing temperature after processing rather than the crystallization temperature in the classical scheme. The results indicated that regardless of low- or high-molecular-weight PB-1, repeated annealing between 0 and 90 ^oC could also promote form II to form I phase transition. The initial content of form I increased with the heating and cooling cycles. The half-time of the phase transition (t_1/2) was also shortened after heating/cooling. After 100 heating/cooling cycles, t_1/2 was reduced to one-quarter of that without annealing, which had almost the same effect as the crystallization temperature at 25 °C in promoting the phase transition. This study indicates that annealing after processing is also an important factor affecting the phase transition of PB-1, and should receive sufficient attention.

Highly oriented poly(vinylidene fluoride) (PVDF) ultrathin films with different β-phase contents were prepared using the melt-draw method. The effect of β-phase content on α-β phase transition of highly oriented PVDF ultrathin films induced by stretching was investigated using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The results show that stretching can enhance the crystallinity and increase the average thickness of the lamellae. A full α-β phase transition can be achieved for PVDF ultrathin films of 20.6% β phase stretched to a λ (stretching ratio) of 1.5, while few α phases still exist for ultrathin films of 35.0% β phase, together with bent and tilted lamellae. Compared to thicker PVDF films undergoing stretching-induced α-β phase transition, the higher α-β phase transition efficiency of the PVDF ultrathin films can be attributed to the parallel aligned lamellar structure. Moreover, a higher β-phase content can suppress α-β phase transition because of the stress concentration effect of β-phase. Ultimately, these results provide valuable insights into the stretching-induced α-β phase transition of PVDF ultrathin films.

Thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (PNIPAm) often undergo syneresis upon heating, and thus become irrecoverable in shape. To overcome this limitation, we copolymerize tetra-armed PNIPAm precursor with tetra-armed poly(ethylene glycol) (PEG) precursor. After incorporating the hydrophilic PEG components, the hydrogel samples exhibited recoverable swellability during repeated heating-cooling cycles, during which phase segregation occurred, and the water repelled from the PNIPAm-rich phase can be accommodated in the PEG-rich phase. As a result, recoverability relied on the swellability of the PEG-rich phase, which correlated quantitatively with the molar mass and concentration of the precursor solution. This study provides an effective protocol for the molecular design of stimuli-responsive hydrogels with a desired degree of shape recoverability.

Spatial confinement of block copolymers can induce frustrations, which can further be utilized to regulate self-assembled structures, thus providing an efficient route for fabricating novel structures. We studied the self-assembly of AB di-block copolymers (di-BCPs) confined in Janus spherical nanocavities using simulations, and explained the structure formation mechanisms. In the case of a strongly selective cavity wall, all the lamella-forming, gyroid-forming, and cylinder-forming di-BCPs can form interfacial frustration-induced Janus concentric perforated lamellar nanoparticles, whose outermost is a Janus spherical shell and the internal is a sphere with concentric perforated lamellar structure. In particular, Janus concentric perforated lamellar nanoparticles with holes distributed only near the equatorial plane were obtained in both lamella-forming and gyroid-forming di-BCPs, directly reflecting the effect of interfacial frustration. The minority-block domain of the cylider-forming di-BCPs may form hemispherical perforated lamellar structures with holes distributed in parallel layers with a specific orientation. For symmetric di-BCPs, both the A and B domains in each nanoparticle are continuous, interchangeable, and have rotational symmetry. While for gyroid-forming and cylinder-forming di-BCPs, only the majority-block domains are continuous in each nanoparticle, and holes in the minority-block domains usually have rotational symmetry. In the case of a weakly selective cavity wall, the inhomogeneity of the cavity wall results in structures having a specific orientation (such as flower-like and branched structures in gyroid-forming and cylinder-forming di-BCPs) and a perforated wetting layer with uniformly distributed holes. The novel nanoparticles obtained may have potential applications in nanotechnology as functional nanostructures or nanoparticles.

The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering. Herein, a series of high-strength, recyclable fluorine-containing adhesives (ESO_x-FPF) were designed and synthesized by crosslinking two prepolymers, FPF-B (derived from side-chain fluorinated diol, isocyanate, and aminoboric acid) and ESO-B (synthesized from bio-based epoxy soybean oil and aminoboric acid), through dynamic boro-oxygen bonds. The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa. More importantly, benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction, ESO_x-FPF can be welded with the assistance of solvents and recycled for multiple cycles. The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing. Moreover, the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates, such as aromatic polyamide, aluminum plates and polycarbonate, meanwhile, they could be easily disassembled and recycled using ethanol without damaging the substrates surface. This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties, but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.

In high-frequency electrical energy systems, polyimide (PI) composite insulation materials need to possess a low dielectric constant, sufficient thermal conductivity, and robust interfacial adhesion to ensure reliable performance under elevated temperatures and pressures. These aspects are crucial for preventing local overheating and electrical breakdown, thereby ensuring reliable equipment operation. Traditional PI insulation materials often exhibit high dielectric constants and pronounced dielectric losses, compromising their insulation efficiency. In this study, molecular dynamics simulations were employed to incorporate polyhedral oligomeric silsesquioxanes (POSS) into PI through physical blending and chemical bonding to enhance dielectric properties. Key parameters of the PI/POSS composite system, including dielectric constant, thermal conductivity, glass transition temperature, Young’s modulus, Poisson’s ratio, and interfacial adhesion energy, were systematically evaluated for both doping methods. The degradation behavior of the PI composites under high-temperature and electric field conditions was also simulated to elucidate degradation pathways and product distributions, providing insights for designing low-dielectric insulation materials. Doping with POSS significantly reduces the dielectric constant of PI, thereby improving insulation performance, thermal stability, mechanical strength, and interfacial adhesion. At an optimal POSS doping ratio, the thermal conductivity of PI is enhanced. Compared with the physical blending system, the chemical bonding system yields more substantial improvements across all evaluated properties. Under high-temperature and strong electric field conditions, POSS doping enhances interfacial adhesion and thermal stability, effectively suppressing the cleavage of key chemical bonds, reducing $ \mathrm{CO} $ emissions, and increasing the formation of oxygen-containing intermediates and water molecules, which contributes to improved environmental sustainability.

The crystallization behavior of two commercial polyolefin elastomer (POE) samples was investigated using the fast scanning chip calorimetry (FSC) technique. Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work. Thus, the isothermal crystallization of POE samples was limited to a narrow temperature range. When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization, a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization. This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature. At each crystallization temperature, the lengths of crystallizable segments were different, thus, the low melting peak increased with increasing the crystallization temperature. In terms of the high melting peak attributed to the non-isothermally crystallized crystals, it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature. This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling. The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals, causing the melting peak to shift to the lower temperature.

Polymer optical materials are becoming increasingly important in modern technologies owing to their unique properties. This study applies coupled perturbed density functional theory (DFT) to predict the refractive index (RI) and Abbe number of polymers. Using the Lorentz-Lorenz equation, the frequency-dependent polarizability and molecular volume were calculated to estimate RI. Wavelength-dependent RI values were used to derive the Abbe numbers. Our results show a strong correlation with experimental data, with Pearson coefficients of 0.912 for RI and 0.968 for Abbe number, enabling the introduction of linear correction functions to minimize discrepancies between theoretical predictions and experimental results. By categorizing polymers into classes such as poly(methyl methacrylate) (PMMA)-, polyethylene (PE)-, polycarbonate (PC)-, polyimide (PI)-, and polyurethane (PU)-based materials, this method enables precise predictions and reduces discrepancies using linear correction functions. This efficient and direct computational framework avoids the complexity of traditional models and offers a practical tool for the design and optimization of advanced optical materials.