Crystal Faces Research Articles

Theoretical study of potential energetic material CL-20/DNAN eutectic explosive based on molecular dynamics method.

The exploration of CL-20 eutectic has been a subject of fervent interest within the realm of high-energy material modification. Through the utilization of density functional and molecular dynamics methods, an investigation into the characteristics of hexanitrohexaazaisowurtzitane (CL-20)/2,4-dinitroanisole (DNAN) within the molar ratio range of 9:1-1:9 was conducted. This inquiry encompassed the scrutiny of molecular interaction pathway, attachment force, initiating molecular distance, unified energy concentration, and physical characteristics. Furthermore, EXPLO-5 was harnessed to prognosticate the explosion features and byproducts of unadulterated CL-20, DNAN, and CL-20/DNAN frameworks. The findings delineate a substantial differentiation in the electrostatic charge distribution on the surface between CL-20 and DNAN particles, signifying the preeminence of intermolecular interactions between disparate entities over those within similar entities, thus intimating the plausibility of eutectic constitution. Remarkably, the identification of maximal attachment force at a molar ratio of 4:6 suggests the heightened likelihood of eutectic formation, propelled primarily by electrostatic and van der Waals forces. The resultant eutectic explosive evinces intermediate reactivity and exemplary mechanical attributes. Moreover, the detonation achievement of the eutectic with a molar proportion of 4:6 straddles that of CL-20 and DNAN, representing a new type of insensitive high-energy material. The testing method employs the Materials Studio software and utilizes the molecular dynamics (MD) method to predict the properties of CL-20/DNAN co-crystals with different ratios and crystal faces. The MD simulation time step is set to 1 fs, and the total MD simulation time is 2 ns. An isothermal-isobaric (NPT) ensemble is used for the 2-ns MD simulation. The COMPASS force field is employed, with the temperature set to 295 K. The prediction of detonation characteristics and products is conducted using the EXPLO-5 software.

Morphological regulation of Pt/CeO2 and its catalytic dehydrogenation of methylcyclohexane in fixed bed reactor

A series of Pt/CeO2 compounds with hollow spheres (Pt/CeO2–S), wires (Pt/CeO2–W), and particle (Pt/CeO2–P) morphologies were prepared and further used for catalytic liquid organic hydrogen carrier (LOHC) dehydrogenation. The exposure and distribution of different crystal faces affected the nucleation process of crystals and then formed different microscopic morphologies. Compared with Pt/CeO2–W and Pt/CeO2–P, Pt/CeO2–S showed hollow spherical structures with significantly higher oxygen vacancy concentrations and specific surface areas. These structural differences not only affected platinum (Pt) dispersion, but also affected the activity and stability of the catalyst, thus promoting methylcyclohexane (MCH) conversion. The fixed bed reaction showed that Pt/CeO2–S had excellent catalytic activity, with the MCH conversion rate at 97.7 % and hydrogen release rate of 350.50 mmol/g(Pt)/min, and it still maintained stable activity after 72 h. Under the same conditions, the MCH conversion rates for Pt/CeO2–W and Pt/CeO2–P were only 77.23 % and 32.02 %, respectively. Therefore, through the growth pattern and morphology controls of catalyst supports, this was an effective means for improving the dehydrogenation performance of LOHC.

Preparation of compact spherulite of 2,2′,4,4′,6,6′-hexanitrostilbene (HNS) via specific adsorption of antisolvent combined with polymer

The application value of micro-nano hierarchical structure has been widely recognized in many fields, as it can greatly improve the surface performance of particles. Furthermore, the advantages of micro-nano hierarchical structure also bring new opportunities for the performance regulation of energetic materials, as an important material for both civilian and military applications, whose performance directly affects the application areas. This work developed a novel strategy for controlling the construction of compact spherulite of 2,2′,4,4′,6,6′-hexanitrostilbene(HNS) by utilizing antisolvent specific adsorption to generate noncrystallographic branching combined with the polymer additive to inhibit diffusion. Computational simulations revealed that toluene (TOL) exhibits specific adsorption on the (100) face of HNS through π-π interactions, while the polymer additive (Poly(acrylic acid), PAA) strongly interacts with each crystal face of HNS through hydrogen bonding, effectively inhibiting diffusion. Based on these findings, compact spherulites of HNS were successfully prepared by controlling supersaturation. The HNS spherulites exhibited superior flowability, specific surface area (11.84 m2/g for SP-I, 6.43 m2/g for SP-II), porosity (1.94 % for SP-I and 2.14 % for SP-II), and impact sensitivity (impact energy that can withstand increased from 4 J to 32.5 J for SP-I and to 11 J for SP-II). This work not only validates the effectiveness of antisolvent-induced branching in constructing compact spherulite structures, but also provides valuable insights into controlling crystal morphology. Furthermore, this research offers a promising approach to enhancing the safety and performance of energetic materials.

Facilistic preparation of zinc oxide nanoarrays on nickel foam via a one-step chemical bath method for photocatalysis

One-dimensional ZnO nanoarrays (ZnO NAs) were prepared on nickel foam using a one-step chemical bath deposition method. SEM and XRD confirmed the successful preparation of ZnO nanoarrays. TEM and Raman spectroscopy confirmed the preferential orientation of the ZnO nanorods along the (002) crystal plane. The Ni/ZnO NAs composites exhibited excellent photocatalytic degradation activity for ciprofloxacin (CIP) under UV light. UV–visible diffuse reflectance and transient photocurrent response characterization revealed that compared with ZnO nanorod powder, the Ni/ZnO NA composites increased the light absorption and reduced the complexation rate of photogenerated electron-hole pairs, thus improving the photocatalytic efficiency. In addition, the electron work functions of the two substances were calculated by using the crystal faces of Ni (111) and ZnO (002), and the calculation results confirmed the electron transfer paths. Electron transfer pathways further confirmed the possible reaction mechanism of Ni/ZnO NA degradation of CIP. Finally, Mott–Schottky tests were used to investigate the structure of the energy bands of the material and reveal its photocatalytic mechanism.

Stereoselective Crystallization of Chiral Pharmaceuticals Aided by Cellulose Derivatives through Helical Pattern Matching.

Stereoselective inhibition aided by "tailor-made" polymeric additives is an efficient approach to obtain enantiopure compounds through conglomerate crystallization. The chemical and configurational match between the side groups of polymers and the molecules of undesired enantiomer is considered to be a necessary condition for successful stereoseparation. Whereas in this contribution, we present an effective resolution of chiral pharmaceuticals by using cellulose acetates as the additives, which stereoselectively reside on the specific crystal faces of one enantiomer and inhibit its crystal nucleation and growth through helical pattern and supramolecular interaction complementarity. An investigation of nimodipine serves as a case study to highlight the novelty of this strategy wherein R-crystals exhibiting an impressive enantiomeric excess value of 97 % can be attained by employing a mere 0.01 wt % cellulose acetate. Guaifenesin and phenyl lactic acid are also well-resolved by utilizing this methodology. Our work not only brings about a brand-new design strategy for "tailor-made" additives, but will also promote the further exploration of the endless potential for utilizing natural biomolecules in chiral recognition and resolution.

Genesis and reservoir preservation mechanism of 10 000‐m ultradeep dolomite in Chinese craton basin

AbstractThe 10 000‐m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin. However, major challenges such as the genesis of dolomite, the formation time of high‐quality reservoirs, and the preservation mechanism of reservoirs have always limited exploration decision‐making. This research systematically elaborates on the genesis and reservoir‐forming mechanisms of Sinian–Cambrian dolomite, discussing the ancient marine environment where microorganisms and dolomite develop, which controls the formation of large‐scale Precambrian–Cambrian dolomite. The periodic changes in Mg isotopes and sedimentary cycles show that the thick‐layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale. Lattice defects and dolomite embryos can promote dolomitization. By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights, the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed, and the mechanism of dolomitization was also demonstrated. The properties of calcite and dolomite (104)/(110) grain boundaries and their dissolution mechanism in carbonate solution were revealed, showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs. The in situ laser U‐Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks. This research also proposed that dolomitization occurred during the quasi‐contemporaneous or shallow‐burial periods within 50 Ma after deposition and pores formed during the quasi‐contemporaneous to the early diagenetic periods. And it was clear that the quasi‐contemporaneous dolomitization was the key period for reservoir formation. The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large‐scale dolomite reservoirs. It clarifies the targets for oil and gas exploration at depths over 10 000 m. The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10 000‐m deep oil exploration.

Human collagen sequence polypeptides mediated biomineralization and its molecular mechanism

Biotechnology provides alternatives for regenerative medicine with more controllable functions. Herein, the polypeptides encoded with human collagen I amino-acid sequences were studied for the first time to modulate biomimetic hydroxyapatite (HAP). With a length of 50–100 nm and a width of 20–30 nm, the HAP crystal formed was plate-like. The interaction of the human collagen sequence polypeptide on the (001), (100), and (211) crystal faces of HAP crystal had been studied using Molecular Dynamics (MD) simulations, respectively. Based on MD simulations, van der Waals forces and hydrogen bonds are the main interactions between polypeptides and HAP through the –NH2, –CH2–, –OH, and –COOH, respectively. According to the calculated results, der Waals forces might be the main interaction. The human collagen sequence polypeptides exhibited the highest adsorption energy on the (001) plane of HAP, significantly higher than any of the adsorption energy on the (100) and (211) planes. Therefore, the growth of the (001) would be inhibited, which kept accurate with the result of images from the Transmission Electron Microscope (TEM). Study results provide a basis for rational designing of peptides with human collagen sequences to regenerate hard tissues.

Ionic Liquids Functionalized Copper Catalytic Systems for Electrocatalytic Carbon Dioxide Reduction

The extensive combustion of fossil fuels results in excessive release of carbon dioxide (CO2), causing a global environmental crisis. It is imperative to develop sustainable methods for converting CO2 into renewable energy sources. Electrochemical reduction of CO2 (CO2RR) offers the potential to generate valuable chemicals, including C1 products (e.g., carbon monoxide, methane, etc.) and C2+ products (e.g., ethene, ethanol, acetic acid, propyl alcohol, etc.). Copper‐based (Cu‐based) catalysts show promise for producing value‐added C2+ products, but they face challenges like low selectivity and stability. The catalytic performances of Cu‐based catalysts can be promoted through electronic structure adjustment, selective crystal face exposure, as well as molecular additive approaches. Ionic liquids (ILs), known for their strong CO2 adsorption capacity, adjustable hydrophobicity, and wide chemical window, hold significant promise for addressing the current challenges associated with Cu‐based catalysts. This review provides a comprehensive overview of the structural characterization and catalytic mechanisms of ILs used in Cu‐based CO2RR catalytic systems. Additionally, it offers suggestions for future research avenues regarding IL‐functionalized Cu catalysts.

Stress relief and crystal face transition process contribute to the stability of zinc anodes

Zn electrodes are suffering the dendrite growth owing to the enrichment of local space charge, distinct exposed face and residual stress. In this work, we investigated the crystal face properties and stress state of Zn foil through static energy calculations, dynamic crystal growth analysis and finite element simulation of stress states. Then thermal driven is deployed to modify the exposure face and residual stress of Zn foil, aiming for a dendrite-free electrode. The calculation of surface energies and simulation of crystal growth models for different crystal faces indicate that the (001) face can maintain stability during deposition. Inspired by this mechanism, the (101) exposed commercial Zn foil is modified by thermal processing. Firstly, the exposure level of the (001) face increases, though only the peak corresponding to the (002) crystal face is observed, due to the extinction effect of the densely packed plane (001) face. Further, the surface morphology becomes smooth and the stress is released with the progresses time. These stress relief and crystal face transition process strengthen the uniformity of ion distribution, and increase the interface stability during the crystal growth, which reduce the defect sites in the deposition. As a result, the Zn electrode exhibits tiny voltage hysteresis and outstanding cycle stability, which reveals improved electrochemical performance. Additionally, Li and Na can also be improved in exposed crystal faces and release strain energy through similar methods to enhance cycling stability.

Theoretical investigation of the sm-BiVO4 of different surfaces for photocatalytic properties

The photocatalytic performance of a semiconductor photocatalyst mainly depends on the exposure degree of the crystal surface with high catalytic performance. The research focused on sm-BiVO4, which exhibits superior photocatalytic performance, as the subject of the study. Based on Density Functional Theory (DFT), the stability, electrical properties, optical properties, adsorption properties and surface activity of 7 low-index faces and one easily formed (112) crystal face of monoclinic clinobisvanite bismuth scheelite (sm-BiVO4) were investigated. The results show that the (001) crystal faces of sm-BiVO4 have the highest stability compared to other crystal faces. Bi atoms have the highest number of electrons from VO43−, the highest light absorption efficiency and the highest surface activity. This work not only contributes to the understanding of sm-BiVO4 but also demonstrates that the (001) crystal faces of sm-BiVO4 has great potential for photocatalytic applications.

Hydrogen permselective membrane prepared by plasma treatment of porous ceramic substrates

Abstract Demand for hydrogen is increasing as we move toward a decarbonized society. Membrane separation methods have attracted attention as a way to reduce the cost of hydrogen production. In this study, we focused on boron nitride (BN) as a chemically stable porous substrate material. CVD treatment at 250°C has been investigated for porous BN, but selectivity did not develop. Therefore, we focused on atmospheric pressure plasma as a treatment method. The objective of this study is to develop a membrane with high hydrogen selective permeance by immersion in silicon alkoxide after plasma treatment. After plasma treatment for 100 s, the H2 permeance was 3.52×10−6 [mol m−2 s−1 Pa−1] and the H2/N2 permeance ratio was 18.25. Since molecular hydrogen can pass between the BN crystal faces, it is considered that silica reacted with the hydroxy groups formed on BN by plasma treatment and blocked the space between crystals. Therefore, it is suggested that the performance of the separation membrane changes depending on the number and distribution of hydroxyl groups by plasma treatment, and further stabilization is needed.

Adjusting Interface Dynamics: A New Insight into the Role of Electrolyte Additive in Facilitating Highly Reversible (002)‐Textured Zinc Anode at High Current and Areal Densities

AbstractFacilitating (002)‐textured zinc growth is crucial for achieving dendrite‐free zinc deposition in zinc‐ion batteries. Electrolyte engineering holds promise in directing zinc electrodeposition toward this desired orientation. However, despite the (002) plane's lower surface energy compared to other facets, it remains unclear why this plane does not dominate zinc crystal faces during electrodeposition under normal conditions. This knowledge gap underscores the need to better understand zinc electrodeposition behaviors and the influence of electrolyte compositions on its crystallographic texture. This study explores different tetraazamacrocycle derivatives as electrolyte additives. It reveals that achieving (002)‐textured zinc deposition is not solely dictated by thermodynamic equilibrium but also significantly influenced by interface dynamics. In typical ZnSO4 electrolytes, imbalanced kinetics among reduction, ion diffusion, and adatom diffusion processes lead to electroconvection and disorderly zinc accumulation, hindering proper zinc growth. In contrast, introducing specific tetraazamacrocycle derivative in the electrolyte regulates reduction rate, enhances limiting current density, and expedites adatom diffusion, mitigating hydrodynamic instability and dendrite growth. This regulation restores the thermodynamically favorable flat (002)‐textured zinc deposition, extending the zinc anode's lifespan to 1800 h at 5 mA cm−2 and 5 mAh cm−2, enabling the fabrication of a high‐performance zinc ion hybrid capacitor prototype capable of stable operation for 40 000 cycles.

Exposure to hypoxic Bi2MoO6 nanobelts with {001} crystal faces and face-dependent visible light driven photocatalytic activity

This study explores the photocatalytic activity of oxygen-deficient Bi2MoO6 photocatalysts with exposed {001} crystal planes, utilizing a combined approach of experiments and Density Functional Theory (DFT) to investigate enhanced catalytic performance to unravel the underlying mechanisms. The unique interlayer structure of Bi2MoO6 semiconductor facilitates the construction of surface oxygen vacancies (SOVs) on the {001} crystal plane. However, its further photocatalytic applications are limited by the inherent photogenerated electron recombination and lack of active sites. In order to improve the performance of photocatalytic reactions, a systematic study was conducted on the exposure of {001} crystal faces in Bi2MoO6 crystals under hypoxia induced by chloride ions (Cl-). After 30 min of visible light irradiation, Bi2MoO6-4 (with the addition of 1 mmol sodium chloride in Bi2MoO6) sample showed good photocatalytic degradation activity towards Rhodamine B (RhB), reaching 99.24 %, which is 1.67 times higher than pure Bi2MoO6. Furthermore, the transient photocurrent value of Bi2MoO6-4 is about 1.32×10−7A, which is about twice that of Bi2MoO6-1. The above results can be attributed to the synergistic effect of SOVs induced by Cl- and {001} crystal planes in Bi2MoO6, while the {001} crystal surface has been proven by DFT to accelerate surface charge transfer and enhance molecular oxygen activation. This study highlights the advantages of regulating crystal faces exposure in improving photocatalytic activity and provides a promising strategy for designing other Bi based photocatalysts for environmental remediation.

Lead-Free Bismuth-Based Perovskite X-ray Detector with High Sensitivity and Low Detection Limit.

Bismuth-based halide perovskites have shown great potential for direct X-ray detection, attributable to their nontoxicity and advantages in detection sensitivity and spatial resolution. However, the practical application of such materials still faces the critical challenge of combining both high sensitivity and low detection limits. Here, we report a new type of zero-dimensional (0D) perovskite (HIS)BiI5 (1, where HIS2+ = histamine) with high sensitivity and a low detection limit. Structurally, the strong N-H···I hydrogen bonds between HIS2+ cations and inorganic frameworks enhance the rigidity of the structure and diminish the intermolecular distance between adjacent inorganic [Bi2I10]4- dimers. By virtue of such structural merits, single crystal 1 exhibits excellent physical properties perpendicular to both the (001) and (010) faces. Perpendicular to the (010) face, 1 exhibited a high electrical resistivity (2.31 × 1011 Ω cm) and a large carrier mobility-lifetime product (μτ) (2.81 × 10-4 cm2 V-1) under X-ray illumination. Benefiting from these superior physical properties, it demonstrates an excellent X-ray detection capability with a sensitivity of approximately 103 μC Gyair-1 cm-2 and a detection limit of 36 nGyair s-1 in both directions perpendicular to the (001) and (010) crystal faces. These results provide a promising candidate material for the development of new, lead-free, high-performance X-ray detectors.

Effect of Additives on the Morphology of γ-Aminobutyric Acid Crystals.

The effect of surfactant, polymer, and tailor-made additives on the crystallization of γ-aminobutyric acid (GABA) was studied in this work. Cooling crystallization of GABA in water yielded plate-like crystals. In the presence of sodium stearate, polyhedral block-like crystals of GABA were obtained. Hydroxyethyl cellulose (HEC) led to rod-like crystals, in which the morphology was associated with additive concentrations. Six kinds of amino acids were used as tailor-made additives, and they exhibit different influences on crystal shape and size. The induction time of GABA was determined in the absence and presence of additives. The results showed that sodium stearate promoted nucleation, while HEC, l-Lysine, l-histidine, and l-tyrosine inhibited nucleation. Crystal face indexing, Hirshfeld surface analysis, and molecular dynamics (MD) simulation in aqueous solution-crystal systems were carried out to investigate the affecting factors of different crystal faces. The polymer additive was selected as an example during MD simulation to calculate intermolecular interactions between the crystal face and solvent or additive. The effect of the additive on the mobility of the solute in solution was also evaluated by mean-square displacement. The additive offers an effective approach for changing crystal morphology and particle size and adapting it to different production requirements.

Interplanar spacing and nanosheet thickness regulation of carbon nitride and its “cold” catalytic hydrogen production performance under 10 W LED irradiation

Investigation of hydrogen production catalysis under low-temperature and low-power light irradiation, such as LEDs, is important for energy conservation in cold natural conditions. Interlayer charge transfer in g-C3N4 nanosheets is influenced by the crystal face spacing and nanosheet thickness, due to rapid photogenerated carrier recombination and slow charge transfer, thus enhancing hydrogen production capabilities. Few studies have controlled both crystal face spacing and nanosheet thickness simultaneously. In this research, copper-phosphorus co-doped g-C3N4 was synthesized through one-step thermal polymerization, achieving both control over nanosheet thickness and crystal surface spacing. The hydrogen production rate of 0.5 %Cu/1 %P doped g-C3N4 was increased by 5.25 times and reached 958.98 μmol/g/h under 10 °C and 10 W LED illumination. Copper and phosphorus doping that reduced (002) surface spacing of g-C3N4, resulting in thinner nanosheets. This structural modification facilitated interlayer charge transfer and suppressed photogenerated carrier recombination. This research provides a novel insight and strategy for designing hydrogen production photocatalyst at low temperatures and with low energy consumption.

Dynamic Growth Mechanism of Crystal Faces of Surface Martensite with Habit Planes in Proximity to {112}

Dynamic Growth Mechanism of Crystal Faces of Surface Martensite with Habit Planes in Proximity to {112}

Enhancing Performance and Stability of p-i-n Perovskite Solar Cells with Ag-Cu Codeposited Alloy Electrodes.

In the development of back electrodes for perovskite solar cells (PSCs), the major challenges are stability and cost. To address this, we present an innovative approach: Simultaneous evaporation of two independently controlled sources of metal materials was performed to achieve a uniform distribution of the alloy electrodes. In this study, Ag-Cu alloys (the molar ratio of Ag/Cu is 7/3) with a high-index crystal face (111) and a work function matching perovskite were prepared using a codeposition technique. These properties mitigate nonradiative carrier recombination at the interface and reduce the energy barrier for carrier migration. Consequently, compared to Ag based PSCs (22.77%), the implementation of Ag-Cu alloy (Ag/Cu is 7/3)-based PSCs resulted in a power conversion efficiency of 23.72%. In a 1500 h tracking test in ambient air, the Ag-Cu alloy (Ag/Cu is 7/3)-based PSCs maintained their initial efficiency of 86%. This can be attributed to almost no migration of elements from the Ag-Cu alloy electrode to the perovskite layer. Our work presents a vital strategy for improving the stability of PSCs and reducing the costs associated with the back electrode in PSCs.

Hf-Doped CoP Hollow Nanocubes as High-Performance Electrocatalyst for Oxygen Evolution Reaction.

Designing and synthesizing hollow frame structures with unique three-dimensional open structures in electrocatalysis remain a challenge. Etching is an effective method to synthesize metal-organic frameworks (MOFs) with a hollow structure and rich function. Herein, we report the design and synthesis of Hf-doped CoP hollow nanocubes by selective etching and ion exchange. Different from the traditional etching method, we used acid xylenol orange solution to etch typically the (211) crystal face of ZIF-67, obtaining the unique bell-like structure, named XO-ZIF-67. Subsequently, Hf-doped CoP hollow nanocubes were formed by Hf4+ doping and simple phosphating treatment. Electrochemical tests showed that the overpotential of the obtained catalyst is only 291 mV at the current density of 10 mA cm-2 when applied in catalyzing the oxygen evolution reaction (OER). Furthermore, the catalyst shows excellent stability when running in 1 M KOH solution for 25 h.

Insight into the Manipulation Mechanism of Polymorphic Transformation by Polymers: A Case of Cimetidine.

Employing polymer additives is an effective strategy to realize the manipulation of polymorphic transformation. However, the manipulation mechanism is still not clear, which limit the precise selection of polymeric excipients and the development of pharmaceutical formulations. The solubility of cimetidine (CIM) in acetonitrile/water mixtures were measured. And the polymorphic transformation from CIM form A to form B with the addition of different polymers was monitored by Raman spectroscopy. Furthermore, the manipulation effect of polymers was determined based on the results of experiments and molecular simulations. The solubility of form A is consistently higher than that of form B, which indicate that form B is the thermodynamically stable form within the examined temperature range. The presence of polyvinylpyrrolidone (PVP) of a shorter chain length could have a stronger inhibitory effect on the phase transformation process of metastable form, whereas polyethylene glycol (PEG) had almost no impact. The nucleation kinetics experiments and molecular dynamic simulation results showed that only PVP molecules could significantly decrease the nucleation rate of CIM, due to the ability of reducing solute molecular diffusion and solute-solute molecular interaction. A combination of crystal growth rate measurements and calculations of the interaction energies between PVP and the crystal faces of CIM indicate that smaller molecular weight PVP can suppress crystal growth more effectively. PVP K16-18 has more impact on the stabilization of CIM form A and inhibition of the phase transformation process. The manipulation mechanism of polymer additives in the polymorphic transformation of CIM was proposed.