Hydrogen bonds (H-bonds) are the most essential non-covalent interactions in nature, playing a crucial role in stabilizing the secondary structures of proteins. Taking inspiration from nature, researchers have developed several multiple H-bonds crosslinked supramolecular polymer materials through the incorporation of H-bond side-chain units into the polymer chains. N-acryloyl glycinamide (NAGA) is a monomer with dual amides in the side group, which facilitates the formation of multiple dense intermolecular H-bonds within poly(N-acryloyl glycinamide) (PNAGA), thereby exhibiting diverse properties dependent on concentration and meeting various requirements across different applications. Moreover, numerous attempts have been undertaken to synthesize diverse NAGA-derived units through meticulous chemical structure regulation and fabricate corresponding H-bonding crosslinked supramolecular polymer materials. Despite this, the systematic clarification of the impact of chemical structures of side moieties on intermolecular associations and material performances remains lacking. The present review will focus on the design principle for synthesizing NAGA-derived H-bond side-chain units and provide an overview of the recent advancements in multiple H-bonds crosslinked PNAGA-derived supramolecular polymer materials, which can be categorized into three groups based on the chemical structure of H-bonds units: (1) monomers with solely cooperative H-bonds; (2) monomers with synergistic H-bonds and other physical interactions; and (3) diol chain extenders with cooperative H-bonds. The significance of subtle structural variations in these NAGA-derived units, enabling the fabrication of hydrogen-bonded supramolecular polymer materials with significantly diverse performances, will be emphasized. Moreover, the extensive applications of multiple H-bonds crosslinked supramolecular polymer materials will be elucidated.

Polymer aging under environmental conditions causes deterioration of service properties. Understanding the aging behavior and mechanism is important not only for lifetime prediction, but also for material improvement and development. Therefore, comprehensive characterization of polymer materials during aging is crucial. In this review, various analytical methods for characterization of chemical changes, physical changes and service properties are introduced. Based on that, methods for stabilization evaluation and lifetime prediction, especially sensitive evaluation methods are reviewed. Chemical changes include molecular weight changes by chain scission and crosslinking, functional group changes on the surface and in the bulk, formation of free radicals, formation of small molecular species as the degradation products, and chemical distribution by heterogeneous aging and additives migration. Physical changes include crystallization changes (post- or chemi-crystallization) and morphology changes (cracking, debonding, etc.). Service property changes include deterioration of processability, mechanical properties, electrical properties and appearance. In the end, existing problems and future research perspective are proposed, including relationship between chemical/physical changes and service properties, introduction of modern mathematical and computer tools.

Tumor-associated carbohydrate antigens (TACAs) provide a special class of tumor-specific antigens that show promising applications in cancer immunotherapy. However, the weak immunogenicity and structural complexity of TACAs are obstacles to their clinical application. Here, based on a fast and low-cost purification strategy for oligosaccharide synthesis, the synthesis of tumour-associated carbohydrate antigens Globo H and mannobiose which resembles repeat unit of mannan was achieved. To enhance the immunogenicity and multivalent effect, Globo H and mannobiose were covalently attached to degradable polymer backbones. 2D spindle-like lamellar micelle and globular micelle were obtained from glycopolymer through a solvent-exchange method of self-assembly. The glyconanoparticle showed good biocompatibility and degradability. Immunological functions of these glyconanoparticles such as stimulation of BMDC to cause upregulation of inflammatory factors were preliminarily explored.

The self-consistent field theory (SCFT) was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte (PE) brushes formed by grafting weak PE chains onto the surfaces of two long and parallel columns with rectangular-shaped cross-section immersed in a salty aqueous solution. The dependences of the brush heights and the average degree of ionization on various system parameters were also investigated. When the brush separation is relatively large compared with the unperturbed brush height, the degree of interpenetration between the two opposing PE brushes was found to increase with increasing grafting density and bulk degree of ionization. The degree of interpenetration also increases with the bulk salt concentration in the osmotic brush regime. Numerical results further revealed that, at a brush separation comparable to the unperturbed brush height, the degree of interpenetration does not increase further with increasing bulk degree of ionization, bulk salt concentration in the osmotic regime and grafting density. The saturation of the degree of interpenetration with these system parameters indicates that the grafted PE chains in the gap between the two columns retract and tilt in order to reduce the unfavorable electrostatic and steric repulsions between the two opposing PE brushes. Based on salt ion concentrations at the midpoint between the two opposing brushes, a quantitative criterion in terms of the unperturbed brush height and Debye screening length was established to determine the threshold value of the brush separation beyond which they are truly independent from each other.

Nonconventional luminescent materials (NLMs) are a type of organic luminescent materials that does not contain aromatic units. Due to the simplicity of the synthesis process, mild reaction conditions, good hydrophilicity and biological compatibility, NLMs have attracted much attention. Nevertheless, numerous reports indicate that NLMs can only effectively luminesce at high concentrations and in solid state, which limits their applicability in the field of cell imaging. This study addresses this limitation by designing and synthesizing oligomers P1, P2 and P3 using ethylene glycol diglycidyl ether and amine compounds containing ethylene groups. These oligomers exhibit remarkable luminescence efficiency reaching as high as 9.2% in dilute solutions (0.1 mg/mL), making them among the best NLMs in this category. Furthermore, the synthesized oligomers exhibit excitation wavelength-dependent and concentration-dependent luminescence intensity, fluorescence response to temperature and pH changes, as well as the ability to identify Fe³⁺, Cu²⁺ and Mo⁵⁺ in dilute solutions. These characteristics render them potentially useful in the for cell imaging.

Photodynamic therapy (PDT) has been emerged as a promising modality for cancer treatment. However, the development of drug delivery system enabling continuous release of photosensitizers (PSs) for long-term PDT treatment still remains challenges. Herein, a H₂O₂-responsive injectable hydrogel, covalently crosslinked by N¹-(4-boronobenzyl)-N³-(4-boronophenyl)-N¹,N¹,N³,N³-tetramethylpropane-1,3-diaminium (TSPBA) with PVA containing polythiophene quaternary ammonium salt (PT2) polymer dots (PDots) as a photosensitizer was fabricated. Under the stimulation of H₂O₂, the obtained injectable hydrogel gradually degrades and releases PDots. In vitro experiments suggested that the released PDots could realize efficient tumor cells inhibition through its robust singlet oxygen generation capability upon 577 nm laser irradiation. In vivo studies demonstrated a sustained retention of PDots for at least 7 days following single-dose administration, facilitating efficient tumor inhibition with light treatments for 3 times without apparent biotoxicity. This work presents an innovative polymer dots-based composite local drug delivery system for long-term PDT in cancer treatment.

Polyethyleneimine (PEI), as a widely used polymer material in the field of gene delivery, has been extensively studied for modification and shielding to reduce its cytotoxicity. However, research aimed at preparing degradable PEI is scarce. In this work, the hydrogen peroxide (H₂O₂) oxidation method was used to introduce degradable amide groups in the PEI and a series of oxidized PEI22k (oxPEI22k) with different degrees of oxidation were synthesized by regulating the dosage of H₂O₂. The relationship between the oxidation degree of oxPEI22k and the gene transfection efficiency of oxPEI22k was studied in detail, confirming that the oxPEI22k with oxidation degrees of 16.7% and 28.6% achieved improved transfection efficiency compared to unmodified PEI. These oxPEI22k also proved reduced cytotoxicity and improved degradability. Further, this strategy was extended to the synthesis of low-molecular-weight oxPEI1.8k. The oxPEI1.8k with suitable oxidation degree also achieved improved transfection efficiency and reduced cytotoxicity. In brief, this work provided high-efficiency and low-cytotoxicity degradable gene delivery carriers by regulating the oxidation degree of PEI, which was of great significance for promoting clinical applications of PEI.

Amyloidosis is characterized by the deposition of fibrillar aggregates, with a specific peptide or protein as the primary component, in affected tissues or organs. Excessive proliferation and deposition of amyloid fibrils can cause organismal dysfunction and lethal pathological outcomes associated with amyloidosis. In this study, a nanochaperone (nChap-NA) was developed to inhibit protein misfolding and fibrillation by simulating the function of natural molecular chaperones. The nanochaperone was prepared by self-assembly of two block copolymers PEG-b-PCL and PCL-b-P(NIPAM-co-AANTA), which had a phase-separated surface consisting of hydrophobic PNIPAM microdomains with coordinative NTA(Zn) moieties and hydrophilic PEG chains. The hydrophobic interaction of the PNIPAM microdomain and the coordination of NTA(Zn) synergistically work together to effectively trap the amyloid monomer and block its fibrillation site. Insulin and human islet amyloid polypeptide (hIAPP) were used as model proteins to investigate the nanochaperone's inhibition of amyloid misfolding and fibrillation. It was proved that the nanochaperone could stabilize the natural conformation of the trapped insulin and hIAPP, and effectively inhibit their fibrillation. In vivo study demonstrated that the nanochaperone could effectively preserve the bioactivity of insulin and reduce the cytotoxicity caused by hIAPP aggregation. This study may provide a promising strategy for the prophylactic treatment of amyloidosis.

Silicon-containing arylacetylene (PSA) resins have broad application prospects because of their excellent heat resistance. However, improving their mechanical properties and interfacial bonding with reinforcement fibers while maintaining heat resistance is a challenge in engineering applications. Here, poly(diethynylbenzene-methylsilyl-3-benzonitrile) (DEB-CN) and poly(diethynylbenzene-methylsilyl-3,6-diethynylcarbazole-3-benzonitrile) (DEC-CN) were synthesized via an isopropylmagnesium chloride lithium-chloride complex (i-PrMgCl·LiCl), overcoming the compatibility problem between cyano groups and Grignard reagents. The cyano and alkyne groups in the resin underwent cyclization to form pyridine, catalyzed by the -NH- moiety in DEC-CN, resulting in extremely high thermal stability (5% weight loss temperature: 669.3 °C, glass transition temperature >650 °C). The combination of cyano dipole-dipole pairing and hydrogen bonding greatly enhanced the resin-fiber interface properties, while the generated pyridine promoted stress relief in the crosslinked network, substantially improving the mechanical properties of the cyano-silicon-containing arylacetylene resin composites. The flexural strength of quartz fiber cloth/DEC-CN composites was 298.2 MPa at room temperature and 145.9 MPa at 500 °C, corresponding to 84.0% and 127.6% enhancements, respectively, over the cyano-free counterpart. These cyano-silicon-containing arylacetylene resins exhibited a dual reinforcement mechanism involving physical interfacial interactions and chemical crosslinking, achieving a good balance between thermal stability and mechanical properties.

Nuclear magnetic resonance (NMR) is an advanced technique for the molecular weight (MW) determination of polymers at quantitative conditions. In this study, we investigate the effect of liquid ¹H-NMR instrumental setting parameters on the MW determination of polyether diols, namely poly(ethylene glycol) (PEG) and poly(tetramethylene oxide) (PTMO) diols, using hydroxymethylene groups as chain-ends. Our results show that the protons in chain-ends have larger spin-lattice relaxation time (T₁) than those in main chains. To let most of the excited protons relax to the equilibrium state, the delay time (d₁) should be much larger than T₁ of end-groups. When ¹³C decoupling is inactive, the relative errors can be greater than 60%, due to the ¹³C-coupled proton satellite peaks, which can overlap with chain-end groups or be misassigned as chain-ends. The optimal quantitative NMR conditions for the MW estimation of polyethers are revealed below: standard pulse with inverted gated ¹³C decoupling pulse sequence, 32 scans, 2.0 s acquisition time in 90 degree of flip angle and 30 s d₁. The MWs determined from ¹H quantitative NMR are all smaller than those from SEC which are relative to polystyrene (PS) standards, since the size of polyether chains is larger than that of PS with the same MW. In addition, the MW obtained from SEC for PTMOs shows larger overestimation than PEGs, suggesting PEG chains are more flexible than PTMO’s.

Owing to the significant increase in air pollutants and the spread of infectious diseases, it seems that the use of face masks will become an essential item in human societies. Therefore, there is a need to conduct more research to develop novel types of respirators utilizing up-to-date science such as nanotechnology. In this study, we fabricated a nanocomposite fibrous filter containing modified graphene oxide (GO) and zinc oxide (ZnO) nanoparticles. This layer was used as an active filter for absorbing and removing air pollutants, such as suspended sub-micron particles (below 2.5 microns) and CO₂, NO₂, and SO₂ gases. The synthesized nanostructures and fibrous filters were characterized by different analysis (FTIR, XRD, TGA, and FESEM), and the performance of the filters was surveyed by tests such as pressure drop, CO₂, NO₂, SO₂ gas rejection, and particulate removal. The results showed that the stabilization of the modified GO and ZnO nanostructures on the fibrous filter improved the effectiveness of this filter as a mask for removing toxic particles and gases, and the filter containing nanoparticles had the best performance.

As a type of bi-functional device, electrochromic supercapacitors (EC-SCs) have attracted extensive attention in diverse applications such as flexible electronics. However, despite recent encouraging progress, rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical applications. Here, we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of 3-fluorothiophene. The electrosynthesized free-standing poly(3-fluorothiophene) (PFT) films simultaneously achieve high electrochromic performance (optical contrast 42% at 560 nm with reversible color changes between purple and blue), and good capacitance property (290 F·g⁻¹, 1 A·g⁻¹), as well as outstanding cyclic stability (<2% reduction after 20000 cycles). We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices (FESDs), and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like bending. Such a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.

To realize single-stimulus-induced simultaneous multi-behaviors in hydrogels is still quite challenging nowadays. Herein, an intelligent pH-responsive hydrogel (BP4VA/PAS) with rapid and high contrast changes in color, fluorescence, and shape simultaneously is reported. The BP4VA/PAS hydrogel is fabricated by incorporating styryl anthracene derivative (BP4VA) into copolymer networks (PAS) of acrylamide and sodium 4-styrene sulfonate. Under acid conditions, the protonation of BP4VA generates a rapid change with high color contrast from yellow to red and a fluorescence switch between bright green and weak red emission. At the same time, the electrostatic interactions between 2H-BP4VA²⁺ and sulfonate anions suspended on PAS trigger BP4VA/PAS hydrogels to shrink. Upon alkaline treatment, the 2H-BP4VA²⁺/PAS hydrogel deprotonates and recovers to its original color, fluorescence, and shape. Furthermore, utilizing rapid and remarkable pH-responsive properties of BP4VA/PAS hydrogels, we successfully demonstrated its applications in biomimicry, camouflage, and multistage information encryption. Collectively, this work provided an elegant strategy to develop intelligent hydrogels in applications of biomimetic smart materials and information encryption.

Electrospun nanofibrous separators, despite lacking superior mechanical strength, have gained widespread attention with high porosity and facile processing. Herein, utilizing the fact that thermal imidization temperature of poly(amic acid) (PAA) into polyimide (PI) coincides with the pre-oxidation temperature of polyacrylonitrile (PAN) into carbon fiber, we proposed a new cross-electrospinning strategy to obtain a composite nanofibrous separator (PI/oPAN) randomly interwoven by PI and pre-oxidized PAN (oPAN) nanofibers, via synchronously electrospinning the PAA and PAN onto the same collector and then heat-treating for 2 h at 300 °C. The resultant PI/oPAN separator was able to preserve high porosity (71.7%), electrolyte wettability and thermal stability of PI nanofibrous membrane, and surprisingly exhibited high mechanical strength, being 3 times of PI, which mainly because of the numerous adhesion points generated by the melting of PAN in the pre-oxidation process. Meanwhile, the polar groups of oPAN and 3D fibrous network enhanced the PI/oPAN separator’s ionic conductivity and Li⁺ transference number, rendering the corresponding cell with more stable cycling performance than cells assembled with pure PI, PAN or commercial PP separator. Therefore, this work might provide a new avenue for the ongoing design and further development of LIB separators capable of high safety and high performance.

The crystallization behavior of silica-filled polydimethylsiloxane (PDMS) was investigated in detail by ¹H solid-state nuclear magnetic resonance (¹H SS-NMR) in combination with synchrotron radiation wide-angle X-ray scattering (WAXS), and temperature-modulated differential scanning calorimetry (TMDSC) techniques. For neat PDMS, no apparent difference is observed for the crystallinity characterized by ¹H SS-NMR and WAXS at low-temperature regions. However, upon filler addition, a 15%−35% lower difference in crystallinity is observed measured by ¹H SS-NMR compared to WAXS. The origin of such mismatch was explored through multi-component structural, dynamics, and chain-order analysis of PDMS samples with different filler fractions. The 1D integrated WAXS results of PDMS with different filler fractions at different temperatures show that the packing structure as well as crystal size basically remain unchanged, but as the filler fraction increases from 0 phr to 60 phr, the rigid component’s dynamics order parameter S_r obtained by ¹H SS-NMR decreases from 0.70 to 0.55. The filler fraction-dependent crystallinity calculated based on S_r was compared with experimental values, revealing a behavior of decreasing order in the crystalline region. Combining with the results of accelerated chain dynamics in crystalline region as reflected by T₂ values, the molecular origin is attributed to the formation of CONDIS crystals, whose conformational order is lost but the position and orientation orders are kept. Such hypothesis is further supported by the TMDSC results, where, as the filler fraction increases from 0 phr to 60 phr, the melting range widens from 8.77 K to 14.56 K, representing a growth of 166%. In addition to previous reports related to the condition for forming CONDIS mesophase, i.e., temperature, pressure, and stretching, the nano-sized filler could also introduce the local conformational disorder for chain packing.

Nowadays organosilicon luminescent materials are of increasing interest due to the variety of their synthetic or modification techniques and application fields. Ladder polyphenylsilsesquioxanes (L-PPSQ) are a unique class of organosilicon polymers, which can be ideal matrices for the luminescent composites due to their high thermal stability, optical transparency and mechanical strength. In this work, new mechanically strong, heat-resistant, transparent and sensitive to ammonia vapor luminescent composite films based on L-PPSQ have been obtained. As the source of Europium ions oligophenyleuropiumsiloxane was used, demonstrating perfect compatibility to the matrix due to the similar nature. To improve luminescent properties of the films, new organosilicon ligands were introduced into the composites and their influence on the properties of the materials was studied. Valuable properties of described composites may allow their further application as multifunctional coatings.

The effect of temperature on the electrical conductivity (σ) and Seebeck coefficient (S) of n-type vapor grown carbon nanofibers (CNFs) and poly(vinylidene fluoride) (PVDF) melt-mixed with 15 wt% of those CNFs is analyzed. At 40 °C, the CNFs show stable n-type character (S=−4.8 μV·K⁻¹) with an σ of ca.165 S·m⁻¹, while the PVDF/CNF composite film shows an σ of ca. 9 S·m⁻¹ and near-zero S (S=−0.5 μV·K⁻¹). This experimental reduction in S is studied by the density functional tight binding (DFTB) method revealing a contact electron transfer from the CNFs to the PVDF in the interface. Moreover, in the temperature range from 40 °C to 100 °C, the σ(T) of the CNFs and PVDF/CNF film, successfully described by the 3D variable range hopping (VRH) model, is explained as consequence of a thermally activated backscattering mechanism. On the contrary, the S(T) from 40 °C to 100 °C of the PVDF/CNF film, which satisfactorily matches the model proposed for some multi-walled carbon nanotube (MWCNT) doped mats; however, it does not follow the increase in S(T) found for CNFs. All these findings are presented with the aim of discerning the role of these n-type vapor grown carbon nanofibers on the σ and S of their melt-mixed polymer composites.

This study utilizes molecular dynamics simulation to investigate the complex dynamics of entangled semi-flexible polymer melts. The investigation reveals a significant stress overshoot phenomenon in the systems, demonstrating the intricate interplay between shear rates, chain orientation, and chain stretching dynamics. Additionally, the identification of metastable states, characterized by a dual-plateau phenomenon in the shear stress-strain curve at specific Rouse-Weissenberg number Wi_R, showcases the system’s responsiveness to external perturbations and its transition to stable shear banding states. Moreover, the analysis of flow field deviations uncovers a progression of shear bands with increasing Wi_R, displaying distinct behaviors in the system’s dynamics under different shear rates and chain lengths. These findings challenge established theoretical frameworks and advocate for refined modelling approaches in polymer rheology research.

Polyimide (PI) is widely used in high-frequency communication technology due to its exceptional comprehensive properties. However, traditional PI has a relatively elevated dielectric constant and dielectric loss. Herein, the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films. In comparison to the dielectric constant of 2.9 of neat PI, PI with an interchain cross-linking structure containing 2 wt% 1,3,5-tris(4-aminophenyl)benzene (TAPB) (interchain-PI-2) exhibited the reduced dielectric constant of 2.55 at 1 MHz. The PI films with intrachain cross-linking structure containing 2 wt% TAPB (intrachain-PI-2) exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of 0.0075 at 1 MHz. It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport. The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced. Moreover, in contrast to interchain-PI films, the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased. This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.

Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry. A sulfur-based lightly crosslinker can potentially enhance the self-healing capabilities of rubber. Moreover, the rubber composites were studied for non-covalent interactions between the benzene rings of SBR and CB. In this research, rubber samples were prepared, and their structure was investigated using Fourier transform infrared (FTIR), and Raman spectroscopy. The red shift in Raman spectroscopy confirmed non-covalent interaction or hydrophobic interaction between SBR and CB in NR/SBR composites exposed to CB due to environmental change. The differential scanning calorimetry (DSC) thermograms showed that NR and SBR were incompatible. Additionally, the mechanical properties of these rubber blends were enhanced as the proportion of NR increased. The maximum self-healing performance reached 40% for the formulation containing 25 phr NR and 75 phr SBR, which also saved energy with low chain end movements. Therefore, these composites could be utilized as a semi-empirical model for studying crosslinked rubber blends, specifically in the rubber tire industry.

Epoxy resins are cross-linked polymeric materials with typically low thermal conductivity. Currently, the introduction of rigid groups into epoxy resins is the main method to improve their intrinsic thermal conductivity. The researchers explored the relationship between the flexible chains of epoxy monomers and the thermal conductivity of the modified epoxy resins (MEP). The effect of flexible chain length on the introduction of rigid groups into the cross-linked structure of epoxy is worth investigating, which is of great significance for the improvement of thermal conductivity of polymers and related theories. We prepared a small molecule liquid crystal (SMLC) containing a long flexible chain via a simple synthesis reaction, and introduced rigid mesocrystalline units into the epoxy resin via a curing reaction. During high-temperature curing, the introduced mesocrystalline units underwent orientational stacking and were immobilized within the polymer. XRD and TGA tests showed that the ordering within the modified epoxy resin was increased, which improved the thermal conductivity of the epoxy resin. Crucially, during the above process, the flexible chains of SMLC provide space for the biphenyl groups to align and therefore affect the thermal conductivity of the MEP. Specifically, the MEP-VI cured with SMLC-VI containing six carbon atoms in the flexible chain has the highest thermal conductivity of 0.40 W·m⁻¹·K⁻¹, which is 125% of the thermal conductivity of SMLC-IV of 0.32 W·m⁻¹·K⁻¹, 111% of the thermal conductivity of SMLC-VIII of 0.36 W·m⁻¹·K⁻¹, and 182% of the thermal conductivity of pure epoxy of 0.22 W·m⁻¹·K⁻¹. The introduction of appropriate length flexible chains for SMLC promotes the stacking of rigid groups within the resin while reducing the occurrence of chain folding. This study will provide new ideas for the enhancement of thermal conductivity of cross-linked polymeric materials.