Low Enthalpy Research Articles

PVA-assisted graphene aerogels composite phase change materials with anisotropic porous structure for thermal management

The rapid development of spacecraft thermal control systems necessitates high-performance phase change materials (PCMs) with low density, high thermal conductivity and high enthalpy. Graphene aerogels (GAs) prepared by unidirectional freezing are ideal candidates as thermal conductive networks for PCMs due to the anisotropic porous structures. However, constructing anisotropic thermal conductive composite PCMs with low graphene aerogel loading while employing environmentally friendly cross-linking agents remains challenging. To fulfill the research gap, this study explores the synthesis of poly(vinyl alcohol) (PVA)/graphene aerogels (PGAs) by hydrothermal reaction and conventional freeze-drying. Anisotropic PGAs with oriented porous structures were fabricated by unidirectional freezing. After annealing and impregnation with paraffin wax, composite PCMs with excellent shape stability were obtained. The prepared composite exhibits low density (0.82 g cm−3) and high enthalpy (165 J g−1). The combination of PVA and graphene enables the composite to achieve an ultralow graphene aerogel loading (0.85 wt%) while maintaining high thermal conductivity (1.37 W m−1 K−1), leading to a high specific thermal conductivity enhancement up to 477. This work sheds light on the potential of combing PVA and graphene to construct thermal conductive aerogels, intending to provide feasible means to develop high-performance PCMs for spacecraft thermal management.

Biomimetically spider web-like hydrogels for high-efficiency solar evaporators

With the increasing population, the shortage of freshwater resources has become a problem faced by human beings. Although many hydrogel solar evaporators achieved high evaporation rates by increasing the intermediate water content to reduce the enthalpy of water evaporation, it is still challenging to explore effective photothermal materials to construct efficient hydrogel solar evaporators. Here, inspired by the spider web structure, interconnected porous hydrogels were proposed by cross-linking heterojunctions and polymers. For the first time, MXene heterojunction is applied to solar evaporators. The introduction of SnS2 greatly improves the light absorption of MXene, at the same time, benefiting from the multi-scale macro/micro fiber network structure, MXene-SnS2 hydrogel (MSH) has a good “lock-in” performance, which makes the heat locally distributed near the evaporable water. As a result, the MSH evaporator has a low enthalpy of evaporation, with an evaporation rate of 3.3606 kg m−2 h−1 in 3.5 wt% salt water, and can maintain 1.9 kg m−2 h−1 even in 10.5 % brine. The evaporators present superior purification performance for seawater, could maintain high and stable evaporation performance for 72 h. This design principle and excellent performance provide a potential method and design concept for seawater desalination.

Effect of carboxymethyl cellulose binder on physical, thermal, and rheological properties of milk protein isolate/guar gum mixture powder

This study examined the effect of fluidized-bed agglomeration with a carboxymethyl cellulose (CMC) binder on the physical, thermal, and rheological properties of agglomerated milk protein isolate (MPI)-guar gum (GG) mixtures (AMGs). The agglomeration process produced larger and more porous particles, improving solubility and powder flowability. An exothermic event followed by an endothermic event was observed in DSC thermograms. These thermal events tended to occur at a higher temperature with lower enthalpy values as the binder concentration increased. All samples exhibited shear-thinning behavior, with apparent viscosity at 100 s−1 values (0.27–0.29 Pa s) for AMGs being lower than for non-agglomerated MPI-GG mixture (NAMG; 0.34 Pa s). Viscoelastic moduli values showed similar trends. Additionally, compared to NAMG, larger and more guar gum lumps occurred in the AMGs. These findings suggest that the agglomeration process with CMC promoted depletion interactions between the protein and polysaccharide components in the mixture system.

Experimental study on the performance of the vertical shell-tube indirect evaporative cooler with inner grooved tubes

The vertical tube indirect evaporative cooler (VTIEC) could be preferred one to air-conditioning buildings if its water film quality could be improved. This paper proposed a new VTIEC with inner grooved tubes to improve the water film quality and obtained its performance by experimental method. The results indicated that inner grooved tubes have positive effects on the water film and performance of the new VTIEC. A low working air enthalpy at inlet can significantly improve the total cooling capacity from evaporation, and then VTIEC performance. In this paper conditions, the velocity ratio of 1.52 of the produced air to the working air is better one condition compared to 1.01 and 2.28. The produced air velocity is positive effect on the cooling capacity per unit area until the produced air velocity of about 4.05 m/s and is negative effect on COP. The maximum unit cooling capacity, wet-bulb efficiency and COP are 307.74W/m2, 81.7% and 44.97.The results will promote the application of the new VTIEC.

A Computational Analysis of the Proton Affinity and the Hydration of TEMPO and Its Piperidine Analogs.

The study investigated the impact of protonation and hydration on the geometry of nitroxide radicals using B3LYP and M06-2X methods. Results indicated that TEMPO exhibited the highest proton affinity in comparison to TEMPOL and TEMPONE. Two pathways contribute to hydrated protonated molecules. TEMPO shows lower first enthalpies of hydration (ΔH1-M), indicating stronger H-bonding interactions, while TEMPONE shows higher values, indicating weaker interactions with H2O. Solvent effects affect charge distribution by decreasing their atomic charge. Spin density (SD) is primarily concentrated in the NO segment, with minimal water molecule contamination. Protonation increases SD on N-atom, while hydration causes a more pronounced redistribution for water molecules. The stability of the dipolar structure (>N·+-O-) is evident in SD redistributions. The frontier molecular orbital (FMO) analysis of TEMPONE reveals a minimum EHOMO-LUMO gap (EH-L), enhancing the piperidine ring's reactivity. TEMPO is the most nucleophilic species, while TEMPONE exhibits strong electrophilicity. Transitioning from NO radicals to protonated forms increases the EH-L gap, indicating protonation stabilizes FMOs. Increased water molecules make the molecule less reactive, while increasing hydration decreases this energy gap, making the molecule more reactive. A smaller EH-L gap indicates the compound becomes softer and more prone to electron density and reactivity changes.

Effect of soaking in plasma-activated liquids (PALs) on heavy metals and other physicochemical properties of contaminated rice

In this study, plasma-activated liquids (PALs) were produced by a cold plasma gliding arc device at two different exposure times (7.5 and 15 min) and compared with deionized water (DW) as a control. The results showed that the amount of arsenic (As: 98 %), cadmium (Cd: 93 %), and lead (Pb: 93.3 %) were significantly decreased in all samples after soaking in PALs and DW than raw rice (p < 0.05). However, 15-min PALs were more successful. All soaked samples did not exceed the maximum residue limits (MRLs). A softer and easier chewing texture was observed for rice samples soaked in PALs than the sample soaked in DW. The samples treated with PALs also showed a lower gelatinization temperature and enthalpy. The color parameters and microstructure of rice samples were affected by treatment with PALs. Therefore, soaking rice in PALs before cooking can be considered an effective method to reduce the heavy metals in rice.

Asymmetrical Modification of Cyclopentadienyl Cobalt in Eu-MOF for C2H2/CO2 Separation.

The development of novel adsorption materials is of significance for the efficient and low-energy purification of acetylene (C2H2). Emerging metal-organic framework (MOF) adsorbents demonstrate great application prospects in the field of gas adsorption and separation. Herein, we synthesized a Eu-MOF asymmetrically modified with cyclopentadienyl cobalt exhibiting two different types of cages, denoted as UPC-119. Adsorption isotherms and dynamic breakthrough curves confirm its potential in C2H2/CO2 separation, which is further evidenced by theoretical simulations. The high adsorption capacity and low adsorption enthalpy render UPC-119 as a promising adsorbent for C2H2/CO2 separation with ease of regeneration.

Effects of Microwave Treatment on Physicochemical Attributes, Structural Analysis, and Digestive Characteristics of Pea Starch-Tea Polyphenol Complexes.

Addressing the challenge of blood glucose fluctuations triggered by the ingestion of pea starch, we have adopted an eco-friendly strategy utilizing microwave irradiation to synthesize the novel pea starch-tea polyphenol complexes. These complexes exhibit high swelling capacity and low solubility, and their thermal profile with low gelatinization temperature and enthalpy indicates adaptability to various processing conditions. In vitro digestion studies showed that these complexes have a small amount of rapidly digestible starch and a large amount of resistant starch, leading to a slower digestion rate. These features are particularly advantageous for diabetics, mitigating glycemic excursions. Structurally, the pea starch-tea polyphenol complexes exhibited a B + V-shaped dense network with low crystallinity, high orderliness, and a prominent double helix content, enhancing its stability and functionality in food applications. In summary, these innovative complexes served as a robust platform for developing low glycemic index foods, catering to the nutritional needs of diabetics. It offers an environmentally sustainable approach to food processing, fostering human well-being and propelling innovation in the food industry.

Halotolerant Microorganism-Based Soil Conditioner Application Improved the Soil Properties, Yield, Quality and Starch Characteristics of Hybrid Rice under Higher Saline Conditions.

Soil salinity represents a significant factor affecting agricultural productivity and crop quality. The present study was conducted to investigate the effects of soil conditioner (SC) comprising halotolerant microorganisms on the soil fertility, yield, rice quality, and the physicochemical and structural properties of starch in hybrid rice under saline conditions. The experimental treatments were composed of two high-quality hybrid rice varieties, i.e., 'Y Liangyou 957' (YLY957) and Jing Liangyou 534 (JLY534), and two soil amendment treatments, i.e., the application of SC at control levels and 2250 kg hm-2, or 'CK and SC', respectively. The crop was subjected to a mixture of fresh and sea water (EC 11 dS/m). The results demonstrated that the application of SC significantly enhanced the rice yield under salt stress conditions owing to an increase in the number of grains per panicle. Furthermore, SC was found to be effective in improving the organic matter and soil nutrient content. Furthermore, the application of SC resulted in an improvement in antioxidant defense, higher leaf SPAD values, and greater crop biomass, as well as the translocation of photo-assimilates at the heading stage. The application of SC not only improved the milling and appearance quality but also enhanced the taste value of rice by increasing the amylose and reducing the protein content. Furthermore, the application of SC also decreased the indentations on the surfaces of starch granules and cracks on the edges of the granules. The rice varieties subjected to SC exhibited excellent pasting properties, characterized by reduced proportions of amylopectin short chains and a lower gelatinization temperature and enthalpy of gelatinization. Overall, these findings serve to reinforce the efficacy of soil conditioner as a valuable tool to improve rice productivity and sustainability with improved rice grain quality under saline conditions.

Hierarchical porous structure design and water activation in hydrogels containing hyperbranched peach gum polysaccharide for efficient solar water evaporation

Solar-powered interfacial evaporation is a developing and sustainable technique increasingly utilized in desalination and wastewater purification. This technology involves the creation of cellulose nanofiber (CNF)/polylactic acid (PLA) composite aerogels through the Pickering emulsion approach. Self-floating aero-hydrogel (E-VGP) with a hierarchical porous structure was formed on a viscous mixture containing polyvinyl alcohol (PVA), peach gum polysaccharide (PGP), and polypyrrole (PPy) via an in-situ polymerization process. Furthermore, by modifying the hydrolysis time of PGP with a hyperbranched polyhydroxy structure, VGP hybrid hydrogels of varying microscopic molecular sizes were produced. Additionally, solar vapor generators (SVG) with diverse macroscopic structures were fabricated using molds. The V8G4-12hP0.2 hybrid hydrogel, synthesized using PGP hydrolyzed for 12 h, exhibited an evaporation enthalpy of water at 1204 J g−1. This capacity effectively activates water and enables low enthalpy evaporation. Conversely, the macrostructural design allows the cylindrical rod raised sundial-shaped structure of SVG3 to possess an expanded evaporation area, minimize energy loss, and even harness additional energy from its nonradiative side. Consequently, this micro-macrostructural design enables SVG3 to attain an exceptionally high evaporation rate of 3.13 kg m−2 h−1 under 1 Sun exposure. Moreover, SVG3 demonstrates robust water purification abilities, suggesting significant potential for application in both desalination and industrial wastewater treatment.

Optimal condition design of cannabis drying for vacuum heat pump dryer using computational fluid dynamic method interaction with heat transfer

Utilizing low temperatures and short drying cycles, the vacuum heat pump dryer (VHPD) is ideal for cannabis drying due to the plant's sensitivity to heat and light. To achieve uniform drying and maintain cannabis quality, it is essential to design the dryer with an efficient temperature distribution throughout the drying chamber. CFD models are developed in this study to simulate various scenarios within the VHPD system. The optimization of pressure and temperature is carried out using a systematic approach with the Latin Hypercube Sampling experimental design. This method generates twenty pairs of values for the pressure and temperature variables, confined to ranges of 20–40 kPa and 30–45 °C, respectively. To confirm the simulation results, an experimental study is performed using a VHPD designed from insights gained through a detailed CFD analysis. The conditions of 20.2 kPa at 31.6 °C are considered optimal due to their more uniform temperature distribution and lower static enthalpy relative to other conditions. The temperature in the upper chamber is maintained slightly lower, within the range of 30.5–31.5 °C. Furthermore, the airflow distribution demonstrates uniform movement within the central region of the chamber, with velocities ranging from 2.5 to 3.5 m/s. The simulated temperature results demonstrated a strong correlation with a temperature difference in the range of 0–0.05 °C, evidenced by an RMSE of 0.0191. The VHPD successfully dries 18 kg of fresh cannabis in 180 min, reaching the desired moisture content range of 10–14 % on a dry basis.

Novel differential scanning calorimetry (DSC) application to select polyhydroxyalkanoate (PHA) producers correlating 3-hydroxyhexanoate (3-HHx) monomer with melting enthalpy.

Polyhydroxyalkanoate (PHA) is an environmental alternative to petroleum-based plastics because of its biodegradability. The polymer properties of PHA have been improved by the incorporation of different monomers. Traditionally, the monomer composition of PHA has been analyzed using gas chromatography (GC) and nuclear magnetic resonance (NMR), providing accurate monomer composition. However, sequential analysis of the thermal properties of PHA using differential scanning calorimetry (DSC) remains necessary, providing crucial insights into its thermal characteristics. To shorten the monomer composition and thermal property analysis, we directly applied DSC to the analysis of the obtained PHA film and observed a high correlation (r2 = 0.98) between melting enthalpy and the 3-hydroxyhexanoate (3-HHx) mole fraction in the polymer. A higher 3-HHx fraction resulted in a lower melting enthalpy as 3-HHx provided the polymer with higher flexibility. Based on this, we selected the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) producing strain from Cupriavidus strains that newly screened and transformed with vectors containing P(3HB-co-3HHx) biosynthetic genes, achieving an average error rate below 1.8% between GC and DSC results. Cupriavidus sp. BK2 showed a high 3-HHx mole fraction, up to 10.38mol%, with Tm(℃) = 171.5 and ΔH of Tm (J/g) = 48.0, simultaneously detected via DSC. This study is an example of the expansion of DSC for PHA analysis from polymer science to microbial engineering.

Double-network aerogel-based eutectic composite phase change materials for efficient solar energy storage and building thermal management

Phase change materials (PCMs) have shown great promise in solar energy storage and thermal management of buildings. Nevertheless, the solid-liquid PCMs currently used in these applications face multiple challenges that need to be addressed, such as inadequate solar absorption capacity, leakage issues, and low phase change enthalpy. In this research, urea and sodium acetate trihydrate (SAT) were employed as the main PCMs, while disodium hydrogen phosphate dodecahydrate (DHPD) served as the nucleating agent. Additionally, we used polyvinyl alcohol/silica (PVA/SiO2) aerogel as a porous support structure. Carbon nanotubes (CNTs) were also introduced as photothermal conversion materials to fabricate a photothermal conversion-type double-network aerogel-based eutectic composite PCM (ECPCM). The prepared ECPCM exhibited excellent shape stability, high mechanical strength, and outstanding photothermal conversion performance. Moreover, the ECPCM demonstrated good flame retardancy, low supercooling, and the absence of phase separation issues. Furthermore, the ECPCM demonstrated efficient solar energy storage capacity and outstanding performance in building thermal management. This study offers a new perspective on the advancement of ECPCMs in solar energy storage and thermal management of buildings.

Simultaneous Solar‐Driven Interfacial Evaporation and Photo‐Fenton Oxidation by Semiconducting Metal–Organic Framework From Waste Polyimide

The integrated technology of interfacial solar steam generation and photo‐Fenton oxidation has emerged as a promising way to simultaneously mitigate freshwater scarcity and degrade organic pollutants. However, fabricating low‐cost, multi‐functional evaporators with high water evaporation and catalytic ability still presents a significant challenge. Herein, we report the functional upcycling of waste polyimide into semiconducting Fe‐BTEC and subsequently construct Fe‐BTEC‐based composite evaporators for simultaneous freshwater production and photo‐Fenton degradation of pollutants. Firstly, through a two‐step solvothermal‐solution stirring method, Fe‐BTEC nanoparticles with the size of 20–100 nm are massively produced from waste polyimide, with a band gap energy of 2.2 eV. The composite evaporator based on Fe‐BTEC and graphene possesses wide solar‐spectrum absorption capacity, high photothermal conversion capacity, rapid delivery of water, and low enthalpy of evaporation. Benefiting from the merits above, the composite evaporator achieves a high evaporation rate of 2.72 kg m−2 h−1 from tetracycline solution, as well as the photothermal conversion efficiency of 97% when exposed to irradiation of 1 Sun, superior to many evaporators. What is more, the evaporator exhibits the tetracycline degradation rate of 99.6% with good recycling stability, ranking as one of the most powerful heterogeneous Fenton catalysts. COMSOL Multiphysics and density functional theory calculation results prove the synergistic effect of the concentrated heat produced by interfacial solar steam generation and catalytic active sites of Fe‐BTEC on promoting H2O2 activation to form reactive oxidation radicals. This work not only provides a green strategy for upcycling waste polyimide, but also proposes a new approach to fabricate multi‐functional evaporators.

A 3D self-floating solar vapor generator based on a novel self-healing aero-hydrogel containing peach gum polysaccharide with durability and continuous operation

Solar energy interfacial evaporation represents a promising and sustainable approach with considerable potential for seawater desalination and wastewater treatment. Nonetheless, creating durable evaporators for continuous operation presents a challenge. Motivated by natural self-healing mechanisms, this study developed a novel 3D hybrid aero-hydrogel, which exhibited a self-healing efficiency of 89.4 % and an elongation at break post-healing of 637.7 %, featuring self-healing capabilities and continuous operation potential. Especially, the incorporation of hyperbranched water-soluble polymers (peach gum polysaccharide) endow the final solar water evaporators with a lower evaporation enthalpy of water, resulting in that the refined SVG3, with a notable water surface architecture and an expanded evaporation area, achieved a steam generation rate of 2.13 kg m−2 h−1 under 1 Sun. Notably, SVG2 achieved a high evaporation rate of 2.43 kg m−2 h−1 with the combined energy input of 1 Sun and 6 V, significantly surpassing the rate of 1.96 kg m−2 h−1 without voltage input. The results indicate that electrical energy significantly enhances and synergizes with SVG, facilitating continuous operation both day and night through the combined use of solar energy and electrical input. This study offers insightful perspectives for the strategic design of multifunctional hydrogels for solar water evaporation.

Impact of hydroxypropylation coupled with extrusion treatment on the morphological, structural, and rheological properties of sorghum and corn starch

The purpose of the present study to prepare hydroxypropyl derivatives (HP) instant (partially cold-water swell-able) starches via extrusion technique (Ex) from sorghum and corn. The native and hydroxypropylated (at propylene level 5 % and 12 %) starch extrudates were evaluated for functional, structural, thermal and rheological properties. The development of extrudates provides ease to industries as they are easily soluble in aqueous mediums and does not require any prior heating. The degree of substitution (DS) for all extrudates varied between 0.0083 and 0.1530 which is under limit and save to consume. The X-ray diffraction (XRD) analysis revealed that all extrudates exhibited V-type pattern while the intensity of peaks increased due to hydroxypropylation. The starch extrudates showed gel-like behavior since storage modulus (G′) was greater than loss modulus (G″). Non-Newtonian shear thinning behavior was observed for all extrudates. At lower temperature, HP-Ex at higher substitution level (12 %) demonstrated higher complex viscosity than native and low-substituted extrudates. Creep recovery of HP-Ex dispersion was more pronounced than native extrudates suggesting elastic nature of sorghum and corn starch extrudates. The differential scanning calorimetry (DSC) results revealed that HP-Ex were observed to gelatinize at lower temperatures and needed lower enthalpy of gelatinization (ΔHgel) because of their weakened structure after modification.

Investigation of nano-clusters evolved with Ti and Zr in ferritic ODS steel and their effect on microstructure and mechanical properties

In the present study, four nominal compositions Fe-15Cr-2W-0.3Y2O3-x (x = 0, 0.3Ti, 0.3Zr, 0.3Ti-0.3Zr) of ODS steel have been consolidated via spark-plasma-sintering of mechanically alloyed powders. All the samples were characterized via SEM, XRD, EBSD and TEM analysis and tested for hardness and compressive strength at room as well as elevated temperatures. Further, strength contributions of temperature dependent strengthening mechanisms were determined and correlated with the experimental values of compressive yield strength. Results suggest that contrary to Ti, addition of Zr was found with the precipitation of dense and much finer nano-clusters (∼3 nm) and observed to be more effective in enhancing the hardness and compressive strength at room as well as high temperatures. Composition containing both Ti and Zr solutes resulted in ultrafine grains of nearly uniform sizes and exhibited considerably enhanced hardness as well as compressive strength at all temperatures. However, it favoured the formation of Y-Zr-O nano-clusters instead of Y-Ti-O due to exhibiting lower formation enthalpy as determined from their reaction energies. As per the theoretically evaluated strength contributions, Orowan strengthening was found prevailed at high temperatures and it had a major contribution in compressive yield strength at room temperature as well. The study suggests the prevailing effect of formation of Y-Zr-O nano-clusters over Y-Ti-O nano-clusters in terms of obstacles to grain boundaries and mechanical properties which may provide an insight for the development of advanced nuclear materials.

Analysis of Renewable Source Self-Consumption Systems: Energy, Economic and Social Impact

This work analyzes renewable source self-consumption systems as an alternative to conventional fossil fuel sources for the residential, commercial, and industrial sectors. The proposed configuration is a hybrid array of individual or combined renewable energy sources like photovoltaic panels, wind turbines, hydroelectric micro-turbines, low enthalpy geothermal or biomass units, etc. The paper studies the energy balance for a prototype installation based on standard energy consumption and power supply from renewable sources, aiming to optimize the system performance by saving energy, increasing efficiency, and minimizing energy waste. The paper also analyzes the feasibility of the proposed configuration, its capacity for variable operating conditions adaptability, and the implementation factor in modern society. This work also evaluates the environmental impact of self-consumption systems powered by renewable sources in urban areas, which are deeply sensible to pollutant gasses emissions. The simulation analysis shows that this solution reduces greenhouse gas emissions and helps mitigate climate change by reverting the carbon dioxide balance in the atmosphere.

Pressure-Induced Irreversible Metallization Accompanying Phase Transition of Chalcopyrite Cu(In0.7Ga0.3)Se2.

Chalcopyrite copper-indium-gallium diselenides (CIGS) have emerged as promising materials with remarkable electronic properties and potential applicability to high-efficiency solar cells. The crystal and electronic structures of CIGS can be continuously tuned from their initial states under pressure. Although pressure-induced band gap closure in CIGS has been predicted in extensive theoretical studies, it has not been supported by experimental evidence. Here, we comprehensively investigate the pressure-dependent optical, electronic, and structural properties of Cu(In0.7Ga0.3)Se2 up to 42.6 GPa. Our experimental results reveal an irreversible electronic transition from the semiconducting to the metallic state at 14.3 GPa. Under compression, the Cu(In0.7Ga0.3)Se2 structure evolves from a tetragonal I4̅2d phase to an orthorhombic Pna21 phase, which has not been previously reported in chalcopyrite. More intriguingly, the Pna21 phase is irreversible and possesses smaller Cu-Se and In/Ga-Se bond lengths and a smaller Cu-Se-Cu bond angle than the I4̅2d phase. Density functional theory calculations indicate a lower enthalpy of the Pna21 phase than that of the I4̅2d phase at pressures above 10.6 GPa. Meanwhile, density of states calculations illustrate that metallization arises from the overlap of the Se p and Cu d orbitals as the bond length reduces. This pressure-induced behavior could facilitate the development of novel devices with various phenomena involving strong coupling of the mechanical, electrical, and optical properties of chalcopyrite.

Effect of ultrasound/CaCl2 co-treatment on the microstructure, gelatinization, and film-forming properties of high amylose corn starch

The effect of ultrasound/CaCl2 co-treatment on aggregation structure, thermal stability, rheological, and film properties of high amylose corn starch (HACS) was investigated. The scanning electron microscopy (SEM) images revealed the number of starch fragments and malformed starch granules increased after co-treatment. The differential scanning calorimetry (DSC) results showed the co-treated HACS got a lower gelatinization temperature (92.65 ± 0.495 °C) and enthalpy values (ΔH, 4.14 ± 0.192 J/g). The optical microscope images indicated that lesser Maltase crosses were observed in co-treated HACS. The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated ultrasound influenced the compactness of amorphous zone and CaCl2 damaged the crystalline region of HACS granules. Additionally, the rheology properties of HACS dispersion demonstrated the apparent viscosity of co-treated dispersion increased as the ultrasound time prolonged. The mechanical strength and structural compactness of HACS films were improved after ultrasound treatment. The mechanism of ultrasound/CaCl2 co-treatment improved the gelatinization and film-forming ability of HACS was that (i) ultrasound wave loosened the HACS granules shell, promoted the treatment of CaCl2 on HACS granules, and (ii) ultrasound wave improved the uniform distribution of HACS dispersion, increased the interaction between CaCl2 and starch chains during the process of film-forming.