Search

Underwater adhesives are critical for many applications, including marine coatings, sealants, and medical devices. Research on natural underwater adhesives has shown that L-3,4-dihydroxyphenylalanine (DOPA) and amyloid nanostructures are vital to their adhesive abilities. The fusion of DOPA-containing chains and amyloid-forming peptides creates a new space for designing underwater adhesives capable of multi-surface adhesion. One critical question for this design is the interplay between the DOPA and amyloid-forming peptide regions. Here we investigate the effect of the sequence pattern of DOPA-containing chains on the aggregation conformation of conjugates. Discontinuous molecular dynamics simulations were performed for fourteen DOPA-amyloid conjugates with different sequence patterns along the DOPA-containing portion. The amyloid-forming portion is represented by KLVFFAE from the Aβ42 peptide. The structural properties of the DOPA-amyloid conjugates are characterised by the percentages of ordered secondary structures and residue-residue contact maps. The results showed that certain patterns of DOPA and glycine in the DOPA-containing tail allowed the KLVFFAE portions of the conjugates to form distinct ordered β-sheets, and the DOPA-containing portion and the KLVFFAE portion of the conjugates to remain separated both within the same chain and amongst different chains. Among the designs, the most promising sequences are KLVFFAE-G-YYGYYGYY (where Y represents DOPA) and KLVFFAE-G-YYYYGGGG. [ABSTRACT FROM AUTHOR]

Sodium- (Na+) and potassium- (K+) ion batteries are cost-effective alternatives to lithium-ion (Li+) batteries due to the abundant sodium and potassium resources. Solid polymer electrolytes (SPEs) are essential for safer and more efficient Na+ and K+ batteries because they often exhibit low ionic conductivity at room temperature. While zwitterionic (ZW) materials enhance Li+ battery conductivity, their potential for Na+ and K+ transport in batteries remains unexplored. In this study, we investigated the effect of three ZW molecules (ChoPO4, i.e., 2-methacryloyloxyethyl phosphorylcholine, ImSO3, i.e., sulfobetaine ethylimidazole, and ImCO2, i.e., carboxybetaine ethylimidazole) on the dissociation of Na+ and K+ coordination with ethylene oxide (EO) chains in EO-based electrolytes through molecular dynamics simulations. Our results showed that ChoPO4 possessed the highest cation–EO10 dissociation ability, while ImSO3 exhibited the lowest. Such dissociation ability correlated with the cation–ZW molecule coordination strength: ChoPO4 and ImSO3 showed the strongest and the weakest coordination with cations. However, the cation–ZW molecule coordination could slow the cationic diffusion. The competition of these effects resulted in accelerating or decelerating cationic diffusion. Our simulated results showed that ImCO2 enhanced Na+ diffusion by 20%, while ChoPO4 and ImSO3 led to a 10% reduction. For K+, ChoPO4 reduced its diffusion by 40%, while ImCO2 and ImSO3 caused a similar decrease of 15%. These findings suggest that the ZW structure and the cationic size play an important role in the ionic dissociation effect of ZW materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrogen bond microstructure of DESs and lignin played a major role in dissolution. • Strong dissolution abilities of the Lac:ChCl and Oxa:ChCl solvents for GGM and GSM were due to the different HB interactions. • Large extended structure of lignin would increase the active exposed areas of β–O–4 bond in DES solvents. • Small |HOMO–LUMO| gap suggested that GGM and GSM had high reactivities in the Lac:ChCl and Oxa:ChCl solvents. • Average surface potential charge confirmed that solvents had different solubilities and effects on the β–O–4 bond. Acid choline chloride (ChCl)–based deep eutectic solvents (DESs), are widely used as effective green solvents of lignin, which contributes to the high–value application of biomass. Understanding the underlying microscopic-scale lignin dissolution mechanism of different acid ChCl–based DESs is important for further DES design due to the heterogeneous and refractory structure of lignin. In this study, we employed molecular dynamics and quantum mechanics methods to investigate the behavior of lignin dimers (guaiacyl–guaiacyl [GGM] and guaiacyl–syringyl [GSM] dimers) in three acid ChCl–based DESs ([i] lactic acid [Lac]:ChCl [2:1], [ii] levulinic acid [Lev]:ChCl [2:1], and [iii] oxalic acid [Oxa]:ChCl [1:1]). Results showed that the dissolution tendencies of different lignin dimers in the three solvents followed different orders. Microstructural analysis revealed that the microstructure of the hydrogen bond (HB) between DESs and lignin dimer played a major role in dissolution. The high dissolution abilities of the Lac:ChCl and Oxa:ChCl solvents for GGM and GSM, respectively, can be attributed to the strong HB interactions between acid–GGM and Chol–GSM, respectively. Moreover, the large extended structure of the lignin dimer would increase the active area (β–O–4 had a large exposed area) in DES solvents. The highest occupied molecular orbital and lowest unoccupied molecular orbital gap between lignin dimers and choline molecules in the three solvents suggested that GGM and GSM had higher reactivities in Lac:ChCl and Oxa:ChCl solvents, respectively, than in other solvents. Finally, the statistical analysis of average surface potential charges further confirmed the different solubilities of the three solvents for different lignin dimers and their effect on β–O–4 bonds. [ABSTRACT FROM AUTHOR]

As a growing concern in aqueous systems, micro- and nano-plastics, especially nanoplastics (NPs), have been widely detected in the environment and organisms, posing a potential threat to ecosystems and human health. Hydrophobic deep eutectic solvents (HDESs) have emerged as environmentally friendly solvents that have shown promise for extracting pollutants from water, either for detection or removal purposes. Herein, we investigated the extraction of polystyrene (PS) and polyethylene terephthalate (PET) NPs from aqueous solution using lignin based HDESs as sustainable solvents. Rapid extraction of both PET and PS NPs was observed with the high extraction efficiency achieved (> 95%). The extraction capacities for PET and PS could reach up to 525.877 mg/mL and 183.520 mg/mL, respectively, by the Thymol-2,6-dimethoxyphenol 1:2 HDES. Moreover, the extraction mechanism was studied using various techniques including Fourier-transform infrared analysis, contact angle measurements, molecular dynamics simulation, kinetics, and isotherm studies. This work lays a foundational basis for the future development of innovative HDES-based technologies in the detection and remediation of NPs as part of the grand challenge of plastic pollution. [Display omitted] • Sustainable lignin-based HDESs efficiently extracted NPs with extraction rates > 95%. • Physical interactions were the main driving force for the extraction process. • HDES-water interfacial properties could influence the extraction efficiency. • The dynamics and equilibrium states of NP extraction were studied. • High extraction capacities for NPs could be achieved. [ABSTRACT FROM AUTHOR]