High Interfacial Adhesion Research Articles

Localized surface roughening to improve adhesion of electroless seed layer in through-glass vias

This article reports the improvement of the adhesion of the electroless seed layer deposited on glass substrates used in creating through-glass vias (TGV) by localized surface roughening. Four glass substrates having varying roughness characteristics were prepared by electrochemical discharge machining (ECDM) and ultrasonic machining (USM). The electroless nickel seed layer was deposited directly on glass without any adhesion layer, followed by electrodeposited copper layers. In-depth surface topography and morphology analysis reveal the mechanism behind the improved adhesion during standard peel and cross-hatch adhesion tests, which were used to determine the interlayer adhesion.Localized roughening techniques generated specific microfeatures, i.e., microgrooves (in USM) or ridges (in ECDM), increasing the surface area. These features acted as interlocking/nucleation sites to hold the electroless nickel atoms, resulting in higher interfacial adhesion. USM-roughened samples exhibited stronger interfacial adhesion than their ECDM-roughened counterparts, which indicated that the interlayer adhesion depends on topography and the roughened surface's morphology. The surface with negative skewness and positive excess kurtosis promotes mechanical interlocking, offering a promising strategy for enhancing interlayer adhesion. Finally, conformal deposition in a 6 × 6 array of through-holes having an aspect ratio of ∼4 was also demonstrated.

Reversibly stable and highly stretchable transparent polymer nanocomposite adhesives using hierarchical spring-like molecular nanobridges

For the development of stretchable optoelectronic devices, optically transparent composite adhesives should afford reversible stretchability and high optical transmittance as well as strong interfacial adhesion. However, simultaneous achievement of these essential prerequisites for advanced stretchable optical composite adhesives remains challenging. Herein, we offer an unprecedented approach for the fabrication of reversibly stretchable and optically transparent polymer nanocomposite adhesives based on the construction of hierarchical elastic molecular nanobridges between rigid-flexible hybrid nanoparticles and matrix resin. Photoreactive flexible poly(propylene glycol) (meth)acrylate chains were chemically combined with a rigid nano-silica core to form rigid and flexible hybrid nanoparticles. Subsequently, multiple elastic molecular nanobridges between the embedded hybrid nanoparticles and acrylate resin matrix were constructed inside the polymer composite through UV curing, which results in a stretchable interconnection that allows efficient repeated stretching and recovery of stretchable polymer nanocomposite adhesives. The newly fabricated nanocomposite adhesive film with a low content of rigid-flexible hybrid nanoparticles afforded an excellent reversible stretchability and outstanding cyclic elastic durability, and simultaneously maintained high optical transparency (95.1%) and interfacial adhesion strength (21.5 N/25 mm) of the film compared to those of conventional optical adhesive film.

Upcycling of Carbon Fiber/Thermoset Composites into High‐Performance Elastomers and Repurposed Carbon Fibers

AbstractRecycling of carbon fiber‐reinforced polymer composites (CFRCs) based on thermosetting plastics is difficult. In the present study, high‐performance CFRCs are fabricated through complexation of aromatic pinacol‐cross‐linked polyurethane (PU−AP) thermosets with carbon fiber (CF) cloths. PU−AP thermosets exhibit a breaking strength of 95.5 MPa and toughness of 473.6 MJ m−3 and contain abundant hydrogen‐bonding groups, which can have strong adhesion with CFs. Because of the high interfacial adhesion between CF cloths and PU−AP thermosets and high toughness of PU−AP thermosets, CF/PU−AP composites possess a high tensile strength of >870 MPa. Upon heating in N,N‐dimethylacetamide (DMAc) at 100 °C, the aromatic pinacols in the CF/PU−AP composites can be cleaved, generating non‐destructive CF cloths and linear polymers that can be converted to high‐performance elastomers. The elastomers are mechanically robust, healable, reprocessable, and damage‐resistant with an extremely high tensile strength of 74.2 MPa and fracture energy of 149.6 kJ m−2. As a result, dissociation of CF/PU−AP composites enables the recovery of reusable CF cloths and high‐performance elastomers, thus realizing the upcycling of CF/PU−AP composites.

Upcycling of Carbon Fiber/Thermoset Composites into High-Performance Elastomers and Repurposed Carbon Fibers.

Recycling of carbon fiber-reinforced polymer composites (CFRCs) based on thermosetting plastics is difficult. In the present study, high-performance CFRCs are fabricated through complexation of aromatic pinacol-cross-linked polyurethane (PU-AP) thermosets with carbon fiber (CF) cloths. PU-AP thermosets exhibit a breaking strength of 95.5 MPa and toughness of 473.6 MJ m-3 and contain abundant hydrogen-bonding groups, which can have strong adhesion with CFs. Because of the high interfacial adhesion between CF cloths and PU-AP thermosets and high toughness of PU-AP thermosets, CF/PU-AP composites possess a high tensile strength of >870 MPa. Upon heating in N,N-dimethylacetamide (DMAc) at 100 °C, the aromatic pinacols in the CF/PU-AP composites can be cleaved, generating non-destructive CF cloths and linear polymers that can be converted to high-performance elastomers. The elastomers are mechanically robust, healable, reprocessable, and damage-resistant with an extremely high tensile strength of 74.2 MPa and fracture energy of 149.6 kJ m-2. As a result, dissociation of CF/PU-AP composites enables the recovery of reusable CF cloths and high-performance elastomers, thus realizing the upcycling of CF/PU-AP composites.

Wettability and microstructural evolution of copper filler in W and EUROFER brazed joints

In terms of wettability, active systems are characterized by a reduction in interfacial energy as the time at specific conditions is increased. This article aims to investigate the evolution of wettability and microstructure, which undergoes a critical transformation at temperatures and dwell times near brazing conditions due to their significant impact on resultant mechanical properties. The objective is to enhance wettability and prevent the formation of different phases that can occur rapidly within the brazing window conditions. Up to 1105 °C, complete fusion of the filler does not occur. However, once it happens, the expansion of the copper filler in EUROFER increases up to 400%, and the contact angle reduces from 100° to 10°, indicating an active wetting behavior. On the other hand, when copper is used with tungsten, an inert behavior is observed, maintaining the contact angle around 70°. Brazed joints carried out under the most promising wetting conditions demonstrated that at 1110 °C-1 min, various phenomena began to occur. This includes solid-state diffusion of copper in the EUROFER, following the austenitic grain boundaries, and partial dissolution of Fe in the copper braze. Increasing the brazing time from 2 to 5 min achieved high interfacial adhesion properties and controlled the diffusion layer and Fe-rich band formed at the W-braze interface, resulting in the best mechanical results (295 MPa).

Aggregation and Interfacial Adhesion of Nano-Sb2O3 Particles in Poly(Butylene Terephthalate) Composites: Effect of Surface Structure of the Nanoparticles

To study the effect of different surface structures on the aggregation level and interfacial adhesion, nano-Sb2O3 particles were treated with cetyltrimethylammonium bromide (CTAB), silane coupling agent KH550 and their compounds (CTAB + KH550). The surface properties and morphologies of the nano-Sb2O3 particles were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The aggregation level and interfacial adhesion of nano-Sb2O3 particles within PBT matrix were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), and quantitatively evaluated by some semi-empirical parameters including aggregates size (Dagg ), real filling degree (Vre ), interfacial adhesion ( B ) and aggregated interfacial adhesion (Bagg ) from the tensile strength and the Young’s modulus measurements. The results showed that the highest interfacial adhesion and lowest aggregation level were obtained for the CTAB + KH550 modified nano-Sb2O3/PBT composites followed by the KH550 modified, CTAB modified and bare nano-Sb2O3/PBT composites, respectively.

Surface treatment of stainless steel (SUS) to improve interfacial adhesion of SUS/polymer hybrid bilayer composites

The use of hybrid metal/polymer structure is an efficient strategy for weight reduction in automotive applications. The poor interfacial adhesion between metals and polymers can be solved by using coupling agent (compatibilizer) and through surface treatments, adding new functionalities and a rough surface. In this study, the stainless steel (SUS) surface treatments were systematically examined using various etching and functionalizing solutions, such as hydrochloric acid (HCl), nitric acid (HNO3), acetic acid (CH3COOH), phosphoric acid (H3PO4), copper sulfate (CuSO4), ethanol (C2H5OH), fluorozirconic acid (H2ZrF6), sodium hydroxide (NaOH), acetone (C3H6O), and their mixtures. An HCl/CuSO4 aqueous solution was the most efficient surface treatment for SUS, resulting in the highest interfacial adhesion with polyamide 6,6 (lab shear strength: from 1.7 to 12.7 MPa, and toughness: from 4.9 to 35.4 N/m2). The etching process was further investigated by optimizing the etching time and temperature. The treated surfaces were characterized by surface roughness, morphology, contact angle, elemental analysis, and single–lap shear tests.

Enhanced Mechanical and Self-Healing Properties of Carbon Fiber-Reinforced Epoxy Laminates Using In Situ-Grown ZnO Nanorods and Thermo-Reversible Bonds.

Advanced hierarchical carbon fiber epoxy laminates with an engineered interface using in situ-grown ZnO nanorods on carbon fiber resulted in strong mechanical interlocking with the matrix. To further strengthen the interface, "site-specific" modification was realized by modifying the ZnO nanorods with bismaleimide (BMI), which facilitates "thermo-reversible" bonds with graphene oxide (GO) present in the matrix. The resulting laminates exhibited an improvement in flexural strength by 20% and in interlaminar shear strength (ILSS) by 28%. In order to gain a mechanistic insight, few laminates were prepared by "nonselectively" modifying the ZnO-grown carbon fiber (CF) with BMI. The "nonselectively" modified laminates showed flexural strength and ILSS improvement by 43 and 39%, respectively. The "nonselective" modification resulted in a strong improvement in mechanical properties; however, the "site-specific" modification yielded a higher self-healing efficiency (81%). Raman spectroscopy, scanning electron microscopy (SEM) micrographs, atomic force microscope (AFM) analysis, and contact angle analysis indicated a strong interaction of the modified CFs with the resin. Enhanced surface area and energy, along with a decrease in segmental molecular mobility observed from dynamic mechanical analysis, confirmed the mechanism for a better performance. Microscopic images revealed an improved interfacial behavior of the fractured samples, indicating a higher interfacial adhesion in the modified laminates. Besides mechanical properties, these laminates also showed excellent electromagnetic interference (EMI) shielding performance. The laminates with only ZnO-modified CF showed a high shielding effectiveness of -47 dB.

Interface deciphering for highly interfacial adhesion and efficient heat energy transfer

Interfacial adhesion and interfacial thermal resistance (ITR) are two critical factors in the interfacial force and energy transfer, but it is difficult to simultaneously achieve the desirable interfacial adhesion and ITR. Here, we overcome this challenge by fabricating an elastomer composite consisting of polydimethylsiloxane (PDMS) and micro-scale spherical aluminum (Al) fillers, which offers the high adhesion strength (1.28 MPa), high interfacial adhesion energy (528.4 J/m2), and low ITR (0.028 mm2·K/W) between the PDMS/Al elastomer composite and substrates. We further propose a quantified physical model to establish the relationship between interfacial adhesion and ITR for low phonon mismatch interfaces. This work will contribute to the development of interface science and guide the regulation of force and energy transfer at interface for wide range applications, such as electronic packaging, thermal storage, sensors, and medicine.

Continuous Amorphous Metal-Organic Frameworks Layer Boosts the Performance of Metal Anodes.

Employing metal anodes can greatly increase the volumetric/gravimetric energy density versus a conventional ion-insertion anode. However, metal anodes are plagued by dendrites, corrosion, and interfacial side reaction issues. Herein, a continuous and flexible amorphous MOF layer was successfully synthesized and used as a protective layer on metal anodes. Compared with the crystalline MOF layer, the continuous amorphous MOF layer can inhibit dendrite growth at the grain boundary and eliminate ion migration near the grain boundary, showing high interfacial adhesion and a large ion migration number (tZn2+ = 0.75). In addition, the continuous amorphous MOF layer can effectively solve several key challenges, e.g., corrosion of the zinc anode, hydrogen evolution reaction, and dendrite growth on the zinc surface. The prepared Zn anode with the continuous amorphous MOF (A-MOF) layer exhibited an ultralong cycling life (around one year, more than 7900 h) and a low overpotential (<40 mV), which is 12 times higher than that of the crystalline MOF protective layer. Even at 10 mA cm-2, it still showed high stability for more than 5500 cycles (1200 h). The enhanced performance is realized for full cells paired with a MnO2 cathode. In addition, a flexible symmetrical battery with the Zn@A-ZIF-8 anode exhibited good cyclability under different bending angles (0°, 90°, and 180°). More importantly, various metal substrates were successfully coated with compact A-ZIF-8. The A-ZIF-8 layer can obviously improve the stability of other metal anodes, including those of Mg and Al. These results not only demonstrate the high potential of amorphous MOF-decorated Zn anodes for AZIBs but also propose a type of protective layer for metal anodes.

Preparation of strong, water retention, and multifunctional soybean flour-based adhesive inspired by lobster shells and milk skin

The development of a water-retaining soybean flour-based adhesive with high water resistance, interfacial adhesion and mildew resistance is significant in replacing petroleum-based aldehyde-based resin. Drawing inspiration from lobster shells, soybean flour (SF), self-synthesized epoxy hyperbranched hydroxyethyl cellulose (EH) and calcium phosphate (CaP) oligomers were employed to prepare organic-inorganic hybrid composite adhesives based on hyperbranched structure. The EH component, abundant in active groups, enhanced the interfacial adhesion of the adhesives and served as an organic carrier for the mineralization of CaP oligomers. Prior to adhesive solidification, CaP oligomers mineralized to form an inorganic film akin to milk skin, which prevented water evaporation, resulting in a water retention time of 100 min for the adhesive. During adhesive curing, CaP oligomers with fluid-like behavior polymerized and mineralized, ultimately forming a continuous inorganic network of CaP crystals. This network, combined with the organic substrates (SF and EH), constituted an organic-inorganic hybrid structure, which bolstered the water and mildew resistance (20 days) of the adhesives. The prepressing intensity and wet shear strength of the resultant plywood increased by 168% and 396% to 0.67 MPa and 1.39 MPa, respectively, compared to those of the unmodified adhesive. The strength reached the leading level of the reported soybean flour adhesives. The biomimetic strategy employed here can be extended to high-performance gels and membrane materials, offering a novel modification approach for bio-composites.

Constructed multifunctional CuOx core and electrodeposited nickel‑cobalt sulfide for high areal energy-power density supercapacitor

Construction of heterostructure is regarded as an effective strategy for enhancing the electrochemical performance of electrode materials for supercapacitor. Moreover, the relatively poor conductivity and commonly structural design severely decrease the electron transfer ability and surface utilization of nickel cobalt sulfides during charge-discharge process. In this work, three unique core structures of Cu, CuO, and CuOx (Cu-Cu2O-CuO) were successfully constructed on copper foam via an in-situ redox strategy. Among them, the CuOx cores exhibit higher capacity and lower voltage drop because of the high conductivity of Cu, the generation of built-in electric field between Cu2O and CuO, as well as rich active areas. Three-dimensional interconnected NiCoS nanosheets grown on the surface of CuOx cores with high areal-loading and robust interfacial adhesion. Benefited from the unique structural advantages and synergistic effect of multi-metallic active centers, the CuOx/NiCoS composite exhibits high specific capacitance of 3305 mF cm−2 at 5 mA cm−2, outstanding rate capability of 68.3% when the current density increases to 60 mA cm−2, and long-term lifespan. Notably, the assembled CuOx/NiCoS//PAC asymmetric supercapacitor delivers a high areal energy density and power density (263.3 μWh cm−2 at 2.4 mW cm−2), which can drive some small electronic devices. This study offers a novel pathway for further design of a core-shell structured electrode materials with an enhanced capacity and rate capability for advanced energy storage devices.

Super toughened blends of poly(lactic acid) and poly(butylene adipate-co-terephthalate) injection-molded foams via enhancing interfacial compatibility and cellular structure

Biodegradable poly(lactic acid) (PLA) foams have drawn increasing attention due to environmental challenges and petroleum crisis. However, it still remains a challenge to prepare PLA foams with fine cellular structures and high impact property, which significantly hinders its widespread application. Herein, phase interface-enhanced PLA/ poly(butylene adipate-co-terephthalate) (PBAT) blend foam, modified by a reactive compatibilizer through a simple reactive extrusion, was produced via a core-back foam injection molding technique. The obtained PLA blend foams displayed an impact strength as high as 49.1 kJ/m2, which was 9.3 and 6.4 times that of the unmodified PLA/PBAT blend and its corresponding foam, respectively. It proved that the interfacial adhesion and cell size both strongly affected the impact strength of injection-molded PLA/PBAT foams, and two major conclusions were proposed. First, enhancing interfacial adhesion could cause a brittle-tough transition of PLA/PBAT foams. Additionally, for foams with high interfacial adhesion, small cell size (<12 μm) was more favorable for the stretching of cells and extension of the whitened region in comparison with big cell size (cell size >60 μm), leading to the drastic toughening of PLA blends. This study provides a feasible, industrially scalable and practical strategy to prepare super toughened and fully biodegradable PLA materials.

TiC–Fe gradient coating with high hardness and interfacial adhesion strength on cast iron prepared by in-situ solid-phase diffusion method

The improvement of comprehensive properties including hardness, toughness, wear, and adhesion strength of the coating-substrate system, especially avoiding the trade-off between the hardness and adhesion strength, is strongly required for various applications. Herein, an effective strategy is proposed, by in-situ solid-phase diffusion method, to fabricate a novel TiC–Fe gradient coating with high hardness and interfacial adhesion strength on cast iron. The eveloped coating was composed of equiaxed TiC particles and α-Fe phase. The microstructure was graded in TiC size and volume fraction. The formation of the graded microstructure was attributed to the nucleation-growth process controlled by diffusion of the carbon concentration gradient. The TiC volume fraction in the coating was as high as 95%. The phase interface (TiC/TiC interface and TiC/α-Fe interface) and the coating/substrate interface exhibited excellent interfacial bonding at the atomic scale. The novel gradient coating could simultaneously achieve high hardness (23.9 ± 1.3 GPa), high elastic modulus (265.7 ± 9.4 GPa), and excellent adhesion strength (>225 ± 10 MPa). Apparently, in-situ solid-phase diffusion method may provide a new route to fabricate TiC–Fe gradient coatings with high-volume fraction on steel/iron, capable of capable of exhibiting elevated hardness, high elastic modulus, excellent interfacial adhesion strength, and superior wear resistance.

Understanding and Engineering Interfacial Adhesion in Solid-State Batteries with Metallic Anodes.

High performance alkali metal anode solid-state batteries require solid/solid interfaces with fast ion transfer that are morphologically and chemically stable upon electrochemical cycling. Void formation at the alkali metal/solid-state electrolyte interface during alkali metal stripping is responsible for constriction resistances and hotspots that can facilitate dendrite propagation and failure. Both externally applied pressures (35-400 MPa) and temperatures above the melting point of the alkali metal have been shown to improve the interfacial contact with the solid electrolyte, preventing the formation of voids. However, the extreme pressure and temperature conditions required can be difficult to meet for commercial solid-state battery applications. In this review, we highlight the importance of interfacial adhesion or 'wetting' at alkali metal/solid electrolyte interfaces for achieving solid-state batteries that can withstand high current densities without cell failure. The intrinsically poor adhesion at metal/ceramic interfaces poses fundamental limitations on many inorganics solid-state electrolyte systems in the absence of applied pressure. Suppression of alkali metal voids can only be achieved for systems with high interfacial adhesion (i. e. 'perfect wetting') where the contact angle between the alkali metal and the solid-state electrolyte surface goes to θ=0°. We identify key strategies to improve interfacial adhesion and suppress void formation including the adoption of interlayers, alloy anodes and 3D scaffolds. Computational modeling techniques have been invaluable for understanding the structure, stability and adhesion of solid-state battery interfaces and we provide an overview of key techniques. Although focused on alkali metal solid-state batteries, the fundamental understanding of interfacial adhesion discussed in this review has broader applications across the field of chemistry and material science from corrosion to biomaterials development.

Polyethylene ceramic separators with semi-interpenetrating polymer network boosting fast-charging cycle capacity retention and safety for lithium-ion batteries

Fast-charging lithium-ion batteries (LIBs) have recently received significant attention. In current commercial LIBs, lithium precipitation frequently occurs under long-term cycling and fast-charging conditions, adversely affecting their cycle capacity retention and safety. The primary cause of lithium precipitation is electrolyte loss during long-term cycling. In this study, a thermoplastic polyurethane/polyurethane acrylate semi-interpenetrating polymer network ceramic separator with high electrolyte retention (200%) and interfacial adhesion (6.6 N) is prepared and without a decrease in the energy density. The LiNi0.8Mn0.1Co0.1O2/graphite batteries fabricated with this separator show excellent electrochemistry properties (300 cycles, 1.5 C, discharge capacity of 3677 mAh, capacity retention of 93%). Furthermore, this study presents a novel strategy to mitigate the issue of lithium precipitation in fast-charging LIBs. Therefore, this functional separator is a promising alternative for the conventional commercial polyvinylidene difluoride separators and provides a new avenue for developing the next generation of fast-charging devices.

A strategy for dual-networked epoxy composite systems toward high cross-linking density and solid interfacial adhesion

Epoxy composites (ECs) are used as epoxy molding compound (EMC), which significantly protects the integrated circuits from the humid environment. One of the major limitations with ECs is their phenomena of moisture absorption in humid environments, which drastically reduces their mechanical properties and hinders them from gaining widespread industrial applications. The low cross-linking density of conventional epoxy composites that can lead to intrinsically providing hydrophilic sites and low activation energy in water molecule diffusion. Herein, a dual-networked epoxy composite system as a platform technique by adopting strategically designed poly (methyl methacrylate)-b-(dimethyl aminoethyl methacrylate) (PMD) as polymer compatibilizer to improve the water absorption resistance and mechanical properties derived from good interfacial adhesion and high cross-linking density of epoxy/silica composites were investigated. The as-prepared dual-networked epoxy composite system demonstrates a high-water absorption suppression of about 166.78% and a high tensile modulus of 4.6 GPa, compared to other epoxy composites. In addition, the current strategy has excellent expandability to various fillers also applicable to diverse epoxy composite systems.

In situ formed LiF-Li3N interface layer enables ultra-stable sulfide electrolyte-based all-solid-state lithium batteries

Sulfide solid electrolytes are promising for high energy density and safety in all-solid-state batteries due to their high ionic conductivity and good mechanical properties. However, the application of sulfide solid electrolytes in all-solid-state batteries with lithium anode is restricted by the side reactions at lithium/electrolytes interfaces and the growth of lithium dendrite caused by nonuniform lithium deposition. Herein, a homogeneous LiF-Li3N composite protective layer is in situ formed via a manipulated reaction of pentafluorobenzamide with Li metal. The LiF-Li3N layer with both high interfacial energy and interfacial adhesion energy can synergistically suppress side reactions and inhibit the growth of lithium dendrite, achieving uniform deposition of lithium. The critical current densities of Li10GeP2S12 and Li6PS5Cl are increased to 3.25 and 1.25 mA cm−2 with Li@LiF-Li3N layer, which are almost triple and twice as those of Li-symmetric cells in the absence of protection layer, respectively. Moreover, the Li@LiF-Li3N/Li10GeP2S12/Li@LiF-Li3N cell can stably cycle for 9000 h at 0.1 mA cm−2 under 0.1 mA h cm−2, and Li@LiF-Li3N/Li6PS5Cl/Li@LiF-Li3N cell achieves stable Li plating/stripping for 8000 h at 0.1 mA cm−2 under 10 mA h cm−2. The improved dynamic stability of lithium plating/stripping in Li@LiF-Li3N/Li10GeP2S12 or Li6PS5Cl interfaces is proved by three-electrode cells. As a result, LiCoO2/electrolytes/Li@LiF-Li3N batteries with Li10GeP2S12 and Li6PS5Cl exhibit remarkable cycling stability of 500 cycles with capacity retentions of 93.5% and 89.2% at 1 C, respectively.

Achieving strong, stable, and durable underwater adhesives based on a simple and generic amino-acid-resembling design.

Developing underwater adhesives is important in many applications. Despite extensive progress, achieving strong, stable, and durable underwater adhesion via a simple and effective way is still challenging, mainly due to the conflict between the interfacial and bulk properties. Here, we report a unique bio-inspired strategy to facilely construct superior underwater adhesives with desirable interfacial and bulk properties. For adhesive design, a hydrophilic backbone is utilized to quickly absorb water for effective dehydration, and a novel amino acid-resembling functional block is developed to provide versatile molecular interactions for high interfacial adhesion. Moreover, the conjunction of these two components enables the generation of abundant covalent crosslinks for robust bulk cohesion. Such a rational design allows the adhesive to present a boosted underwater adhesion (3.92 MPa to glass), remarkable durability (maintaining high strength after one month), and good stability in various harsh environments (pH, salt, high temperature, and organic solvents). This strategy is generic, allowing the derivation of more similar adhesive designs easily and triggering new thinking for designing bio-inspired adhesives and beyond.

Correlation between interfacial adhesion and functional properties of corn stalk cellulose-reinforced corn starch-based biodegradable straws

To study correlation between interfacial adhesion and properties of corn starch/corn stalk cellulose (CSC) biodegradable straws, the interfacial adhesion and functional properties of the starch-based straws with different cellulose contents were analyzed and compared. The results showed that the starch/CSC straw with 1 % CSC (SC1) had the highest interfacial adhesion between starch and cellulose, resulting in higher mechanical properties and water resistance. Compared to starch/CSC straw with 0 % CSC, water absorption rate of SC1 decreased by 13.0 % (4 °C, 1 h) and 18.4 % (25 °C, 1 h), respectively. The fracture strength and fracture deformation increased by 47.8 % and 59.6 %, respectively. The strength increased by 3.93 (4 °C, 30 min) and 1.53 (25 °C, 30 min) times after soaking, respectively. The soil degradation rate of SC1 was 89.5 % on the 20th day and thermal degradation rate was 79.6 % at 600 °C. The SC1 with better properties (soil degradability, water resistant and mechanical properties) was as economical as paper straw.