Alkyl Chain Length Research Articles

Ionic liquid with hydrogen bonding reducing leakage charge for enhancing triboelectric performance

Refining the dielectric layer of a triboelectric nanogenerator (TENG) has been shown to maximize its output performance. Among the available strategies, utilizing an ionic dielectric can improve the output performance notably through the internal formation of an electrical double layer (EDL). However, ions dispersed in the ionic dielectric inevitably cause leakage charge between the surface charged layer and electrode of the ionic dielectric; this reduces the charge density, directly affecting output performance. Here, we investigate optimization of the ionic dielectric of a TENG using various ionic liquids (ILs), with the alkyl chain lengths of the cations and fluoride of anions with different size, to achieve power enhancement based on the EDL effect while concurrently suppressing leakage charge via hydrogen bonding. To elucidate the power enhancement working mechanisms within the ionic dielectric, we characterize the chemical, mechanical, and electrochemical properties of the ionic dielectric, including formation of hydrogen bonds, ionic conductivity, and dielectric constant. These parameters are investigated by varying the ion types, molecular sizes, and concentrations of the ILs within the ionic dielectric. As a results, our findings reveal that an IL of OMIM+PF6- dissolved in a base material of thermoplastic polyurethane (TPU) significantly enhances the voltage and current by 2.3 and 2.9 times, respectively, compared to those of a conventional TENG with TPU. These findings are expected to be implemented across a wide range of TENGs, paving the path for their advanced applications in next-generation energy harvesting.

Dispersion-driven cooperativity in alkyl perylenediimide oligomers: insights from densityfunctional theory.

The cooperative mechanism is of paramount importance in the synthesis of supramolecular polymers with desired characteristics, including molecular mass, polydispersity, and morphology. It is primarily driven by the presence of intermolecular interactions, which encompass strong hydrogen bonding, metal-ligand interactions, and dipole-dipole interactions. In this study, we utilize density functional theory and energy decomposition analysis to investigate the cooperative behavior of perylene diimide (PDI) oligomers with alkyl chains at their imide positions, which lack the previously mentioned interactions. Our systematic examination reveals that dispersion interactions originating from the alkyl side-chain substituents play an important role in promoting cooperativity within these PDIs. This influence becomes even more pronounced for alkyl chain lengths beyond hexyl groups. The energy decomposition analysis reveals that the delicate balance between dispersion energy and Pauli repulsion energy is the key driver of cooperative behavior in PDIs. Additionally, we have developed a mathematical model capable of predicting the saturated binding energies for PDI oligomers of varying sizes and alkyl chain lengths. Overall, our findings emphasize the previously undervalued significance of dispersion forces in cooperative supramolecular polymerization, enhancing our overall understanding of the cooperative mechanism.

Enhanced Efficiency and Stability of Wide‐Bandgap Perovskites via Br‐Rich Bulk and Surface 2D Passivation for Indoor Photovoltaics

Indoor photovoltaics (IPV) is a promising technology to power the rapidly developing Internet of Things (IoT) devices, offering advantages of distributed power source and reduced maintenance cost. Wide‐bandgap perovskite solar cells (PSCs), with the features of easy bandgap tuning and low‐cost solution process, hold significant potential for powering indoor IoT devices. However, the efficiency and stability of wide‐bandgap PSCs suffers from severe phase segregation and surface defects. Here we introduce a novel bromide‐rich 2D passivation strategy targeting both bulk and surface passivation of wide‐bandgap PSCs for IPV application. Ammonium salts with optimized alkyl chain length is confirmed to suppress the phase segregation in the bulk. Bromide‐rich 2D perovskite exhibit superior performance compared to their iodide counterparts, effectively suppressing nonradiative recombination and forming favourable energy band alignment with the ETL. The wide‐bandgap PSCs achieved an impressive PCE up to 41.58% under 1000 lux LED illumination. Furthermore, the wide‐bandgap perovskite module efficiently powers a Bluetooth IoT sensor at 400 lux indoor illumination, which can sense and broadcast the environmental information. This work highlights the remarkable potential of wide‐bandgap PSCs for indoor IoT devices and provides valuable insights into enhancing the efficiency and stability of PSCs for future IoT applications.This article is protected by copyright. All rights reserved.

Synthesis, Stability, Meisenheimer Complex Formation, and Charge‐Transfer Properties of Ultra‐Electron‐Deficient Tetracyano‐Naphthalene Diimides

Tetra‐cyano substituted naphthalene diimides (TCNDIs) with calculated LUMO of ‐5.2 eV, form one of the strongest electron‐acceptors known to date. However, the synthesis and isolation of this class of molecules remain challenging due to its reactivity emanating from its ultra‐electron‐deficiency. Herein we have established an improved synthetic methodology of TCNDIs with cost‐effective reagents and circumventing metallic catalysts. The synthesis is amenable to TCNDIs with the shortest axial alkyl groups, i.e., methyl group and also longer alkyl chains. We also gained insight on how axial alkyl chain lengths influence electron‐deficiency, Meisenheimer complex formation, reactivity, and charge‐transfer of TCNDIs from computation, spectroscopy, and electrochemical studies. The TCNDIs with Me/Et axial groups were found to be more susceptible to moist solvents vis‐à‐vis the TCNDIs with longer alkyl groups. The single crystal structures of the TCNDIs show infinitely π‐stacked structure, and a new C=O···C≡N or C≡N···π motif is discerned. Finally, toluene‐mediated charge‐transfer properties of TCNDIs in the single crystals as well as in solution have been examined.

Dynamics of collisions and uptake of alcohol molecules with hydrated nitric acid clusters.

We investigate the collisions of different alcohol molecules with hydrated nitric acid clusters using a molecular beam experiment and molecular dynamics simulations. The uptake cross sections σp for the molecules evaluated from the experiment are in excellent agreement with the simulations. This suggests that (i) the nontrivial assumptions implemented in the evaluation procedure of the experimental data are valid, and (ii) the simulations describe correctly the major processes in the molecule-cluster collisions. We observe that σp decreases with the increasing alkyl chain length of the alcohol, and also with the branching of the molecules that have the same mass but different structures. These systematic trends can be rationalized based on the accessibility of the hydrophilic OH group, which decreases with the increasing chain length and steric hindrance. The observed trends and their interpretation differ significantly from the simple model of hard-sphere collisions. The obtained data shall be beneficial not only for the fundamental understanding of the molecule-cluster collisions, but also in the modelling of atmospheric new-particle formation and aerosol growth.

Sugar-Based Surfactants: Effects of Structural Features on the Physicochemical Properties of Sugar Esters and Their Comparison to Commercial Octyl Glycosides.

Two series of sugar esters with alkyl chain lengths varying from 5 to 12 carbon atoms, and with a head group consisting of glucose or galactose moieties, were synthesized. Equilibrium surface tension isotherms were measured, yielding critical micellar concentration (CMC) surface tensions at CMC (γcmc) and minimum areas at the air-water interface (Amin). In addition, Krafft temperatures (Tks) were measured to characterize the ability of molecules to dissolve in water, which is essential in numerous applications. As a comparison to widely used commercial sugar-based surfactants, those measurements were also carried out for four octyl d-glycosides. Impacts of the linkages between polar and lipophilic moieties, alkyl chain lengths, and the nature of the sugar head group on the measured properties were highlighted. Higher Tk and, thus, lower dissolution ability, were found for methyl 6-O-acyl-d-glucopyranosides. CMC and γcmc decreased with the alkyl chain lengths in both cases, but Amin did not appear to be influenced. Both γcmc and Amin appeared independent of the ester group orientation. Notably, alkyl (methyl α-d-glucopyranosid)uronates were found to result in noticeably lower CMC, possibly due to a closer distance between the carbonyl function and the head group.

Cellulose gelation in aqueous hydroxide solutions by CO2(g): Fact and theory

Understanding how the solvent structure affects the stability of the dissolved state and the following precipitation is important for designing future dissolution-coagulation systems for cellulose processing. In this study, two morpholinium hydroxides with different alkyl chain lengths, namely N,N-dimethylmorpholinium hydroxide (NDMMOH(aq)) and N‑butyl‑N-methyl morpholinium hydroxide (BMMorOH(aq)), were studied and compared with the previously thoroughly investigated cellulose solvent benzyltriemethylammonium hydroxide (Triton B(aq)) which is well-known for its superior ability to stabilize the dissolved state. Cellulose solutions in each solvent were characterized by NMR, flow and frequency sweeps, while cellulose coagulation by CO2(g) was followed by in situ FTIR, pH and temperature measurements. The coagulated systems were characterized by CP/MAS 13C NMR, flow, and frequency sweep measurements. Complementary molecular dynamic (MD) simulations were performed to gain a deeper insight into the observed gelation behavior. The intrinsic viscosity indicated more extended cellulose chains in the solvents with more hydrophobic moieties (Triton B and BMMorOH). Even though the course of coagulation did not show any significant differences during monitoring, both the properties of the obtained gels and the MD simulations indicated differences in formation and properties of the coagulated materials that could be related both to the choice of solvent and coagulant.

A Pseudo-Surfactant Chemical Permeation Enhancer to Treat Otitis Media via Sustained Transtympanic Delivery of Antibiotics.

Chemical permeation enhancers (CPEs) represent a prevalent and safe strategy to enable noninvasive drug delivery across skin-like biological barriers such as the tympanic membrane (TM). While most existing CPEs interact strongly with the lipid bilayers in the stratum corneum to create defects as diffusion paths, their interactions with the delivery system, such as polymers forming a hydrogel, can compromise gelation, formulation stability, and drug diffusion. To overcome thischallenge, differing interactions between CPEs and the hydrogel system are explored, especially those with sodium dodecyl sulfate (SDS), an ionic surfactant and a common CPE, and those with methyl laurate (ML), a nonionic counterpart with a similar length alkyl chain. Notably, the use of ML effectively decouples permeation enhancement from gelation, enabling sustained delivery across TMs to treat acute otitis media (AOM),which is not possible with the use of SDS. Ciprofloxacin and ML are shown to form a pseudo-surfactant that significantly boosts transtympanic permeation. The middle ear ciprofloxacin concentration is increased by 70-fold in vivo in a chinchilla AOM model, yielding superior efficacy and biocompatibility than the previous highest-performing formulation. Beyond improved efficacy and biocompatibility, this single-CPE formulation significantly accelerates its progression toward clinical deployment.

Synthesis, Characterisation, and In Vitro Evaluation of Biocompatibility, Antibacterial and Antitumor Activity of Imidazolium Ionic Liquids.

In recent decades, ionic liquids (ILs) have garnered research interest for their noteworthy properties, such as thermal stability, low or no flammability, and negligible vapour pressure. Moreover, their tunability offers limitless opportunities to design ILs with properties suitable for applications in many industrial fields. This study aims to synthetise two series of methylimidazolium ILs bearing long alkyl chain in their cations (C9, C10, C12, C14, C16, C18, C20) and with tetrafluoroborate (BF4) and the 1,3-dimethyl-5-sulfoisophthalate (DMSIP) as counter ions. The ILs were characterised using 1H-NMR and MALDI-TOF, and their thermal behaviour was investigated through DSC and TGA. Additionally, the antimicrobial, anticancer, and cytotoxic activities of the ILs were analysed. Moreover, the most promising ILs were incorporated at different concentrations (0.5, 1, 5 wt%) into polyvinyl chloride (PVC) by solvent casting to obtain antimicrobial blend films. The thermal properties and stability of the resulting PVC/IL films, along with their hydrophobicity/hydrophilicity, IL surface distribution, and release, were studied using DSC and TGA, contact angle (CA), SEM, and UV-vis spectrometry, respectively. Furthermore, the antimicrobial and cytotoxic properties of blends were analysed. The in vitro results demonstrated that the antimicrobial and antitumor activities of pure ILs against t Listeria monocytogenes, Escherichia coli, Pseudomonas fluorescens strains, and the breast cancer cell line (MCF7), respectively, were mainly dependent on their structure. These activities were higher in the series containing the BF4 anion and increased with the increase in the methylimidazolium cation alkyl chain length. However, the elongation of the alkyl chain beyond C16 induced a decrease in antimicrobial activity, indicating a cut-off effect. A similar trend was also observed in terms of in vitro biocompatibility. The loading of both the series of ILs into the PVC matrix did not affect the thermal stability of PVC blend films. However, their Tonset decreased with increased IL concentration and alkyl chain length. Similarly, both the series of PVC/IL films became more hydrophilic with increasing IL concentration and alkyl chain. The loading of ILs at 5% concentration led to considerable IL accumulation on the blend film surfaces (as observed in SEM images) and, subsequently, their higher release. The biocompatibility assessment with healthy human dermal fibroblast (HDF) cells and the investigation of antitumoral properties unveiled promising pharmacological characteristics. These findings provide strong support for the potential utilisation of ILs in biomedical applications, especially in the context of cancer therapy and as antibacterial agents to address the challenge of antibiotic resistance. Furthermore, the unique properties of the PVC/IL films make them versatile materials for advancing healthcare technologies, from drug delivery to tissue engineering and antimicrobial coatings to diagnostic devices.

Alkyl chain length affecting the structure and interactions of choline-based amino acid ionic liquids: Insights from a computational study

The influences of the alkyl chain length of amino acid anions on the structure and interactions of choline-based amino acid ([Cho][AA]) ionic liquids were investigated based on density functional theory (DFT) and molecular dynamics (MD) simulations. The most stable configuration of the individual [Cho][AA] ion pair was determined, revealing negligible variations in the binding energy between choline cation ([Cho]+) and different amino acid anions ([AA]−). To further characterize the intermolecular interactions between charged entities, the atoms in molecules theory (AIM) and independent gradient model based on Hirshfeld partition (IGMH) were employed, which highlight the presence of robust hydrogen bonds between [Cho]+ and [AA] −, underscoring their significance in shaping the structure of [Cho][AA] ion pairs. The MD studies exhibited the aggregation of anions in [Cho][AA] ILs, which was attributed to side chain interactions of anions. This aggregation effect becomes more pronounced with the elongation of anionic alkyl chain. Simultaneously, radial distribution functions (RDF) analysis revealed a higher probability of hydrogen bonds occurring between [Cho]+ and [AA]− as the alkyl chain in [AA]− lengthened. Additionally, the hydrogen bond lifetimes roughly display an increasing trend as the alkyl chain of the [AA]− increases, which may be due to the reduced diffusion coefficients of ions. Hopefully, our results would contribute fundamental knowledge regarding the impact of alkyl chain length of anions on the structure and interactions in the choline-based amino acid ionic liquids.

Epoxy Resins with Controllable "Thermally Conductive-Self-Healing" Synergies: a New Material to Meet the Needs of Flexible Electronic Devices.

With the popularization of 5G technology and artificial intelligence, thermally conductive epoxies with self-healing ability will be widely used in flexible electronic materials. Although many compounds containing both performances have been synthesized, there is little systematic theory to explain this coordination mechanism. In this paper, alkyl chains of different lengths were introduced to epoxies for discussing the thermally conductive, the self-healing performance, and the synergistic effect. A series of electronic-grade biphenyl epoxies (4,4'-bis(oxiran-2-ylmethoxy)-1,1'-biphenyl (1), 4,4'-bis(2-(oxiran-2-yl)ethoxy)-1,1'-biphenyl (2), 4,4'-bis(3-(oxiran-2-yl)propoxy)-1,1'-biphenyl (3), and 4,4'-bis(4-(oxiran-2-yl)butoxy)-1,1'-biphenyl (4) were synthesized and characterized. Furthermore, they were cured with decanedioic acid to produce polymers. Results showed that alkyl chains can both affect the two properties, and the epoxies suitable for specific application scenarios can be prepared by adjusting the length of alkyl chains. In terms of thermal conductivity, compound 1 was a most promising material. However, compound 4 was expected to be utilized in flexible electronic devices because of its acceptable thermal conductivity, self-healing ability, transparency, and flexibility.

N-Hydroxyalkanamide Based Organo/hydrogels as Novel Scaffolds for pH-Dependent Metronidazole and Theophylline Release.

The traditional delivery of metronidazole and theophylline presents challenges like bitter taste, variable absorption, and side effects. However, gel-based systems offer advantages including enhanced targeted drug delivery, minimized side effects, and improved patient compliance, effectively addressing these challenges. Consequently, a cost-effective synthesis of N-hydroxyalkanamide gelators with varying alkyl chain lengths was achieved in a single-step reaction procedure. These gelators formed self-assembled aggregates in DMSO/water solvent system, resulting in organo/hydrogels at a minimum gelation concentration of 1.5% w/v. Subsequently, metronidazole and theophylline were encapsulated within the gel core and released through gel-to-sol transition triggered by pH variation at 37 °C, while maintaining the structural-activity relationship. UV-vis spectroscopy was employed to observe the drug release behavior. Furthermore, in vitro cytotoxicity assays revealed cytotoxic effects against A549 lung adenocarcinoma cells, indicating anti-proliferative activity against human lung cancer cells. Specifically, the gel containing theophylline (16HAD+Th) exhibited cytotoxicity on cancerous A549 cells with IC50 values of 19.23 ± 0.6 µg/mL, followed by the gel containing metronidazole (16HAD+Mz) with IC50 values of 23.75 ± 0.7 µg/mL. Moreover, the system demonstrated comparable antibacterial activity against both gram-negative (E. coli) and gram-positive bacteria (S. aureus).

The effect of polymer with tunable alkyl spacers on the microstructure of amphoteric membrane for vanadium redox flow battery (VRB)

Amphoteric membranes, as promising candidates for VRBs, have attracted more attention. The side-chain-type polymers go far towards improving ion exchange capacity and further enhancing ion conductivity. A kind of Amphoteric ion exchange membranes (AIEMs) with different alkyl chain lengths (C2, C6, and C12 spacers) were synthesized by using ring-opening metathesis polymerization (ROMP). In addition, the interactions between N-containing groups with positively charged and -SO3- groups prevent swelling and vanadium crossover. The microphase separation structure through side chain induction was regulated, to respond to the ionic mobility of the membrane. The effect of the spacer lengths on the ion selectivity of AIEMs is investigated. In addition, the size and matrix of the constructed ion channel were calculated by using coarse-grained molecular dynamics (CGMD) simulation, which further verified the experiment.

Synthesis and Properties of Photocurable Polymers Derived from the Polyesters of Glycerol and Aliphatic Dicarboxylic Acids.

The rapid development of 3D printing technology and the emerging applications of shape memory elastomer have greatly stimulated the research of photocurable polymers. In this work, glycerol (Gly) was polycondensed with sebacic, dodecanedioic, or tetradecanedioic acids to provide precursor polyesters with hydroxyl or carboxyl terminal groups, which were further chemically functionalized by acryloyl chloride to introduce sufficient, photocurable, and unsaturated double bonds. The chemical structures of the acrylated polyesters were characterized by FT IR and NMR spectroscopies. The photoinitiated crosslinking behavior of the acrylated polyesters under ultraviolet irradiation without the addition of any photoinitiator was investigated. The results showed that the precursor polyesters that had a greater number of terminated hydroxyls and a less branched structure obtained a relatively high acetylation degree. A longer chain of aliphatic dicarboxylic acids (ADCAs) and higher ADCA proportion lead to a relatively lower photopolymerization rate of acrylated polyesters. However, the photocured elastomers with a higher ADCA proportion or longer-chain ADCAs resulted in better mechanical properties and a lower degradation rate. The glass transition temperature (Tg) of the elastomer increased with the alkyl chain length of the ADCAs, and a higher Gly proportion resulted in a lower Tg of the elastomer due to its higher crosslinking density. Thermal gravimetric analysis (TGA) showed that the chain length of the ADCAs and the molar ratio of Gly to ADCAs had less of an effect on the thermal stability of the elastomer. As the physicochemical properties can be adjusted by choosing the alkyl chain length of the ADCAs, as well as changing the ratio of Gly:ADCA, the photocurable polyesters are expected to be applied in multiple fields.

Effect of charge on the rotation of prolate nitroxide spin probes in room-temperature ionic liquids

We have studied the rotational diffusion of two prolate nitroxide probes, the doubly negatively charged peroxylamine disulfonate (Frémy's salt − FS) and neutral di-tert-butyl nitroxide (DTBN), in a series of 1-alkyl-3-methylimidazolium tetrafluoroborate room-temperature ionic liquids (RTILs) having alkyl chain lengths from two to eight carbons using electron paramagnetic resonance (EPR) spectroscopy. Though the size and shape of the probes are reasonably similar, they behave differently due to the charge difference. The rotation of FS is anisotropic, and the rotational anisotropy increases with the alkyl chain length of the cation, while the rotation of DTBN is isotropic. The hyperfine coupling constant of DTBN decreases as a function of the alkyl chain length and is proportional to the relative permittivity of ionic liquids. On the other hand, the hyperfine coupling constant of FS increases with increasing chain length. These behaviors indicate the location of each probe in RTILs. FS is likely located in the polar region near the network of charged imidazolium ions. DTBN molecules are predominately distributed in the nonpolar domains.

Improving the performance parameters of organic field-effect transistors via alkyl chain length of boronic acid self-assembled monolayers

Interface modification is a promising technique for enhancing electrical parameters of Organic Field Effect Transistor (OFETs). In OFETs, self-assembled monolayer molecules are widely used for treatment dielectric/semiconductor interface layer. Modification of dielectric/semiconductor layer with SAM molecules ensures a variety of potential applications. Boronic acids with four different alkyl chain lengths (Cn-BA; n = 8, 10, 12, 14) molecules were used in this study to treat the Al2O3 dielectric surface in dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) based OFETs. Treated with SAMs improve the mobility of Al2O3 surfaces for linear and saturation regime and threshold voltages shifted from positive direction. The morphological and electrical characterizations were performed for fabricated OFET. The results show that alkyl-boronic acids SAM molecules open a new perspective for further optoelectronic applications due to its application for oxide surfaces and controllability.

Newly synthesized surfactants as antimicrobial and anti-adhesion agents

Quaternary ammonium salts (QAS) are widely used in medicine, industry and agriculture as disinfectants, biocides, and fungicides. QAS have the ability to coat various surfaces, prevent adhesion of microorganisms to them and inhibit the formation of biofilm. A group of surfactants derived from benzoic acid with different chemical structures was tested: monomeric QAS with different alkyl chain lengths (C12, C14, C16), gemini QAS containing 12-carbon alkyl chains and linkers of various lengths (3,4,6 methylene groups), as well as multifunctional QAS. Among the tested surfactants, monomeric QAS showed the highest bactericidal and fungicidal activity. All three groups of tested compounds inhibited the filamentation of C. albicans. The best antimicrobial activity was demonstrated by the monomeric surfactant C12AA, while the multifunctional equivalent (2xC12AA) was characterized by good anti-adhesive activity. All tested compounds are non-mutagenic and cause low hemolysis of sheep erythrocytes. Multifunctional and gemini surfactants are also non-toxic.

Exploring the thermodynamic properties of 2-Methyl-1-butanol and C7-C10 alcohols through CPA modeling and experimental analysis

This paper presents an investigation into the thermodynamic and transport characteristics of 2-methyl-1-butanol and C7-C10 normal alcohols (1-heptanol to 1-decanol), with a specific focus on their binary mixtures. The experimental analysis encompassed a temperature range of 293.15 to 323.15 K, during which the density and viscosity of these mixtures were measured. The study reveals that all the binary mixtures exhibit positive excess molar volumes, which progressively increase as the alkyl chain length in the alcohols increases. Simultaneously, the observed viscosity deviations consistently display negative values across all the mixtures, becoming more pronounced as the alkyl chain lengthens. This behavior of the mixtures highlights the weak molecular interactions between 2-methyl-1-butanol and alcohols. In conjunction with the experimental work, this study utilizes the Cubic-Plus-Association (CPA) model to establish a correlation between the densities of these binary mixtures. The model demonstrates a satisfactory agreement with the experimental densities, signifying its efficacy in correlating the density behavior of such mixtures. The largest discrepancy between the experimental data and the correlated values from the CPA model was observed in the mixture of 2-methyl-1-butanol with 1-heptanol, amounting to a mere 0.29 %. This minor deviation underscores the correlation of the CPA model in reproducing experimental results.

Increasing terminal alkyl chain length for a better small molecule organic solar cell donor

Optimizing the alkyl chains within a terminal group is considered to be a highly effective approach for boosting the power conversion efficiency (PCE) of all small-molecule organic solar cells (ASM-OSCs). In this study, we focus on designing and synthesizing small molecular (SM) donor compounds with different end-group alkyl chain lengths to study their impact on OSC performance. Under optimized conditions, OSC devices based on BTR-Cl-C8:Y6 demonstrate higher PCE of 14.43 % compared to those based on BTR-Cl:Y6. Moreover, BTR-Cl-C8 exhibits reduced levels of bimolecular recombination and trap-assisted recombination, enhanced capability for exciton dissociation and charge collection, and extended carrier lifetimes. These results highlight the significance of molecular design strategies in optimizing OSC performance and offer valuable insights for the development of efficient and stable ASM-OSCs.

Synthesis, characterization and performance evaluation of different alkyl chain lengths flame-retardant plasticizers for poly(vinyl chloride) derived from sustainable vanillic acid

The current market for poly(vinyl chloride) (PVC) plasticizers is dominated by flammable petroleum-based compounds, accounting for over 80 % of the total share. Due to their high flammability, the search for novel approaches to enhance the fire resistance of flexible PVC has gained urgency. However, traditional flame-retardant schemes suffer from shortcomings such as poor compatibility, inferior long-term performance, and weak mechanical properties. Herein, we synthesized a novel biobased flame-retardant plasticizer (VAn-P) using vanillic acid as a skeleton. This plasticizer exhibits remarkable properties, including a substantially lower glass transition temperature compared to unplasticized PVC. The binding energy between VAn-P and PVC is calculated to be –33.30 kcal/mole, indicating a strong interaction. Furthermore, the maximum elongation at break of VAn-P plasticized PVC is 16 times higher than that of unmodified PVC. All PVC samples plasticized with VAn-P achieved a UL-94 VTM-0 rating. TGA-FTIR analysis revealed that the flame-retarding mechanism of VAn-P involves solid-phase action, significantly delaying the dehydrochlorination process of PVC. Moreover, VAn-P exhibits superior migration resistance compared to dioctyl phthalate (DOP). We also investigated the effects of alkyl chain lengths in VAn-P on various properties of PVC blends, including thermal stability, flame retardancy, mechanical properties, and optical performance. The toxicity of vanillic acid-based flame-retardant plasticizer has undergone an initial assessment. Overall, this green plasticizer is expected to endow polymers with high plasticizing performance and flame retardancy, providing a novel and sustainable approach for the synthesis of functional plasticizers.