Multifunctional UV-NIR Dual Light-Responsive Soft Actuators from a Main-Chain Azobenzene Semi-Crystalline Poly(ester-amide) Doped with Polydopamine Nanoparticles.

The development of soft photoactuators with multifunctionality and improved performance is highly important for their broad applications. Herein, we report on a facile and efficient strategy for fabricating such photoactuators with UV-NIR dual light-responsivity, room-temperature 3D shape reprogrammability and reprocessability, and photothermal healability by doping polydopamine (PDA) nanoparticles into a main-chain azobenzene semi-crystalline poly(ester-amide) (PEA). The PEA/PDA nanoparticle composite was readily processed into free-standing films with enhanced mechanical and photomechanical properties compared with the blank PEA films. Its physically crosslinked uniaxially oriented films showed rapid and highly reversible photochemically induced bending/unbending under the UV/visible light irradiation at room temperature in both the air atmosphere and water. When exposed to the NIR light, they (and their bilayer films formed with a polyimide film) exhibited photothermally induced bending even at a temperature much lower than their crystalline-to-isotropic phase transition temperature based on a unique mechanism (involving photothermally induced polymer chain relaxation due to the disruption of their hydrogen bonds). The room-temperature 3D shape reprogrammability and reprocessability and photothermal healability of the composite polymer films were also demonstrated. Such multifunctional dual light-responsive photoactuators with well-balanced mechanical robustness, actuation stability, 3D shape reprogrammability/reprocessability and photothermal healability hold much promise in various photoactuating applications.

Origin of Melt Memory Effects in Poly(ethylene oxide): The Crucial Role of Entanglements.

The melt memory effect on crystallization is an intriguing phenomenon displayed by semicrystalline polymers, as opposed to low molar mass molecules. It concerns the effect of melt temperature on nucleation upon recrystallization. Typically, polymer crystals must be considerably superheated to erase the effect of previous morphology on the subsequent crystallization, avoiding an acceleration of the process. Despite being known for decades, its origin is still not fully understood. Investigating model poly(ethylene oxide) covering a wide range of molar mass, it is demonstrated that melt memory originates from topological constraints among the chains, i.e., entanglements, for PEO in which weak intermolecular interactions are present due to the ether groups. In fact, no memory is observed for samples below the critical molar mass for the formation of entanglements (about 1 kg mol-1). The increase in molar mass raises the number of entanglements and induces the formation of folded chains crystals, both factors leading to a topologically complex amorphous phase, enhancing the melt memory effect. The molecular origin of the melt memory effect in polymers with weak intermolecular interactions is thus ascribed to a slower isotropization in the melt of the chain segments originally contained in the crystals, due to the presence of entanglements among the chains. This study defines the distinction between small molecules and polymers from the point of view of melt memory.

Entanglements of Macromolecules and Their Influence on Rheological and Mechanical Properties of Polymers.

Flexible macromolecules easily become entangled with neighboring macromolecules. The resulting network determines many polymer properties, including rheological and mechanical properties. Therefore, a number of experimental and modeling studies were performed to describe the relationship between the degree of entanglement of macromolecules and polymer properties. The introduction presents general information about the entanglements of macromolecule chains, collected on the basis of studies of equilibrium entangled polymers. It is also shown how the density of entanglements can be reduced. The second chapter presents experiments and models leading to the description of the movement of a single macromolecule. The next part of the text discusses how the rheological properties change after partial disentangling of the polymer. The results on the influence of the degree of chain entanglement on mechanical properties are presented.

Easy Synthetic Access to High-Melting Sulfurated Copolymers and their Self-Assembling Diblock Copolymers from Phenylisothiocyanate and Oxetane.

Although sulfurated polymers promise unique properties, their controlled synthesis, particularly when it comes to complex and functional architectures, remains challenging. Here, we show that the copolymerization of oxetane and phenyl isothiocyanate selectively yields polythioimidocarbonates as a new class of sulfur containing polymers, with narrow molecular weight distributions (Mn=5-80 kg/mol with D≤1.2; Mn,max=124 kg/mol) and high melting points of up to 181 °C. The method tolerates different substituent patterns on both the oxetane and the isothiocyanate. Self-nucleation experiments reveal that π-stacking of phenyl substituents, the presence of unsubstituted polymer backbones, and the kinetically controlled linkage selectivity are key factors in maximising melting points. The increased tolerance to macro-chain transfer agents and the controlled propagation allows the synthesis of double crystalline and amphiphilic diblock copolymers, which can be assembled into micellar- and worm-like structures with amorphous cores in water. In contrast, crystallization driven self-assembly in ethanol gives cylindrical micelles or platelets.

Methods for characterizing the structure of starch in relation to its applications: a comprehensive review.

Starch is a major part of the human diet and an important material for industrial utilization. The structure of starch granules is the subject of intensive research because it determines functionality, and hence suitability for specific applications. Starch granules are made up of a hierarchy of complex structural elements, from lamellae and amorphous regions to blocklets, growth rings and granules, which increase in scale from nanometers to microns. The complexity of these native structures changes with the processing of starch-rich ingredients into foods and other products. This review aims to provide a comprehensive review of analytical methods developed to characterize structure of starch granules, and their applications in analyzing the changes in starch structure as a result of processing, with particular consideration of the poorly understood short-range ordered structures in amorphous regions of granules.

Teaching Old Polymers New Tricks: Improved Synthesis and Anomalous Crystallinity for a Lost Semi-Fluorinated Polyaryl Ether via Interfacial Polymerization of Hexafluoroacetone Hydrate and Diphenyl Ether.

A practical and direct electrophilic polymerization of hexafluoroacetone hydrate with diphenyl ether toward the preparation of semi-fluorinated polyaryl ethers (PAE) is reported. Electrophilic aromatic substitution (EAS) polymerization under interfacial conditions with phase transfer catalyst (Aliquat 336) proceeds in trifluoromethanesulfonic anhydride by generation of trifluoromethanesulfonic acid and the protonated hexafluoroacetone (HFA) in situ affording 1,1,1,3,3,3-hexafluoroisopropylidene (6F) PAE with high regioselectivity (4,4'-DPE) and high molecular weight (≈60 kDa). Although first reported in a 1966 US Patent by DuPont using harsh conditions, improved synthetic methods or modern characterization has not been disclosed until now. Despite the presence of the 6F group, known to impart disordered morphology, this simple semi-fluorinated PAE exhibits anomalous crystallinity with polymorphic melting points (Tm ) ranging from 230-309 °C, high solubility in common organic solvents, a glass transition (Tg ) of 163 °C, and thermo-oxidative stability above 500 °C. Tough optically clear films prepared from solution give transmittance higher than 90% throughout the visible region. Synthesis, mechanistic aspects, and characterization including surface and dielectric properties are discussed.

Rheological Characterization of Molten Polymer-Drug Dispersions as a Predictive Tool for Pharmaceutical Hot-Melt Extrusion Processability.

PURPOSE: The aim of this study was to investigate (i) the influence of drug solid-state (crystalline or dissolved in the polymer matrix) on the melt viscosity and (ii) the influence of the drug concentration, temperature and shear rate on polymer crystallization using rheological tests. METHODS: Poly (ethylene oxide) (PEO) (100.000 g/mol) and physical mixtures (PM) containing 10-20-30-40% (w/w) ketoprofen or 10% (w/w) theophylline in PEO were rheologically characterized. Rheological tests were performed (frequency and temperature sweeps in oscillatory shear as well as shear-induced crystallization experiments) to obtain a thorough understanding of the flow behaviour and crystallization of PEO-drug dispersions. RESULTS: Theophylline did not dissolve in PEO as the complex viscosity (η*) of the drug-polymer mixture increased as compared to that of neat PEO. In contrast, ketoprofen dissolved in PEO and acted as a plasticizer, decreasing η*. Acting as a nucleating agent, theophylline induced the crystallization of PEO upon cooling from the melt. On the other hand, ketoprofen inhibited crystallization upon cooling. Moreover, higher concentrations of ketoprofen in the drug-polymer mixture increasingly inhibited polymer crystallization. However, shear-induced crystallization was observed for all tested mixtures containing ketoprofen. CONCLUSION: The obtained rheological results are relevant for understanding and predicting HME processability (e.g., barrel temperature selection) and downstream processing such as injection moulding (e.g., mold temperature selection).

Dynamic development of changes in multi-scale structure during grain filling affect gelatinization properties of rice starch.

Rice was collected over the entire grain filling period (about 40 days) to explore the multi-structure evolution and gelatinization behavior changes of starch. During the early stage (DAA 6-14), the significant reduction in lamellar repeat distance (10.04 to 9.68 nm) and relative crystallinity (26.6 % to 22.7 %) was due to initial rapid accumulation of amylose (from 9.38 % to 14.05 %) and short amylopectin chains. Meanwhile, the decreased proportion of aggregation structure resulted in a decrease in the gelatinization temperature and a narrowed range of gelatinization temperature also indicated an increase in homogeneity as starch matured. Gelatinization enthalpy was mainly controlled by aggregation structure, which was negatively and positively related to the amylose content and the degree of order respectively. Peak viscosity of starch pasting increased and reached a maximum (924 cP) at DAA-21 due to larger granule size. Amylose and short amylopectin chains with degree of polymerization 6-12 showed positive and negative correlation with short-term retrogradation ability (setback value) respectively. The dynamics of different scale structure during grain filling had varying degrees of impact on gelatinization properties.

Quality assessment of the wide-angle detection option planned at the high-intensity/extended Q-range SANS diffractometer KWS-2 combining experiments and McStas simulations.

For a reliable characterization of materials and systems featuring multiple structural levels, a broad length scale from a few ångström to hundreds of nanometres must be analyzed and an extended Q range must be covered in X-ray and neutron scattering experiments. For certain samples or effects, it is advantageous to perform such characterization with a single instrument. Neutrons offer the unique advantage of contrast variation and matching by D-labeling, which is of great value in the characterization of natural or synthetic polymers. Some time-of-flight small-angle neutron scattering (TOF-SANS) instruments at neutron spallation sources can cover an extended Q range by using a broad wavelength band and a multitude of detectors. The detectors are arranged to cover a wide range of scattering angles with a resolution that allows both large-scale morphology and crystalline structure to be resolved simultaneously. However, for such analyses, the SANS instruments at steady-state sources operating in conventional monochromatic pinhole mode rely on additional wide-angle neutron scattering (WANS) detectors. The resolution must be tuned via a system of choppers and a TOF data acquisition option to reliably measure the atomic to mesoscale structures. The KWS-2 SANS diffractometer at Jülich Centre for Neutron Science allows the exploration of a wide Q range using conventional pinhole and lens focusing modes and an adjustable resolution Δλ/λ between 2 and 20%. This is achieved through the use of a versatile mechanical velocity selector combined with a variable slit opening and rotation frequency chopper. The installation of WANS detectors planned on the instrument required a detailed analysis of the quality of the data measured over a wide angular range with variable resolution. This article presents an assessment of the WANS performance by comparison with a McStas [Willendrup, Farhi & Lefmann (2004). Physica B, 350, E735-E737] simulation of ideal experimental conditions at the instrument.

Coarse-Grained Simulations on Polyethylene Crystal Network Formation and Microstructure Analysis.

Understanding and characterizing semi-crystalline models with crystalline and amorphous segments is crucial for industrial applications. A coarse-grained molecular dynamics (CGMD) simulations study probed the crystal network formation in high-density polyethylene (HDPE) from melt, and shed light on tensile properties for microstructure analysis. Modified Paul-Yoon-Smith (PYS/R) forcefield parameters are used to compute the interatomic forces among the PE chains. The isothermal crystallization at 300 K and 1 atm predicts the multi-nucleus crystal growth; moreover, the lamellar crystal stems and amorphous region are alternatively oriented. A one-dimensional density distribution along the alternative lamellar stems further confirms the ordering of the lamellar-stack orientation. Using this plastic model preparation approach, the semi-crystalline model density (ρcr) of ca. 0.913 g·cm-3 and amorphous model density (ρam) of ca. 0.856 g·cm-3 are obtained. Furthermore, the ratio of ρcr/ρam ≈ 1.06 is in good agreement with computational (≈1.096) and experimental (≈1.14) data, ensuring the reliability of the simulations. The degree of crystallinity (χc) of the model is ca. 52% at 300 K. Nevertheless, there is a gradual increase in crystallinity over the specified time, indicating the alignment of the lamellar stems during crystallization. The characteristic stress-strain curve mimicking tensile tests along the z-axis orientation exhibits a reversible sharp elastic regime, tensile strength at yield ca. 100 MPa, and a non-reversible tensile strength at break of 350%. The cavitation mechanism embraces the alignment of lamellar stems along the deformation axis. The study highlights an explanatory model of crystal network formation for the PE model using a PYS/R forcefield, and it produces a microstructure with ordered lamellar and amorphous segments with robust mechanical properties, which aids in predicting the microstructure-mechanical property relationships in plastics under applied forces.

Endowing Polythioester Vitrimer with Intrinsic Crystallinity and Chemical Recyclability.

Technologically important thermosets face a long-standing end-of-life (EoL) problem of non-reprocessability, a more sustainable solution of which has resolved to nascent vitrimers that can merge the robust material properties of thermosets and the reprocessability of thermoplastics. However, the lifecycle of vitrimers is still finite, as they often suffer from significant deterioration of mechanical performance following multiple reprocessing cycles, analogous to mechanical recycling, and they often show undesired creep under working conditions. To address these two key limitations, we have developed a cross-linked semi-crystalline polythioester with both dynamic covalent bonds and intrinsic crystallinity and chemical recyclability, affording a vitrimeric system that exhibits not only reprocessability and crystallinity-restricted creep but also complete chemical recyclability to initial monomer by catalyzed depolymerization in solution or bulk. Therefore, reported herein is an "infinite" vitrimer system that is empowered with a facile closed-loop EoL option once serial reprocessing deteriorates performance and the material can no longer meet the application requirements. Specifically, the polythioester vitrimer was constructed by copolymerization of a bicyclic thioester with a bis-dithiolane, producing dynamically cross-linked polythioesters with excellent property tunability, from amorphous to semi-crystalline states and melting transition temperatures from 91 to 178 °C.

The alterations in granule, shell, blocklets, and molecular structure of pea starch induced by ultrasound.

Understanding the alterations to starch multi-scale structure induced by ultrasound treatment can help in determining the effective application of ultrasound in functional-starch preparation. This study aimed to comprehensively characterize and understand the morphological, shell, lamellae, and molecular structures of pea starch granules treated by ultrasound under different temperatures. Scanning electron microscopy and X-ray diffraction analyses showed that UT (ultrasound treatment) did not change C-type of crystalline, but caused a pitted surface and endowed a looser structure and higher enzyme susceptibility as the temperature increased above 35 °C for pea starch granules. Fourier transform infrared spectroscopy and small-angle X-ray scattering analyses revealed that UT reduced the short-range ordering and increased the thickness of semi-crystalline and amorphous lamellae by inducing starch chain depolymerization, which was manifested by molecule weight and chain length distribution analysis. The sample ultrasound-treated at 45 °C had the higher proportion of B2 chains compared with the other ultrasound-treated samples because the higher ultrasonic temperature altered the disruption sites of starch chains.

Analysis of the Structure and the Thermal Conductivity of Semi-Crystalline Polyetheretherketone/Boron Nitride Sheet Composites Using All-Atom Molecular Dynamics Simulation.

Thermal transport simulations were performed to investigate the important factors affecting the thermal conductivity based on the structure of semi-crystalline polyetheretherketone (PEEK), and the addition of boron nitride (BN) sheets. The molecular-level structural analysis facilitated the prediction of the thermal conductivity of the optimal structure of PEEK reflecting the best parameter value of the length of amorphous chains, and the ratio of linkage conformations, such as loops, tails, and bridges. It was found that the long heat transfer paths of polymer chains were induced by the addition of BN sheets, which led to the improvement of the thermal conductivities of the PEEK/BN composites. In addition, the convergence of the thermal conductivities of the PEEK/BN composites in relation to BN sheet size was verified by the disconnection of the heat transfer path due to aggregation of the BN sheets.

Semi-crystalline sulfonated poly(ether ketone) proton exchange membranes: The trade-off of facile synthesis and performance.

Improving the performance of proton exchange membranes (PEMs) through the synthesis of sulfonated polymers with elaborate molecular structures has received extensive approval. However, the tedious synthetic process and consequently high costs restrain their possible substitution for Nafion, a classic PEM material. Herein, a series of semi-crystalline sulfonated poly(ether ketone)s with fluorene-based units were prepared via direct copolymerization of commercially available monomers and followed post-sulfonation, namely SPEK-FD-x, where × represents the molar ratio of the fluorene-containing monomer to the employed bisphenol monomers. The entire synthetic pathway was facile without involving hardly accessible materials. Subsequently, various properties of SPEK-FD-x membranes were investigated and further compared with Nafion 117. Due to the formation of the well-defined hydrophilic-hydrophobic microphase separation morphology and the reinforcement of the PEK crystalline regions, the SPEK-FD-x membranes exhibited outstanding proton conductivity, resistance for methanol permeation, as well as dimensional, thermal, oxidative, and mechanical stability. Among them, the overall behavior of the SPEK-FD-25 membrane was comparable to or even greater than that of Nafion 117, most importantly, it also performed decently in both H2/air fuel cells and direct methanol fuel cells. Therefore, with the straightforward synthesis and superior performance, the SPEK-FD-x membranes may serve as a promising alternative to Nafion.

Hot Melt Extruded Posaconazole-Based Amorphous Solid Dispersions-The Effect of Different Types of Polymers.

Four model polymers, representing (i) amorphous homopolymers (Kollidon K30, K30), (ii) amorphous heteropolymers (Kollidon VA64, KVA), (iii) semi-crystalline homopolymers (Parteck MXP, PXP), and (iv) semi-crystalline heteropolymers (Kollicoat IR, KIR), were examined for their effectiveness in creating posaconazole-based amorphous solid dispersions (ASDs). Posaconazole (POS) is a triazole antifungal drug that has activity against Candida and Aspergillus species, belonging to class II of the biopharmaceutics classification system (BCS). This means that this active pharmaceutical ingredient (API) is characterized by solubility-limited bioavailability. Thus, one of the aims of its formulation as an ASD was to improve its aqueous solubility. Investigations were performed into how polymers affected the following characteristics: melting point depression of the API, miscibility and homogeneity with POS, improvement of the amorphous API's physical stability, melt viscosity (and associated with it, drug loading), extrudability, API content in the extrudate, long term physical stability of the amorphous POS in the binary drug-polymer system (in the form of the extrudate), solubility, and dissolution rate of hot melt extrusion (HME) systems. The obtained results led us to conclude that the physical stability of the POS-based system increases with the increasing amorphousness of the employed excipient. Copolymers, compared to homopolymers, display greater homogeneity of the investigated composition. However, the enhancement in aqueous solubility was significantly higher after utilizing the homopolymeric, compared to the copolymeric, excipients. Considering all of the investigated parameters, the most effective additive in the formation of a POS-based ASD is an amorphous homopolymer-K30.

Determining weathering-induced heterogeneous oxidation profiles of polyethylene, polypropylene and polystyrene using laser-induced breakdown spectroscopy.

Weathering-induced polymer degradation is typically heterogeneous which plays an integral part in fragmentation. Despite that, the current selection of techniques to investigate such heterogeneities, especially beneath the sample surface, is sparse. We introduce Laser-induced Breakdown Spectroscopy (LIBS) as an analytical tool and evaluate its performance for depth profiling. Three types of polymers were selected (polyethylene, polypropylene, and polystyrene) that were aged under controlled conditions. We demonstrate that LIBS can detect heterogeneous oxidation on the surface and inside the samples. The results reveal that different oxidation behaviors are linked to the sample's lattice structure and the subsequent formation of microcracks. This implies that LIBS is beneficial to give additional insights into the weathering and degradation behavior of environmentally relevant plastics.

Predicting self-diffusion coefficients in semi-crystalline and amorphous solid dispersions using free volume theory.

The self-diffusion coefficient of active ingredients (AI) in polymeric solid dispersions is one of the essential parameters for the rational formulation design in life sciences. Measuring this parameter for products in their application temperature range can, however, be difficult to realise and time-consuming (due to the slow kinetics of diffusion). The aim of this study is to present a simple and time-saving platform for predicting the AI self-diffusivity in amorphous and semi-crystalline polymers on the basis of a modified version of Vrentas' and Duda's free volume theory (FVT) [A. Mansuri, M. Völkel, T. Feuerbach, J. Winck, A.W.P. Vermeer, W. Hoheisel, M. Thommes, Modified free volume theory for self-diffusion of small molecules in amorphous polymers, Macromolecules. (2023)]. The predictive model discussed in this work requires pure-component properties as its input and covers the approximate temperature range of T < 1.2 Tg, the whole compositional range of the binary mixtures (as long as a molecular mixture is present), and the whole crystallinity range of the polymer. In this context, the self-diffusion coefficients of the AIs imidacloprid, indomethacin, and deltamethrin were predicted in polyvinylpyrrolidone, polyvinylpyrrolidone/vinyl acetate, polystyrene, polyethylene, and polypropylene. The results highlight the profound importance of the kinetic fragility of the solid dispersion on the molecular migration; a property which in some cases might entail higher self-diffusion coefficients despite an increase in the molecular weight of the polymer. We interpret this observation within the context of the theory of heterogeneous dynamics in glass-formers [M.D. Ediger, Spatially heterogeneous dynamics in supercooled liquids, Annu. Rev. Phys. Chem. 51 (2000) 99-128] by attributing it to the stronger presence of "fluid-like" mobile regions in fragile polymers offering facilitated routes for the AI diffusion within the dispersion. The modified FVT further allows for identifying the influence of some structural and thermophysical material properties on the translational mobility of AIs in binary dispersions with polymers. In addition, estimates of self-diffusivity in semi-crystalline polymers are provided by further accounting for the tortuosity of the diffusion paths and the chain immobilisation at the interface of the amorphous and crystalline phases.

Structural and physicochemical characteristics of wheat starch as influenced by freeze-thawed cycles and antifreeze protein from Sabina chinensis (Linn.) Ant. cv. Kaizuca leaves.

The effects of freeze-thawed cycles (FTs) and a new antifreeze protein from Sabina chinensis (Linn.) Ant. cv. Kaizuca leaves (ScAFP) on the structure and physicochemical characteristics of wheat starch were studied. The mechanical breaking exerted by ice crystals on starch granules during FTs gradually deepened, sequentially squeezing the surface (2-6 FTs), amorphous region (8 FTs) and crystalline region (10 FTs) of starch granules. These changes led to reduced thermal stability, increased retrogradation tendency, and weakened gel network structure. The addition of ScAFP retarded the damage of ice crystals on starch granule structure and crystal structure during FTs, and significantly reduced the retrogradation tendency. Compared with native starch, the hardness of freeze-thawed starch without and with added ScAFP after 10 FTs decreased by 17.85% and 9.22%, respectively, indicating ScAFP improved the gel texture properties of freeze-thawed starch. This study provides new strategies for improving the quality of frozen starch-based foods.

On the Proton Conduction Pathways in Polyelectrolyte Membranes Based on Syndiotactic-Polystyrene.

When functionalized by the solid-state sulfonation process, the amorphous regions of the semi-crystalline syndiotactic-polystyrene (sPS) become hydrophilic, and thus can conduct protons upon membrane hydration, which increases the interest in this material as a potential candidate for applications with proton exchange membranes. The resistance of sulfonated sPS to oxidative decomposition can be improved by doping the membrane with fullerenes. In previous work, we have described the morphology in hydrated sulfonated sPS films doped with fullerenes on different length scales as determined by small-angle neutron scattering (SANS) and the structural changes in such membranes as a function of the degree of hydration and temperature. In the current work, we report on the relationship between the morphology of hydrated domains as obtained by SANS and the proton conductivity in sulfonated sPS-fullerene composite membranes at different temperature and relative humidity (RH) conditions. Based on this combined experimental approach, clear evidence for the formation and evolution of the hydrated domains in functionalized sPS membranes has been provided and a better understanding of the hydration and conductivity pathways in this material has been obtained.

Formation and structure evolution of starch nanoplatelets by deep eutectic solvent of choline chloride/oxalic acid dihydrate treatment.

In this study, we report a top-down approach to fabricate starch nanoplatelets (SNPs) based on a deep eutectic solvent (DES) comprised of choline chloride and oxalic acid dihydrate. When subjecting waxy maize starch (WMS) to 2 h of DES treatment, the SNPs of oxalate half-ester were successfully fabricated. The formation mechanism of SNPs was studied by monitoring the changes in nanoplatelet morphology, amylopectin chain distribution, long-range crystallinity, and semi-crystalline lamellar structure of the DES-treated WMS at various treatment times. During the DES treatment, relative crystallinity values of WMS gradually decreased from 28.7 to 25.2%. With increasing DES treatment time from 0 to 1.5 h, the thickness of crystalline lamellae decreased from 6.38 to 5.57 nm, whereas the opposite trend was observed for the thickness of amorphous lamellae. The method developed in this work offers a green and efficient route to prepare non-toxic starch nanomaterials.