Strain-induced Deformation Research Articles

Probing plastic deformation-related properties in static recrystallized Co–Cr–Fe–Ni–Mo alloy for biomedical applications

40Co–20Cr–16Fe–15Ni–7Mo (mass%, Co–Cr–Fe–Ni–Mo) alloys are currently used in biomedical implants such as balloon-expandable stents. Materials used as balloon-expandable stents are statically recrystallized and subsequently utilized within the body in a plastically deformed state. This study describes the microstructures and the mechanical and corrosive properties related to the plastic deformation of statically recrystallized Co–Cr–Fe–Ni–Mo alloys. The η-phase (M6X-M12X type, M: metallic elements; X: C and/or N) and M23X6-type precipitates were observed. The grain sizes of the recrystallized alloys were 6–92 μm. The mechanical properties were dependent on the grain size: the 0.2% proof strength and ultimate tensile strength increased and plastic elongation decreased with an increase in grain refinement. The stacking fault energy (SFE) of the Co–Cr–Fe–Ni–Mo alloy was determined by the width of partial dislocations, measured as 16 ± 3 mJ⋅m−2. Corresponding to this SFE, the formation of the ε-phase associated with strain-induced martensitic transformation and deformation twins were observed after plastic deformation. This suggests that the Co–Cr–Fe–Ni–Mo alloy exhibited a twinning-induced plasticity-like work-hardening mechanism. The polarization curves of the alloys in a simulated body fluid were not affected by the formation of precipitates (η-phase and M23X6-type) or plastic deformation, thereby suggesting that heat treatment does not deteriorate the corrosive property. The recrystallized alloy with a grain size of 36 μm had the ultimate tensile strength of more than 1000 MPa, 0.2% proof strength of less than 500 MPa, and plastic elongation greater than 70%. This alloy is expected to be applied in low-yield-strength-type balloon-expandable stents.

Mapping deformation dynamics to composition of topologically-active DNA blends.

Blends of circular and linear polymers have fascinated researchers for decades, and the role of topology on their stress response and dynamics remains fervently debated. While linear polymers adopt larger coil sizes and form stronger, more pervasive entanglements than their circular counterparts, threading of circular polymers by linear chains can introduce persistent constraints that dramatically decrease mobility, leading to emergent rheological properties in blends. However, the complex interplay between topology-dependent polymer overlap and threading propensity, along with the large amounts of material required to sample many compositions, has limited the ability to experimentally map stress response to composition with high resolution. Moreover, the role of supercoiling on the response of circular-linear blends remains poorly understood. Here, we leverage in situ enzymatic topological conversion to map the deformation dynamics of DNA blends with over 70 fractions of linear, ring and supercoiled molecules that span the phase space of possible topological compositions. We use OpTiDDM (optical tweezers integrating differential dynamic microscopy) to map strain-induced deformation dynamics to composition, revealing that strain-coupling, quantified by superdiffusive dynamics that are aligned with the strain, is maximized for blends with comparable fractions of ring and linear polymers. Increasing the supercoiled fraction dramatically reduces strain-coupling, while converting rings to linear chains offers more modest coupling reduction. We demonstrate that these results are a direct consequence of the interplay between increasing polymer overlap and decreasing threading probability as circular molecules are converted to linear chains, with a careful balance achieved for blends with ample ring fractions but devoid of supercoiled molecules.

Relaxation effects on the structural and piezoelectric properties of wurtzite ZnS and CdS thin films under in-plane strain

Through first-principles investigations, we examine variations in the atomic crystal structure, thermal stability, electronic structure, and piezoelectric properties of wurtzite ZnS and CdS under in-plane strain. We specifically aim to elucidate the distinct effects arising from two relaxation modes: elastic and non-elastic. Our analyses reveal that the in-plane strain-induced deformation behaviors and performance changes in these sulfides are remarkably similar, attributable to the similar atomic arrangements, anionic sulfur elements, and analogous cation electronic configurations. However, following non-elastic relaxation, enhanced robustness emerges in the lattice volume and chemical bonding, alongside stronger thermal stability and attenuated modifications in the piezoelectric coefficient. We posit that these marked discrepancies from elastic relaxation may originate from subtle differences in the electronegativities and d-orbital electron configurations between the Zn2+ and Cd2+ cations. By offering fundamental new insights into the atomic-scale relaxation phenomena in wurtzite binaries, this work significantly furthers the fundamental understanding of structure-property relationships in these materials. Moreover, delineating the precise impacts of elastic versus non-elastic relaxation serves as an effective tuning methodology to engineer the piezoelectric and electronic traits of sulfide compounds for cutting-edge applications.

Influence of uniaxial tensile strain on magnetization behavior of Fe-9wt%Ni steel

This study investigated the effects of uniaxial tensile strain on the magnetization process of an Fe-9wt%Ni (9Ni) alloy to increase understanding of its magnetic behavior. As the applied strain was increased from 0 to 14 %, the magnetization curve changed remarkably, particularly under a high-intensity magnetic field, and magnetic flux density, relative permeability, remanence, and coercive force degraded significantly, especially at strains greater than the upper yield point. Increase in tensile strain caused increase in hysteresis losses, primarily because strain induced crystal defects, which affected the rearrangement of magnetic domains. Increased dislocation density was the primary contributor to the observed deterioration in magnetic properties; changes in texture and phase had little influence. This finding indicates that strain-induced deformation strongly affects the magnetic behavior of 9Ni alloys; this insight will be useful in research aimed at mitigating welding defects such as arc blow, that are attributed to the magnetization of Ni steel.

Strain-induced self-rolled-up microtubes for multifunctional on-chip microfluidic applications.

On-chip microfluidics are characterized as miniaturized devices that can be either integrated with other components on-chip or can individually serve as a standalone lab-on-a-chip system for a variety of applications ranging from biochemical sensing to macromolecular manipulation. Heterogenous integration with various materials and form factors is, therefore, key to enhancing the performance of such microfluidic systems. The fabrication of complex three-dimensional (3D) microfluidic components that can be easily integrated with other material systems and existing state-of-the-art microfluidics is of rising importance. Research on producing self-assembled 3D architectures by the emerging self-rolled-up membrane (S-RuM) technology may hold the key to such integration. S-RuM technology relies on a strain-induced deformation mechanism to spontaneously transform stacked thin-film materials into 3D cylindrical hollow structures virtually on any kind of substrate. Besides serving as a compact microfluidic chamber, the S-RuM-based on-chip microtubular architecture exhibits several other advantages for microfluidic applications including customizable geometry, biocompatibility, chemical stability, ease of integration, uniform field distributions, and increased surface area to volume ratio. In this Review, we will highlight some of the applications related to molecule/particle sensing, particle delivery, and manipulation that utilized S-RuM technology to their advantage.

Probing Relative Humidity Impact on Biological Protein Bovine Serum Albumin and Bovine Submaxillary Gland Mucin by Using Contact Resonance Atomic Force Microscopy.

In biomaterials, a substantial amount of research has been placed on the mechanical properties of biomolecules and their interactions with body fluids. Bovine serum albumin (BSA) is a widely studied model protein, while bovine submaxillary gland mucin (BSM) is another cow-derived protein frequently employed in research. Films were examined with contact resonance atomic force microscopy (CR-AFM), and the results showed that the mechanical characteristics of the films were affected by the relative humidity. We quantitatively analyze the viscoelasticity of these proteins after they have been subjected to humidity by measuring the resonance frequency and quality factor. The findings indicate that prolonged humidity exposure has a different effect on the mechanical properties of BSA and BSM films. The results show that after exposure to humidity, the resonance peaks of BSA shift to the left, indicating stiffness, while those of BSM shift to the right, indicating hydration. Moreover, BSM's hydration is caused by relative humidity, leading to a constant increase in resonance frequency and material softness. Contrarily, BSA showed a decrease in contact resonance frequency due to ongoing strain-induced deformation, indicating increased material stiffness. The findings have significance for the design and development of biomaterials for a variety of applications, such as the delivery of drugs, the engineering of tissue, and the development of biosensors. Our research demonstrates that CR-AFM has the potential to become a non-invasive and sensitive method that can be used to characterize the mechanical characteristics of biomolecules and their interactions with bodily fluids.

Highly Strain-Stable Intrinsically Stretchable Olfactory Sensors for Imperceptible Health Monitoring.

Intrinsically stretchable gas sensors possess outstanding advantages in seamless conformability and high-comfort wearability for real-time detection toward skin/respiration gases, making them promising candidates for health monitoring and non-invasive disease diagnosis and therapy. However, the strain-induced deformation of the sensitive semiconductor layers possibly causes the sensing signal drift, resulting in failure in achievement of the reliable gas detection. Herein, a surprising result that the stretchable organic polymers present a universal strain-insensitive gas sensing property is shown. All the stretchable polymers with different degrees of crystallinity, including indacenodithiophene-benzothiadiazole (PIDTBT), diketo-pyrrolo-pyrrole bithiophene thienothiophene (DPPT-TT) and poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-alt-[1,2,5]thiad-iazolo [3,4-c] pyridine] (PCDTPT), show almost unchanged gas response signals in the different stretching states. This outstanding advantage enables the intrinsically stretchable devices to imperceptibly adhere on human skin and well conform to the versatile deformations such as bending, twisting, and stretching, with the highly strain-stable gas sensing property. The intrinsically stretchable PIDTBT sensor also demonstrates the excellent selectivity toward the skin-emitted trimethylamine (TMA) gas, with a theoretical limit of detection as low as 0.3ppb. The work provides new insights into the preparation of the reliable skin-like gas sensors and highlights the potential applications in the real-time detection of skin gas and respiration gas for non-invasive medical treatment and disease diagnosis.

Design and performance evaluation of a multi-disc magnetorheological fluid brake for A00-class minicars

This paper presents the design and performance evaluation of a multi-disc magnetorheological fluid (MRF)-based brake (MRB) for A00-class minicars. The braking performance of the MRB is studied by means of theoretical analysis and experimental verification. Firstly, the MRB is designed according to the shear model of the MRF, and the structure optimization is carried subsequently. Secondly, multi-physical simulations of the MRB are conducted to investigate the transient temperature field, thermal stress and thermal strain distribution of the MRB under different braking models; Finally, a performance evaluating testbed is built to experimentally assess the braking performance of the MRB. The results indicate that the theoretical braking torque of the MRB fulfills the target value. The thermal strain-induced deformation of the disc is minimal and has a negligible effect on the torque output. In addition, the MRB is experimentally validated to exhibit excellent braking performance in terms of sufficient torque output capacity, rapid response, low temperature rise characteristic, as well as favorable velocity following property.

All-atom molecular dynamics study of the impact fracture of glassy polymers. III: Compressive fracture of PC and PMMA

The compressive fracture of glassy polymers was investigated by performing all-atomistic molecular dynamics calculations for poly (methyl methacrylate) (PMMA) and polycarbonate (PC). The microscopic behaviors such as conformation changes of PMMA were different from that of PC by the analysis of one- and two radial distribution functions and bond breakages. Both brittle PMMA and ductile PC underwent ductile fracture when compressed and exhibited stress-strain curves comparable to those obtained experimentally. The compression process demonstrated a similar but not identical mechanism to extension: first, strain-induced affine deformation resulted in volume reduction in the elastic deformation; second, accumulated stress caused plastic deformation and strain softening accompanied by volume expansion; third, strain hardening occurred, but because of van der Waals repulsion instead of the entanglement networks. The volume expansion during strain softening showed no correlation with the increase in the dihedral transition rate. Structural anisotropy was observed as the strain increased, leading to the alignment of the polymer chain to the plane perpendicular to the compression direction and anisotropic density distribution.

Remarkable Thermal Conductivity Reduction of Silicon Nanowires during the Bending Process.

The one-dimensional geometry of silicon nanowire helps to overcome the rigid and brittle nature of bulk silicon and enables it to withstand substantial bending stresses. This provides exciting opportunities for the development of flexible electronics. The bending strain introduces atomic displacement in the lattice structure, which inherently has a significant impact on the thermal conductivity. The strain-dependent thermal conductivity of silicon nanowire is crucial to the thermal management and performance of flexible electronic devices. However, in situ thermal conductivity measurement of bending silicon nanowires remains challenging and unreported due to the varying thermal contact resistances between the sample and sensor/heat sink. In this study, the Raman spectroscopy-assisted steady state thermal conductivity measurement method is coupled with a micromanipulation system to successively monitor the thermal conductivity variation of silicon nanowires during the bending process. The result shows that the thermal conductivity of silicon nanowires steeply decreases 55-78% owing to the strain-induced structural deformation during bending. Furthermore, the proposed in situ thermal conductivity measurement method can also be extended to other nanomaterials.

Localised strain and doping of 2D materials.

There is a growing interest in 2D materials-based devices as the replacement for established materials, such as silicon and metal oxides in microelectronics and sensing, respectively. However, the atomically thin nature of 2D materials makes them susceptible to slight variations caused by their immediate environment, inducing doping and strain, which can vary between, and even microscopically within, devices. One of the misapprehensions for using 2D materials is the consideration of unanimous intrinsic properties over different support surfaces. The interfacial interaction, intrinsic structural disorder and external strain modulate the properties of 2D materials and govern the device performance. The understanding, measurement and control of these factors are thus one of the significant challenges for the adoption of 2D materials in industrial electronics, sensing, and polymer composites. This topical review provides a comprehensive overview of the effect of strain-induced lattice deformation and its relationship with physical and electronic properties. Using the example of graphene and MoS2 (as the prototypical 2D semiconductor), we rationalise the importance of scanning probe techniques and Raman spectroscopy to elucidate strain and doping in 2D materials. These effects can be directly and accurately characterised through Raman shifts in a non-destructive manner. A generalised model has been presented that deconvolutes the intertwined relationship between strain and doping in graphene and MoS2 that could apply to other members of the 2D materials family. The emerging field of straintronics is presented, where the controlled application of strain over 2D materials induces tuneable physical and electronic properties. These perspectives highlight practical considerations for strain engineering and related microelectromechanical applications.

Mechanochemically assisted morphing of shape shifting polymers.

Morphing in creatures has inspired various synthetic polymer materials that are capable of shape shifting. The morphing of polymers generally relies on stimuli-active (typically heat and light active) units that fix the shape after a mechanical load-based shape programming. Herein, we report a strategy that uses a mechanochemically active 2,2'-bis(2-phenylindan-1,3-dione) (BPID) mechanophore as a switching unit for mechanochemical morphing. The mechanical load on the polymer triggers the dissociation of the BPID moiety into stable 2-phenylindan-1,3-dione (PID) radicals, whose subsequent spontaneous dimerization regenerates BPID and fixes the temporary shapes that can be effectively recovered to the permanent shapes by heating. A greater extent of BPID activation, through a higher BPID content or mechanical load, leads to higher mechanochemical shape fixity. By contrast, a relatively mechanochemically less active hexaarylbiimidazole (HABI) mechanophore shows a lower fixing efficiency when subjected to the same programing conditions. Another control system without a mechanophore shows a low fixing efficiency comparable to the HABI system. Additionally, the introduction of the BPID moiety also manifests remarkable mechanochromic behavior during the shape programing process, offering a visualizable indicator for the pre-evaluation of morphing efficiency. Unlike conventional mechanical mechanisms that simultaneously induce morphing, such as strain-induced plastic deformation or crystallization, our mechanochemical method allows for shape programming after the mechanical treatment. Our concept has potential for the design of mechanochemically programmable and mechanoresponsive shape shifting polymers.

Strain-induced recognition of molecular and chirality in cholesteric liquid crystal droplets for distance and curvature sensing.

Chirality is universal in nature and in biological systems, and the chirality of cholesteric liquid crystals (Ch-LC) is both controllable and quantifiable. Herein, a strategy for precise chirality recognition in a nematic LC host within soft microscale confined droplets is reported. This approach facilitates applications in distance and curvature sensing as well as on-site characterization of the overall uniformity and bending movements of a flexible device. Due to interfacial parallel anchoring, monodisperse Ch-LC spherical microdroplets show radial spherical structure (RSS) rings with a central radical point-defect hedgehog core. Strain-induced droplet deformation destabilizes the RSS configuration and induces the recognition of chirality, creating "core-shell" structures with distinguishable sizes and colors. In practice, an optical sensor is achieved due to the rich palette of optically active structures that can be utilized for gap distance measuring and the monitoring of curvature bending. The properties reported here and the constructed device have great potential for applications in soft robotics, wearable sensors, and advanced optoelectronic devices.

Strain-induced strengthening in superconducting β-Mo2C through high pressure and high temperature

High-strain-induced microstructural refinement and dislocations are critical for the strengthening of metallic materials; however, this is difficult to achieve in ceramic materials due to their unique bonding characteristics and electronic structure. Here, a series of β-Mo2C bulk ceramics are consolidated by the high pressure and high temperature (HPHT) strategy. Our results demonstrate that high strain-induced grain plastic deformation at high pressure produces a lamellar sub-grain structure with high-density dislocations, and that the dislocations at the lath-like grain boundaries eventually evolve into low-angle grain boundaries. The mechanical properties, superconducting behavior, and onset of oxidation of the specimens are investigated. It is found that superconductivity and hardness arise from the high density of states at the Fermi level, while the high intrinsic hardness is attributed to the strong hybridization between Mo-4d orbitals and C-2p orbitals. Furthermore, strain-induced defect structure (dislocations and low-angle grain boundaries) mainly mainly enhances the intrinsic structure of β-Mo2C.

Monolithically Programmed Stretchable Conductor by Laser-Induced Entanglement of Liquid Metal and Metallic Nanowire Backbone.

Owing to its low mechanical compliance, liquid metal is intrinsically suitable for stretchable electronics and future wearable devices. However, its invariable strain-resistance behavior according to the strain-induced geometrical deformation and the difficulty of circuit patterning limit the extensive use of liquid metal, especially for strain-insensitive wiring purposes. To overcome these limitations, herein, novel liquid-metal-based electrodes of fragmented eutectic gallium-indium alloy (EGaIn) and Ag nanowire (NW) backbone of which their entanglement is controlled by the laser-induced photothermal reaction to enable immediate and direct patterning of the stretchable electrode with spatially programmed strain-resistance characteristics are developed. The coexistence of fragmented EGaIn and AgNW backbone, that is, a biphasic metallic composite (BMC), primarily supports the uniform and durable formation of target layers on stretchable substrates. The laser-induced photothermal reaction not only promotes the adhesion between the BMC layer and substrates but also alters the structure of laser-irradiated BMC. By controlling the degree of entanglement between fragmented EGaIn and AgNW, the initial conductivity and local gauge factor are regulated and the electrode becomes effectively insensitive to applied strain. As the configuration developed in this study is compatible with both regimes of electrodes, it can open new routes for the rapid creation of complex stretchable circuitry through a single process.

Mechanical Acceleration and Control of the Thermal Motion of a Magnetic Skyrmion

Engineering the kinetic motion of magnetic skyrmions shows great potential in spintronics. Particularly, as a natural property, temperature plays a significant role in the dynamics of skyrmions. For instance, the nonlinear and the rectilinear motions of skyrmions driven by spin-transfer torque and local energy imbalance in temperature gradients, respectively, have been explored. Although existing studies have already implied the multiphysics field-controlled property of skyrmion thermal motion, the investigation of mechanically controlled skyrmion motions in temperature gradients is absent, and the kinematic equation is unclear. Here, we employ a phase-field model to simulate the effect of mechanical strain on skyrmion motion in a temperature gradient, and demonstrate that the strain-induced anisotropic deformation of skyrmions increases the driving force and accelerates their motion. To model the mechanical effect, we propose a kinematic equation for describing the relationship between skyrmion velocity and multiphysics field variables. Lastly, the potential application of the mechanically controlled skyrmion thermal motion is demonstrated via tip indentation simulations. This work provides the thermodynamic mechanism and kinematic equation for mechanically accelerated skyrmion thermal motions, which is expected to be a guidance for future research on skyrmion dynamics and application of functional devices.

Temperature dependence of tensile deformation behavior and strain hardening of lean duplex stainless steels

Two lean duplex stainless steels with different manganese contents (4 and 8 wt.%) were deformed in the tensile mode in the temperature range of 25–300 °C. The deformation-induced martensitic transformation was characterized as the main austenite deformation mechanism of 4Mn steel at room temperature. In contrast, the strain hardening behavior of 8Mn steel was regulated by the cooperation of twinning induced plasticity and transformation induced plasticity. This was justified considering the lower austenite fraction and austenite stability in 4Mn compared to the steel containing a higher manganese content. Mechanical properties such as ultimate tensile strength and uniform elongation in both steels were significantly changed as the deformation temperature was increased. Differences in chemical composition and deformation temperature led to changing deformation mode due to strain partitioning between austenite and ferrite, austenite stability, and stacking fault energy. The most important factors influencing the mechanical properties are austenite stability and stacking fault energy at elevated temperatures. It was observed that as the austenite stability increases, martensitic transformation occurs directly from austenite grain and annealing twin boundaries but does not significantly improve strength and ductility. The strain partitioning between austenite and ferrite could provide a proper condition for strain-induced martensite transformation and deformation twinning, thereby enhanced mechanical properties at elevated temperatures.

The shear strain energy fluctuations caused by random porosities in graphene based on the stochastic finite element model

Strain-induced deformation is a promising strategy to modify and functionalize the material properties of graphene. However, the impacts of random porosities are inevitable and complicated in the microstructure. In order to quantify and analyze the effects of random porosities in graphene under shear stress, the energy fluctuations and the equivalent elastic modulus are computed and recorded based on the stochastic finite element model. The finite element computation is combined with the Monte Carlo stochastic sampling procedure to distribute and propagate the random porosities in pristine graphene. Two different boundary conditions are taken into consideration and compared. Furthermore, the probability statistics of shear strain energy and equivalent elastic modulus are provided based on the comparison with the results of pristine graphene. The inhomogeneous spatial randomness is founded in the statistic records of shear strain energy. The sensitivity to the graphene chirality and boundary conditions are also shown for the porous graphene. The work in this paper provides important references for strain-induced engineering and artificial functionalization through topological vacancy control in graphene.

Elastic strain modulation of energy bandgap in β-Ga2O3 sheet: Experimental and computational investigations

Elastic strain engineering has proven to be an efficient tool to substantially modify the physical properties of semiconductors. Likewise, modification of properties by elastic strain based on 2D materials has drawn a considerable attention recently. While on ultrawide-bandgap (UWBG) materials, emergent alternatives for next-generation high-power and high-efficient electronic devices, there exist only a few experimental reports related to the strain modification of fundamental physical properties. According to the theoretical prediction, metallization and indirect-to-direct transition can be achieved in diamonds through elastic strain. In previous work, the modulation of bandgap and indirect-to-direct bandgap transition in 2D β-Ga2O3 under uniaxial strains were demonstrated. The present work reports a modified two-point bend method to apply the elastic strain to β-Ga2O3 material continuously without any damage in the crystal quality, and investigates the changes in bandgap caused by the strain-induced deformation. Free-standing β-Ga2O3 sheets exhibit a sizeable reduction in the bandgap of up to 30% (from 4.9 eV to 3.4 eV) under the bending state, as measured by X-ray photoelectron spectroscopy (XPS). Based on the predictions obtained from first-principles calculations, a strong anisotropic character in the Young's modulus of β-Ga2O3 indicates the existence of strain gradient in the free-standing β-Ga2O3 sheets under bending states, which was evinced by the confocal Raman spectroscopic measurements. Moreover, the lattice distortion caused by the strain gradient and elastic strain can be attributed to the dramatic changes in the bandgap. More importantly, in as-bent samples, the variation of bandgap was continuous and recoverable. These findings provide a direct experimental evidence of bandgap modification of β-Ga2O3 by elastic strain, and indicate a much larger and more versatile platform for the application of flexible Ga2O3 based devices to a wide range of application areas.

A simple design of mechanically robust, recyclable, and biodegradable composite films with high thermal stability and fluorescent properties

It remains a big challenge to fabricate biodegradable and recyclable soy protein (SP)-based composite films with great toughness, high strength, and large ductility. In this work, a facile strategy was proposed for preparing advanced SP-based films by simple solution casting of SP and hydroxyl and primary amine-containing hyperbranched polysiloxane (HPSA). The developed SP/HPSA2 film exhibited a high toughness of 17.63 MJ m−3 and a high tensile strength of 15.19 MPa, which was, respectively, 424.70% and 551.93% increase compared with that of the neat SP-based film. Additionally, the SP/HPSA2 film possessed a large strain at failure of 151.01%. The advanced mechanical properties can be interpreted by the toughening and reinforcing mechanism associated with the strain-induced deformation of HPSA as well as the multiple interfacial hydrogen-bonding interactions within the interphase. The composite films exhibited great recyclability due to the reversibility of non-covalent interactions confined in the matrix. Moreover, owing to the incorporation of the heat-resistant and fluorescent HPSA, the SP/HPSA films also possessed high thermal stability and great fluorescent properties. This work offers a simple methodology for the design of mechanically robust, recyclable, and biodegradable composite films, which have potential applications in the fabrication of high-performance, high-transparency, and anti-counterfeiting packaging materials.