Search

In this paper, the N,N′-dicyclohexylterephthalamide (DCHT) with various morphologies and sizes was prepared by antisolvent precipitation at room temperature, and DCHT single crystals were also grown. Among them, DCHT crystals precipitated from deionized water (H2O), alcohol (C2H5OH) and N′N-dimethylformamide (DMF) are particle-like crystallites (DCHT-H2O), cuboid (DCHT-C2H5OH) and large rectangular crystals (DCHT-DMF), respectively. The powder XRD results show that the (002) plane is the dominant growth plane of the DCHT crystals, and the diffraction peak intensity of (100) plane is negatively correlated with the size of the DCHT crystals. The single-crystal XRD results show that the minimum distance between the two nearest DCHT molecules is the hydrogen bond distance (2.21 Å), and the (100) crystal plane is the plane of hydrogen bonding between DCHT molecules. Thus, it is speculated that the hydrogen bonding interaction is the main driving force for the growth of DCHT crystals. Further, the effect of different morphologies and sizes of DCHT on isotactic polypropylene (iPP) crystallization was investigated. Non-isothermal crystallization studies revealed that the DCHT size plays a decisive role in increasing the crystallization temperature of iPP. Through isothermal crystallization, it was found that the upper critical temperature of β-α growth "transition" of iPP could be related to the morphology of DCHT. Finally, the iPP film was attached to the surface of DCHT single crystal, and its crystallization behavior was studied. It is confirmed that the (001) plane is the epitaxial plane of DCHT to the β-iPP molecular chain, while the epitaxial plane of β-iPP is the (110) plane. [ABSTRACT FROM AUTHOR]

In the synthesis of metal–organic frameworks (MOFs), the choice of the metal precursor plays a key role because of the influence that it can exert on the crystallization kinetics. The present work explores the use of metal-carbamato complexes for the synthesis of benchmark MOFs, namely HKUST-1 and UiO-66. Cu2(O2CNEt2)4·2NHEt2 and Zr(O2CNEt2)4, prepared using straightforward CO2 fixation reactions starting from the corresponding metal chlorides and diethylamine, were employed as metal precursors for MOF formation. The synthesis conditions, including the solvent, temperature, and ligand protonation degree, were systematically investigated, revealing metal carbamates as highly reactive precursors due to their prompt release of CO2 and amine upon reaction with protic species, i.e., the polycarboxylic linkers. This property of metal carbamates allowed us to identify room temperature protocols to achieve MOFs with comparable properties to those obtained using traditional metal precursors. Subsequent optimization of the reaction conditions led to the design of a one-pot synthetic strategy for HKUST-1, starting directly from copper(II) chloride and diethylamine under a CO2 atmosphere. The MOFs were characterized using various techniques, including powder X-ray diffraction, N2 sorption analysis, 1H nuclear magnetic resonance spectroscopy, and CHN elemental analysis, and compared to reference samples prepared according to literature procedures. [ABSTRACT FROM AUTHOR]

Scaling up perovskite solar cells stands as one of the frontiers in advancing this rapidly growing technology. Yet, controlling perovskite thin‐film crystallization during and post‐printing differs significantly from lab‐scale processes that have yielded record device efficiencies. This study investigates antisolvent treatment for slot‐die‐coated perovskite solar cells using in situ optical spectroscopy and comparing among multiple antisolvents. The antisolvent bath used in slot‐die coating affects the perovskite crystallization and film quality differently when comparing to the established spin‐coating antisolvent treatment process. A novel dynamic antisolvent method, employing either vortex or laminar flow, is developed. It outperforms steady‐bath techniques in generating high‐quality, haze‐free films. Optimization studies identify critical treatment times. Implementing this novel antisolvent treatment leads to a peak average power conversion efficiency of 15.62% and the highest device efficiency of 18.57%, an excellent performance for slot‐die‐coated MAPbI3 devices printed and tested under ambient conditions. The method is validated for an alternative perovskite composition, FA0.9Cs0.1PbI3, and printing technique, blade coating. This research highlights the importance of in situ analysis for enhancing perovskite film quality and introduces scalable approaches for controlling large‐area film crystallization kinetics, driven by the demand for efficient and scalable manufacturing processes in the field of perovskite solar cells. [ABSTRACT FROM AUTHOR]

The impact of adding ethylene vinyl acetate copolymer (EVA 80) and 1 wt% TiO2 nanoparticles on the morphology and crystallization behavior of poly(lactic acid) blends was investigated using DSC, SEM, and POM. Thermal analysis revealed the enhancement of crystallinity of PLA in the presence of TiO2 and higher EVA 80 content in the blend. The PLA and EVA 80 components showed compatibility, as evidenced by the shift of the glass transition temperatures of the PLA phase in the blend to lower values compared to neat PLA. The lower temperature shift of the cold crystallization of the PLA and the formation of the small spherulites of the PLA in the blends indicated that the EVA 80 and TiO2 act as a nucleating agent for crystallization. The non-isothermal crystallization parameters of the composites were evaluated using Avrami's modified model, the MO approach, and Friedman's isoconversional method. The Avrami's modified rate constant (K) and the effective activation energy values significantly increased with the incorporation of EVA 80 and TiO2 nanoparticles. Furthermore, the thermogravimetric analysis (TGA) showed improved thermal stability of PLA by adding EVA 80 and TiO2. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites are highly regarded materials for improving the stability of perovskite solar cells (PSCs). Wherein, self‐additive 2D perovskites have recently been proposed to provide substantial strategies for managing the crystallization kinetics and bulk defects. For a profound understanding of the formation mechanisms, herein, with selecting three self‐additive 2D perovskites as demonstrations, a comprehensive analysis of the self‐additive behavior combing experimental and theoretical calculations is conducted. Self‐additive 2D perovskites exhibit more suitable formation energies and strong interaction, which is conducive to realize the self‐additive effect to form more stable structure. As demonstrated, glycine (Gly)‐based spacer cations played a pivotal role in the nucleation and growth of 2D perovskites by adjusting the aggregation state of colloids precursor, resulting in excellent‐quality films with large average grain size (≈3 µm). Meanwhile, theoretical analysis of electronic distribution and binding energies (Eb) revealed that glycine ethyl ester (Gly‐E) perovskite possesses highly robust internal interactions, which will effectively mitigate defect formation and enhance device stability. Endowing with the above outstanding feature, Gly‐E devices exhibited an optimized PCE of 21.60%, one of the highest PCEs among all 2D RP PSCs (n ≤ 6). The findings provide a basis for the rational design of self‐additive 2D perovskites and achieving highly‐performance 2D RP PSCs. [ABSTRACT FROM AUTHOR]

p-type semiconductors are significant for integrated nanoelectronics. Tellurium (Te), a mono-elemental material, is a p-type semiconductor with high mobility. Its outstanding performance renders it widely applicable in the fields of electronics and optoelectronics. However, the wafer-scale fabrication of Te thin films is challenging. In this study, we reported an ion-bean sputtered Te thin film and investigated the effects of annealing temperatures. Annealing-induced crystallization kinetics were assessed through Raman spectroscopy, x-ray diffraction, and atomic force microscopy. After annealing, the film's conductivity increased from 10−5 to 10−4 S and mobility from 18 to 53 cm2 V−1 s−1. Dual AC resonance tracking switching spectroscopy piezoelectric force microscopy is used to investigate piezo/ferroelectric properties. The coercive voltages are −2 and 4 V respectively, and the effective piezoelectric coefficient (d33) is 40 pm/V. Butterfly and phase-switching loops demonstrate its possible ferroelectricity. The Te thin film has potential applications in optoelectronics, nonvolatile memory devices, and neuromorphic computation. [ABSTRACT FROM AUTHOR]

The crystallization process of low melting point CaO–SiO2–Al2O3–MgO system inclusions during the continuous casting and hot rolling process greatly affects the deformability of inclusions. The effect of Al2O3 and MgO contents on the crystallization characteristics of CaO–SiO2–Al2O3–MgO system melts representing the typical oxide inclusions in Si–Mn deoxidized steels is systematically investigated. The continuous cooling transformation and time–temperature transformation experiments are carried out. The results reveal that the increase of Al2O3 contents restrains the crystallization process of the melt, whereas the crystallization tendency of the melt is promoted with the increase of MgO contents. The precipitated phases are predominately 2CaO·MgO·2SiO2 and 3CaO·MgO·2SiO2, and the primary crystalline phase is unaffected by the changes of Al2O3 and MgO contents. To obtain low melting point plasticized inclusions with limited crystallization ability, it is recommended to control the Al2O3 and MgO contents greater than 15 wt% and below 5 wt%, respectively. The isothermal treatment is suggested to be controlled within a proper temperature range (1175–1250 °C) to decrease the crystallization kinetics. The oxide system's viscosity change is the limiting kinetic factor in the crystallization process, and it can be utilized to predict the system's crystallization tendency. [ABSTRACT FROM AUTHOR]

Describing the solidification process is very important in polymer processing. In polypropylene (PP), the increase of viscosity, named stiffening or hardening, is determined by a rise in crystallinity. When PP flows in a channel or is stretched on a chill roll, the stress induces an anticipated crystallization and thus can lead to an unexpected solidification. This study explores how flow fields influence the crystallization behavior of PP. A controlled-stress rheometer was used to investigate the effect of short shear stress steps on crystallization kinetics. The results revealed that applying a stress step significantly increased the rate of crystallization compared to a non-stressed sample. This acceleration is attributed to the stress-induced orientation of macromolecules, which promotes nucleation. Furthermore, longer durations of applied stress led to a faster increase in viscosity, indicating a higher nucleation density with increasing stress exposure. A mastercurve approach validated the consistency of the model describing the stress-crystallization relationship. The calculated parameter relating to nucleation density confirmed a linear increase with stress duration, allowing estimation of the nucleation rate during shear. [ABSTRACT FROM AUTHOR]

The formation of polylactide stereocomplex (sc-PLA), involving the blending of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA), enhances PLA materials by making them stronger and more heat-resistant. This study investigated the competitive crystallization behavior of homocrystals (HCs) and stereocomplex crystals (SCs) in a 50/50 PLLA/PDLA blend with added polyethylene glycol (PEG). PEG, with molecular weights of 400 g/mol and 35,000 g/mol, was incorporated at concentrations ranging from 5% to 20% by weight. Differential scanning calorimetry (DSC) analysis revealed that PEG increased the crystallization temperature, promoted SC formation, and inhibited HC formation. PEG also acted as a plasticizer, lowering both melting and crystallization temperatures. The second heating DSC curve showed that the pure PLLA/PDLA blend had a 57.1% fraction of SC while adding 5% PEG with a molecular weight of 400 g/mol resulted in complete SC formation. In contrast, PEG with a molecular weight of 35,000 g/mol was less effective, allowing some HC formation. Additionally, PEG consistently promoted SC formation across various cooling rates (2, 5, 10, or 20 °C/min), demonstrating a robust influence under different conditions. [ABSTRACT FROM AUTHOR]

Context: Although the crystallization of monosodium urate monohydrate (MSUM) has a crucial role in the occurrence of gout, which is an inflammatory arthritis disease, theoretical models have not been able to describe all features observed in its seeded growth kinetics. In contrast to previous modeling approaches, we show that our model can reproduce qualitative features typically observed in experiments. In particular, our results show that the higher the initial supersaturation and the lower the viscosity, the faster the crystallization kinetics, and they also indicate that there are distinct growth regimes for low and high concentrations of seeds. Methods: In this work, we introduce an alternative approach based on a master equation that allows us to incorporate hypotheses for the seeded growth crystallization of MSUM in a more transparent way. Such an approach includes not only effects that are related to the finite time-dependent supersaturation and concentration of seeds, but it can also be used to determine how the viscosity of the solution can affect the crystallization kinetics of MSUM molecules. [ABSTRACT FROM AUTHOR]

Seeding (SD) is a chocolate pre-crystallization technique (PT) that serves as a more efficient alternative to conventional tempering (CT), yielding equivalent characteristics within the category of well-tempered chocolate. However, variability in macroscopic quality attributes may persist. This study aims to discern variations among well-tempered chocolates obtained through various configurations of PTs: CT, SD, and a combination of both (CS), focusing on changes during pre-crystallization, solidification, and subsequent storage at 20 °C. The increased yield stress (> 1.2 Pa) of pre-crystallized chocolate in comparison to non-tempered chocolate, melting peak alignment with the β V cocoa butter (CB) polymorph (29–34 °C) after 6-h storage and fat-bloom resistance up to 9 months, affirm the successful integration of different PTs within the well-tempered chocolate category. However, distinct melt⟶2L⟶3L lamellar packing transition mechanisms for each PT were identified in the first hour of solidification through synchrotron-assisted time-resolved X-ray scattering. Varied polymorphic transition and microstructural growth kinetics were also observed over 28 days of storage, as indicated by melting profiles. CS chocolate exhibited limited transition, remaining stable as β V . In contrast, CT and SD underwent rapid microstructural growth with an indication of a small fraction of CB polymorph transitioning to the undesirable β VI CB polymorph (> 34 °C), linked to fat bloom development. Surface topography observation through accelerated shelf-life test at 26 °C over 9 months marked the link with CB crystal microstructural growth, with fat bloom occurring faster on SD chocolate, then CT chocolate, and finally the CS chocolate. These findings highlight the potential to tailor crystallization kinetics by adapting PT to achieve improved product qualities, such as extended fat-bloom resistance or accelerated solidification while remaining within the well-tempered category. [ABSTRACT FROM AUTHOR]

Polyaryletherketone (PAEK) thermoplastic composite materials have received increasing attention for the manufacturing of composite structures. One manufacturing process of great interest for PAEK composite structures is automated fiber placement, which can increase the throughput of complex part fabrication and reduce the use of autoclaves for assembly of composite parts. Understanding the thermal effects of the material allows the control and adjustment of manufacturing variables to assure the integrity of the composite structure. PAEK resins and carbon fiber reinforced composites have been analyzed using differential scanning calorimetry to study crystallization kinetics. Isothermal and non‐isothermal tests were conducted, and the time‐dependent crystallization kinetics were modeled using the Velisaris and Seferis model for isothermal processes and the Gaussian process regression method for non‐isothermal processes. The results show the influence of the thermal conditions and the chemical structures considering the ketone content, and the effects of the presence of the carbon fibers on crystallization kinetics. The models utilized describe with high accuracy the time‐dependent crystallization kinetics of PAEK composite materials. An artificial neural network application was also implemented using the non‐isothermal PAEK composite models for further prediction of relative volume crystallinity and crystallization rate. Highlights: Polyaryletherketone (PAEK) materials crystallize differently depending on the crystallization conditions.Carbon fibers influence the crystallization response in PAEK polymers.Machine learning was used to characterize crystallization kinetics.Activation energies were obtained for different thermal treatments.Artificial neural network tool was developed for PAEK composites in non‐isothermal regimes. [ABSTRACT FROM AUTHOR]

Poly (butylene terephthalate) (PBT)/poly (ethylene glycol‐co‐cyclohexane‐1, 4‐dimethanolterephthalate) (PETG) blends were prepared by melt blending using a twin screw extruder. The non‐isothermal crystallization behaviors of PBT/PETG blends were investigated using differential scanning calorimetry (DSC). The results showed that the crystallization peaks of the PBT/PETG blends moved gradually toward lower temperature and the crystallinity decreased with the increase of PETG content. The PBT/PETG blends all show double melting peaks, which the low‐melting peak temperature Tm1 becomes lower as the cooling rate increases, but the high‐melting peak temperature Tm2 is not related to the cooling rate. The Jeziorny's method showed that the faster the cooling rate is, the shorter the crystallization time is required for the PBT/PETG blends. The Mo's method showed that the crystallization rate of the blends initially decreased and then increased with the addition of more PETG. The activation energy of non‐isothermal crystallization calculated by the Kissinger method is similar to that of the Takhor method. Highlights: The efficient blending of PBT and PETG was realized by twin screw extruder, which opened up a new way for the preparation of polymer materials.The crystallization behavior of PBT/PETG blends was successfully regulated, and the effect of PETG content on the crystallization peak temperature and crystallinity was revealed.The crystallization characteristics and kinetic behavior of the blends were comprehensively evaluated by DSC, Jeziorny method, Mo Zhishen method, and Kissinger method. [ABSTRACT FROM AUTHOR]

This study investigates the effects of molecular weight and crystallinity of polylactic acid (PLA) on the morphology and crystallization behavior of polyhydroxybutyrate (PHB)/PLA blends. Utilizing a solution casting method, we discovered that the molecular characteristics of PLA significantly influence the thermal and structural properties of the blends. The lower molecular weight and amorphous PLA notably broadened the temperature range for PHB's banded spherulite formation, indicating enhanced miscibility. In contrast, semicrystalline PLA variants produced smaller spherulites within large PHB matrices. The high molecular weight PLA had an unusual, relatively low melting point which led to a competition between the molecular weight effect and the supercooling effect regarding the isothermal crystallization kinetics. The blend morphology was observed in thin films in which the usual crystal formation of PHB was severely hindered in the presence of crystalline PLA but could form thin lamellae when the PLA was amorphous. At ultra‐thin thickness, where crystallization is impossible, the amorphous co‐continuous structure of the blends was revealed by melting the film. Our research contributes to the development of advanced biodegradable materials for environmental sustainability, emphasizing the intricate interplay between polymer blend components that can be tuned for specific applications. Highlights: The study explores the blend morphology and crystallization of PLA/PHB.The temperature range for PHB's spherulite formation broadens with PLA.PLA's partial miscibility with PHB shifted Tg and caused delayed Tm of PHB.Usual PHB crystal formation is hindered with crystalline PLA.Thin PHB lamellae formed within amorphous PLA and observed via AFM. [ABSTRACT FROM AUTHOR]

The results of the stepwise-dilatometry study of the influence of the graphite content on the temperature dependence of the specific volume of nanocomposites based on high-density polyethylene and graphite are presented. It has been found that, for nanocomposites with the graphite content of 1.0–10 wt %, the first-order phase transition occurs at 115°C. For samples containing 15–20 wt % graphite, this transition occurs at 110°C. On the basis of the dilatometric curves, the glass transition temperatures of the nanocomposites have been determined. The kinetics and mechanism of crystallization of nanocomposites have been considered. [ABSTRACT FROM AUTHOR]

Poly(ethylene terephthalate) (PET) is a thermoplastic polyester with excellent thermal and mechanical properties, widely used in a variety of industrial fields. It is a semicrystalline polymer, and most of the industrial success of PET derives from its easily tunable crystallization kinetics, which allow users to produce the polymer with a high crystal fraction for applications that demand high thermomechanical resistance and barrier properties, or a fully amorphous polymer when high transparency of the product is needed. The main properties of the polymer are presented and discussed in this contribution, together with the literature data on the crystal structure and morphology of PET. This is followed by an in-depth analysis of its crystallization kinetics, including both primary crystal nucleation and crystal growth, as well as secondary crystallization. The effect of molar mass, catalyst residues, chain composition, and thermo-mechanical treatments on the crystallization kinetics, structure, and morphology of PET are also reviewed in this contribution. [ABSTRACT FROM AUTHOR]

Bulk Se90Pb10−xSnx (x = 0, 2, 4, 6, and 8) glassy alloys have been obtained by quenching technique, where x indicates the atomic mass percentage (at. mass%) of tin. The differential scanning calorimeter (DSC) technique is used under non-isothermal conditions to determine different characteristic temperatures such as the glass transition temperature Tg, on-set and peak crystallization temperatures Tc and Tp, and melting temperature Tm. The thermal stability parameter of current ternary Se90Pb10−xSnx glasses exhibits A nonlinear compositional dependence with a maximum value for x = 8 at. mass% of Sn. The mean values of the crystallization rate (< Kp >) are lowest at x = 2 and 8, suggesting that a long time is required for these two compositions to fully crystallize. As a result, their stability against devitrification is at its highest, whereas the composition containing 6 at. mass% of Sn has the highest rate of crystallization and the lowest stability against devitrification. [ABSTRACT FROM AUTHOR]

Tandem solar cells combining perovskite and silicon have witnessed rapid development in recent years. However, the top cell, utilizing wide‐bandgap perovskite as absorbers generally suffer significant open‐circuit voltage (VOC) deficit, particularly for inorganic perovskite, which poses a considerable obstacle to enhancing the power conversion efficiency (PCE). Here, a modulation strategy by using 2,6‐pyridinedicarboxamide (PC), the crystallization kinetics of inorganic perovskite film can be effectively regulated, specifically manifested as a relatively longer annealing time in the air, resulting in sufficient growth for the inorganic perovskite grains. Additionally, PC can effectively in situ passivate uncoordinated Pb2+, suppressing the non‐radiative recombination of charge carriers. Eventually, a record PCE of 22.07% is achieved based on n–i–p inorganic perovskite solar cells (IPSCs), which also demonstrate the highest VOC above 1.34 V (1.71 eV of bandgap). More importantly, the unencapsulated IPSCs show enhanced thermal stability and photostability. Furthermore, the n–i–p IPSCs are also applied to inorganic perovskite/silicon tandem solar cells (IPTSCs), a PCE of 27.27% and an impressive VOC of 2.024 V are obtained. [ABSTRACT FROM AUTHOR]

The quasi-2D Dion–Jacobson perovskite exhibits significant photophysical properties and potential applications. However, the insufficient exciton energy transfer leads to nonradiative recombination that seriously hinders charge transport. Here, an efficient energy transfer is achieved by incorporating the alkali metal, which not only constrains the nucleation of high-n phases and promotes the growth of the middle-n phases but also optimizes the phase distribution and the crystal orientation to promote carrier transport. We achieve a green amplified spontaneous emission with a low threshold of 28.5 μJ/cm2 and a vertical-cavity laser operating in a single-mode configuration with a linewidth of 0.96 nm. [ABSTRACT FROM AUTHOR]

This paper aims to study the crystallization kinetics of local bentonite taken from the Maghnia region of Algeria after conducting the toasting process to powder with different temperature degrees 200, 400, 500, 700, 800, 900, 1000°C and 1100°C. The material was examined by differential thermal analysis (DTA) at different heating rates (10–50°C/min), and X ray diffraction (XRD). We used also Infrared Spectroscopy to detect the vibrations characteristic of the chemical bonds and to analyze the molecules forming the material. Scanning electron Microscopy (SEM) has been used to investigate the bentonite microstructure revealing granules shape and distribution. We have applied Non-isothermal crystallization kinetic methods to study the mechanism of crystallization in the bentonite. After a calcinations process at 200°C and 700°C of the bentonite, X-ray diffraction data showed a decrease in the basal spacing (d001) from 12.72 Å of room temperature to about 11.98 Å and 9.93 Å respectively. We also observed the disappearance of the diffraction peaks represented by the d001 interval, which expresses the montmorillonite phase after calcination of samples at 800°C. The average activation energy has been determined by Kissinger method (221.046 kJ/mol), Ozawa method (225.557 kJ/mol) and Boswell method (229.356 kJ/mol). Growth morphology parameters and the frequency factor for the reaction of the dehydroxylation at different temperatures have been measured. [ABSTRACT FROM AUTHOR]

Polypropylene is commonly used as a binder for ceramic injection molding, and rapid cooling is often encountered during processing. However, the crystallization behavior of polypropylene shows a strong dependence on cooling rate due to its semi-crystalline characteristics. Therefore, the influence of cooling rate on the quality of final product cannot be ignored. In this study, the fast differential scanning calorimetry (FSC) test was performed to study the influence of cooling rate on the non-isothermal crystallization behavior and non-isothermal crystallization kinetics of a copolymer polypropylene (PP BC03B). The results show that the crystallization temperatures and crystallinity decrease as the cooling rate increases. In addition, two exothermic peaks occur when cooling rate ranges from 30 to 300 K·s-1, indicating the formation of another crystal phase. Avrami, Ozawa and Mo equations were used to explore the non-isothermal crystallization kinetics, and it can be concluded that the Mo method is suitable for this study. [ABSTRACT FROM AUTHOR]

Poly(ester amide)s (PEAs) have received extensive attention due to their unique chemical structure and excellent properties. In this paper, a novel PEA (P6T6T) was prepared through melt polycondensation of terephthalic acid (PTA) and 6T6‐diamide‐diol (6T6), which was from the amidation of 6‐amino‐1‐hexanol and PTA. The structures were characterized by nuclear magnetic resonance, fourier transform infrared, and wide‐angle X‐Ray diffraction, and the thermal properties were evaluated by differential scanning calorimetry and thermal gravimetric analysis for P6T6T. It was found that the melting point of P6T6T was 217°C, which was about 37°C lower than that of PET (254°C), while the initial decomposition temperature was maintained at about 381°C. P6T6T had a fast crystallization rate (the half time of crystallization (t1/2) range from 35 to 60 s) and great crystallization properties. The saturated water absorption of the P6T6T was measured to be 2.53 wt%, which was three times that of PET (0.83 wt%). Furthermore, the water contact angle of P6T6T was determined to be 57.3°C, much lower than that of PET (94.7°C). All these results suggest that the incorporation of amide was an efficient method to improve the water absorption of polyester fibers. [ABSTRACT FROM AUTHOR]

We are investigating a novel enrichment process that could allow the use of industrial complementary metal–oxide–semiconductor implanters to manufacture "quantum grade" 28Si layers for use in quantum computers. Our implanted layer exchange enrichment process leverages conventional deposition-based layer exchange approaches but replaces a step of depositing a Si layer above an Al layer with a 28Si implant into the top of an Al layer. A subsequent anneal dissolves Si into Al beneath the implanted region where Si diffuses and either epitaxially grows onto the substrate or forms poly-crystals in the Al [Schneider and England, ACS Appl. Mater. Interfaces 15, 21609 (2023)]. We have developed a qualitative model using simple assumptions and boundary conditions to estimate characteristic times and rates of epitaxy or poly-crystallization for this novel layer exchange process. We have used the model to explain crystallization outcomes reported in this paper and previously. We find that the absence of an oxide boundary layer separating Si and Al allows Si diffusion to become established within the first second of all the anneals studied and that crystallization actually completes during the temperature ramp of most of the anneals. The rapid evolution of Si supersaturation in Al beneath the implanted layer explains the ratios of epitaxial growth to poly-crystallization observed after these anneals. We use this understanding to propose the implant layer exchange conditions that could produce the highest quality mono-crystalline quantum grade Si. [ABSTRACT FROM AUTHOR]

Herein, the nanofibrillated poly(butylene succinate)/polytetrafluoroethylene (PBS/PTFE) composites were prepared. The relaxation time was prolonged by PTFE fibrils, resulting in an enhancement in storage modulus and melt viscosity. Differential scanning calorimetry was used to study the non-isothermal crystallization kinetics at different cooling rates. These results showed that PTFE fibrils could promote crystallization nucleation and excessive fibrils could inhibit crystallization growth. Lightweight PBS/PTFE composite foams were fabricated using core-back foam injection molding. Loading the PTFE fibrils increased the cell density of PBS foam from 2.7×106 to 1.4×108 cells/cm3 and improved the cell morphology of PBS foam. By controlling the foaming parameter, the tensile properties of PBS-based composite foam with 1 wt.% PTFE were improved overall, and the Izod impact strength was increased by 9–69% compared with the PBS foam. [ABSTRACT FROM AUTHOR]

Due to the hydrophobic organic cations, quasi‐two‐dimensional (quasi‐2D) lead halide perovskite materials have shown better moisture resistance. However, the inappropriate multiphase structure in the quasi‐2D perovskite films seriously affects the efficient transport of energy from low‐n domains to high‐n domains, especially when prepared in air. Herein, the study develops efficient quasi‐2D perovskite films in 30% ± 10% humidity and studies their amplified spontaneous emission (ASE) properties. It can be seen that the phase disproportionation of the quasi‐2D perovskite films prepared in air is greatly suppressed by manipulating the crystallization kinetics of the multiphase structure via using the organic additive benzimidazole (BI), thereby enabling a narrowed phase distribution. Due to the improvement in energy transfer efficiency, surface roughness, and humidity stability, the ASE with a low threshold of 13.4 µJ cm−2 is realized under the quasi‐continuous pumping condition, which is significantly <28.8 µJ cm−2 of the pristine film. Furthermore, the introduction of BI organic additive enhanced the number of peak intensity half‐decay pulses to as high as 5.6 × 107, indicating a good operating stability of the BI‐treated films. This work suggests that the BI‐treated quasi‐2D perovskite films provide the possibility for preparing high‐performance lasers in air. [ABSTRACT FROM AUTHOR]

Cerium‐based Metal‐Organic frameworks (Ce‐MOFs) are attracting increasing interest due to their similar structural features to zirconium MOFs. The redox behavior of Ce(III/IV) adds a range of properties to the compounds. Recently, perfluorinated linkers have been used in the synthesis of MOFs to introduce new characteristic into the structure. We report the synthesis and structural characterization of Ce(IV)‐based MOFs constructed using two perfluorinated alkyl linkers. Their structure, based on hexanuclear Ce6O4(OH)412+ clusters linked to each other by the dicarboxylate ions, has been solved ab‐initio from X‐ray powder diffraction data and refined by the Rietveld method. The crystallization kinetics and the MOF formation mechanism was also invesitigated by Synchrotron radiation with XAS spectroscopies (EXAFS and XANES). The MOFs present the same fcu cubic topology as observed in MOF‐801 and UiO‐66, and they showed good stability in water at different pH conditions. The electronic structure of these MOFs has been studied by DFT calculations in order to obtain insights into the density of states structure of the reported compounds, resulting in band gaps in the range of 2.8–3.1 eV. Their catalytic properties were tested both thermally and under visible light irradiation for the degradation of methyl orange (MO) dye. [ABSTRACT FROM AUTHOR]

A modified model based on classical nucleation theory was applied to a natural hydrous peraluminous pegmatite composition and tested against crystallization experiments in order to further investigate the quantification of nucleation delay in felsic melts. Crystallization experiments were performed in a piston-cylinder apparatus at 630 MPa and temperatures between 650 and 1000 °C for durations ranging from 0.3 to 211 h. Experimental run products were investigated by scanning electron microscopy paired with energy dispersive spectroscopy analyses of both crystalline and quenched liquid phases, the results of which were compared to an established theoretical nucleation delay model from the literature. The experiments showed good agreement (within a factor of 5) with the model for quartz, while it showed moderate agreement (within a factor of 10) with the model for sodic feldspar. Other crystals also nucleated, demonstrating abundant features of disequilibrium. Our research further demonstrates the potential of the model to predict nucleation delay, showing promising results for the quantification of the nucleation delay of quartz and feldspar in natural felsic melts, thus adding to previously published studies on hydrous, metaluminous, felsic melts and dry basaltic melts. [ABSTRACT FROM AUTHOR]

This paper deals with the crystallization kinetics, optical and structural features of V2−xMgxO5−δ (x = 0.15–0.30) glasses under non-isothermal conditions using Lasocka, Kissinger and Augis-Bennett approaches. Raman spectra confirm the layer structure of vanadium in the present glasses. The optical band gap decreases from 2.64 to 2.20 eV with an increase in MgO doping, while refractive index (n) increases from 2.50 to 2.65 with an increase in MgO doping. The activation energy of glass transition and crystallization increase from 150 to 229 kJ mol−1 and 256–442 kJ mol−1, respectively, with the doping of MgO in V2O5. The kinetic parameters calculated from different approaches are found to be in a good agreement with each other. The fragility index increases from 29 to 51 with increasing MgO content in place of V2O5. The values of f g and E c are found to enhance with changes in heating rates due to the strong influence of heating rates on glass transition temperature. [ABSTRACT FROM AUTHOR]

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) is a polymer obtained by bacterial fermentation that emerges as an alternative to polymers of petrochemical origin. The complex crystallization kinetics that occurs over 15 days after melting, known as ageing, limits its industrial application. During the aging process, there is a change of the degree of crystallinity, which has an effect on the chemical structure of the material. Additionally, changes in the mechanical properties, colorimetry, and dimensional shrinkage are observed. Different material properties are observed depending on the cooling conditions employed. For the ageing process, two different conditions are considered: ageing at room temperature and annealing at high temperature (60 °C). [ABSTRACT FROM AUTHOR]

The melting behavior of nanoporous‐crystalline (NC) poly(2,6‐dimethyl‐1,4‐phenylene)oxide (PPO) films is obtained by guest removal from co‐crystalline (CC) films, as crystallized by sorption at different temperatures of liquid guests exhibiting largely different molecular volumes, is discussed. For all the considered guest‐induced crystallizations, the NC α form is obtained with melting temperatures (Tm) being essentially independent of the chemical nature of the guest. Tm of α NC films, as obtained by solution casting, instead widely varies with guest molecular volume (Tm in the range 236–264°C). This difference in the melting behavior of α NC PPO films is obtained by solution casting and guest‐induced crystallization using the same guest is attributed to the kinetics of the crystallization. [ABSTRACT FROM AUTHOR]

The wide array of polydimethylsiloxane (PDMS) variants available on the market, coupled with the intricate combination of additives in silicone polymers, and the incomplete understanding of drug release behavior make formulation development of levonorgestrel intrauterine systems (LNG-IUSs) formidable. Accordingly, the objectives of this work were to investigate the impact of excipients on formulation attributes and in vitro performance of LNG-IUSs, elucidate drug release mechanisms, and thereby improve product understanding. LNG-IUSs with a wide range of additives and fillers were prepared, and in vitro drug release testing was conducted for up to 12 months. Incorporating various additives and/or fillers (silica, silicone resins, silicone oil, PEG, etc.) altered the crystallization kinetics of the crosslinked polymer, the viscosity, and the microstructure. In addition, drug-excipient interactions can occur. Interestingly, additives which increased matrix hydrophobicity and hindered PDMS crystallization facilitated dissolution and permeation of the lipophilic LNG. The influence of additives and lubricants on the mechanical properties of LNG-IUSs were also evaluated. PDMS chemical substitution and molecular weight were deemed to be most critical polymer attributes to the in vitro performance of LNG-IUSs. Drugs with varying physicochemical characteristics were used to prepare IUSs, modeling of the release kinetics was performed, and correlations between release properties and the various physicochemical attributes of the model drugs were established. Strong correlations between first order release rate constants and both drug solubility and Log P underpin the partition and diffusion-based release mechanisms in LNG-IUSs. This is the first comprehensive report to provide a mechanistic understanding of material-property-performance relationships for IUSs. This work offers an evidence-based approach to rational excipient selection and tailoring of drug release to achieve target daily release rates in vivo. The novel insights gained through this research could be helpful for supporting development of brand and generic IUS products as well as their regulatory assessment. [Display omitted] • Silicone resins form a hydrophobic amorphous matrix leading to faster drug release. • Intermolecular interactions in silica/DE increase crystallinity and mechanical strength. • Drug release from phenyl-PDMS> dimethyl-PDMS> fluoro-PDMS (increasing polarity). • Drug release from IUSs is directly proportional to API solubility in polymer and Log P. • PDMS crystallinity and drug-polymer interactions may govern matrix drug diffusivity. [ABSTRACT FROM AUTHOR]

0.75(0.4Na 2 O-0.1K 2 O-0.5Nb 2 O 5)-0.25(0.87SiO 2 -0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na 0.9 K 0.1 NbO 3 and NaNbO 3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76 μm to 1.33 μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba 2 NaNb 5 O 15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91 μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm. [ABSTRACT FROM AUTHOR]

In this study, the impact of octaphenyl polyhedral oligomeric silsesquioxane (POSS) on the thermal stability of polybenzoxazine resin at 1, 3, and 5 wt% POSS loading through dynamic thermogravimetric analysis (TGA) at heating rates of 10, 20, 30 and 40°C min−1 was investigated. Besides, the decomposition kinetics of polybenzoxazine resin (PBZ) and various nanocomposites were studied using Kissinger, Friedman, Flynn‐Wall‐Ozawa (FWO) and Coats‐Redfern (CR) models and also, the activation energies of samples were calculated. At first, benzoxazine monomer was synthesized and then nanocomposites were prepared via solution mixing method. The qualitative dispersion of nanoparticles in benzoxazine resin was examined through the utilization of scanning electron microscopy and x‐ray diffraction experiments. The results showed that the addition of nanoparticles improved the thermal stability of PBZ resin specially at 1 wt% POSS loading and at higher POSS content the thermal stability of the resin decreased. As determined by TGA, the char yield of resin was enhanced by 2.6% upon the addition of 1 wt% nanoparticles. In addition, in 1 weight percent of nanoparticles, as the heating rate rose from 10 to 40°C min−1, the Integral Program Decomposition Temperature (IPDT) has increased by about 260°C, and this increase is about 183°C compared to the resin, and also elevating the heating rate, Td (5%) and Td (10%) weight loss of samples shifted to higher temperatures. The degradation mechanism of the resin and nanocomposites was evaluated through Kissinger, Friedman, FWO and CR models. The results displayed that the addition of 1 wt% nanoparticles increased the activation energy (Ea) values of the nanocomposites compared to that of neat resin and above this filler content, the Ea values decreased. The findings derived from the FWO model indicated that the inclusion of a 1 wt% filler raised the Ea values of the first and second stages of PBZ resin decomposition from 136–200 and 151–214 kJ mol−1 to 148–210 and 180–228 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

The thermal, crystallization kinetics and hydrolysis properties of poly(lactic acid)‐based blends containing different concentrations of 5‐dimethylthioisosulfate salts (LAK) were systematically investigated and compared with those of poly(lactic acid) (PLA). PLA/LAK blends were prepared by melt blending method‐using LAK as a nucleating agent of PLA. During the isothermal crystallization process, the morphology of PLA crystal in the neat PLA and PLA/LAK blends showed spherical crystals. With an increase in the concentration of LAK, the nucleating density of the PLA spherulites increased and the size of the PLA spherulites decreased. Differential scanning calorimetry indicates that after the addition of LAK, both the crystallinity and crystallization rate of PLA have been enhanced. In situ X‐ray diffraction analysis also shows that the sample exhibits the same crystal structure as neat PLA and continues to strengthen, indicating that LAK enhances the crystallization properties of PLA. Moreover, the crystallinity of PLA increased and crystal size of PLA decreased with the increase in the LAK content. The Vicat softening temperatures of PLA/LAK blends increased, so the heat resistance improved. Through hydrolysis testing under identical conditions, the PLA/LAK blends exhibits better hydrolytic stability. [ABSTRACT FROM AUTHOR]

In this study, transparent K2O-Al2O3-SiO2 (KAS) glass-ceramics with leucite as the main crystalline phase were prepared by melting-quench method and two-step heat treatment. The effects of SiO2/Al2O3 ratio and heat treatment on crystallization and mechanical properties were studied. The crystallization kinetics and X-Ray Diffraction (XRD) results showed that SiO2/Al2O3 ratio and heat treatment system had a direct impact on the crystallization behavior of potassium aluminosilicate glass-ceramics. When heat-treated at 680 °C/2 h and 780 °C/1 h, cracks generated on the surface of the sample with the addition of SiO2/Al2O3 = 4.8 (in mol) due to the huge difference in the coefficient of thermal expansion between glass matrix and surface. When the addition of SiO2/Al2O3 (in mol) was 4, the sample with leucite as the main crystalline phase showed an excellent fracture toughness (1.46 MPa·m05) after the heat treatment of 680 °C/2 h and 780 °C/5 h. And there was a phase transformation from kaliophilite to leucite. The crystalline phases of the sample heat-treated at 680 °C/8 h and 780 °C/1 h were leucite and kaliophilite, which resulted in the visible light transmittance of 63% and the fracture toughness of 0.91 MPa·m0.5. Furthermore, after the heat treatment of 680 °C/2 h and 780 °C/5 h, the main crystalline phase of the sample with SiO2/Al2O3 = 3.2 (in mol) was still kaliophilite. Because leucite only grows on the surface of the sample and is hard to grow inward, it is hard to achieve the bulk crystallization of leucite in the sample with SiO2/Al2O3 = 3.2 (in mol). [ABSTRACT FROM AUTHOR]

Trimodal polymerization of polyethylene has become a research interest in recent years due to its excellent potential for altering material properties and overcoming the limitations of the bimodal process. Here, we have comprehensively investigated the effects of manipulating polymerization parameters, such as split value (SV), hydrogen‐to‐ethylene ratio (H2/C2), and stage switching, on the rheological, thermal, and mechanical properties of synthesized trimodal high‐density polyethylene (HDPE). The synthesized samples were obtained through three consecutive stages in a slurry lab‐scale reactor. The results of molten state analysis demonstrate that recipe modification, particularly SV and H2/C2 balancing in the second and third stages, had a dramatic effect on the rheological properties including dynamic moduli, G′‐G″ crossover, and the shear‐thinning behavior. Concurrently, improvements in physio‐mechanical properties, such as sagging behavior and slow crack growth resistance (SCG), were observed compared to the bimodal resin. The thermal characterization indicates that the polymerization adjustments made did not notably impact the thermal properties of HDPE samples (e.g., Tm), throughout the all‐recipe manipulation. However, minor fluctuations in crystallinity and crystallization kinetics were observed which was presumably attributed to the molecular weight of the final resin. Overall, in our trimodal polymerization recipe, the HDPE powder is within the specified range of particle size distribution, which ensures excellent bulk density and flowability. Highlights: Influence of polymerization parameters such as split value, H2/C2, and stage switching in properties of trimodal HDPE.HDPE resin received from split value and H2/C2 balancing have superior SCG and sagging resistance.All HDPE samples synthesized by different recipes have similar thermal properties. [ABSTRACT FROM AUTHOR]

In the paper, glass ceramics used as architectural materials were prepared based on lead fuming furnace-slag (LFFS) by a synergistic sinter-crystallization method. The effects of Al2O3 addition on the crystallization phase, crystallization kinetics, and mechanical performance of glass ceramics were investigated. The results showed that the phases of the glass ceramics prepared were composed of gehlenite and wollastonite, and crystallization kinetics analysis showed that bulk crystallization dominated the overall crystallization process in the Al2O3 content range from 2% to 8%. The glass transition temperature and the crystallization peak temperature of the glass ceramics generally increased with the increase in the Al2O3 content. Additionally, the crystalline morphology gradually developed from sheet-like to spherical, while the number of pores increased and the bulk density gradually decreased. When the Al2O3 content was 2%, the bending strength of glass ceramics reached its maximum, 75.1 MPa, corresponding to a bulk density of 2.24 g·cm−3. Owing to the high strength and relatively low bulk density, the sintered glass ceramics appear promising for potential applications in lightweight construction tiles. [ABSTRACT FROM AUTHOR]

The high density of aluminum nanocrystals (>1021 m−3) that develop during the primary crystallization in Al-based metallic glasses indicates a high nucleation rate (∼1018 m−3 s−1). Several studies have been advanced to account for the primary crystallization behavior, but none have been developed to completely describe the reaction kinetics. Recently, structural analysis by fluctuation electron microscopy has demonstrated the presence of the Al-like medium range order (MRO) regions as a spatial heterogeneity in as-spun Al88Y7Fe5 metallic glass that is representative for the class of Al-based amorphous alloys that develop Al nanocrystals during primary crystallization. From the structural characterization, an MRO seeded nucleation configuration is established, whereby the Al nanocrystals are catalyzed by the MRO core to decrease the nucleation barrier. The MRO seeded nucleation model and the kinetic data from the delay time (τ) measurement provide a full accounting of the evolution of the Al nanocrystal density (Nv) during the primary crystallization under isothermal annealing treatments. Moreover, the calculated values of the steady state nucleation rates (Jss) predicted by the nucleation model agree with the experimental results. Moreover, the model satisfies constraints on the structural, thermodynamic, and kinetic parameters, such as the critical nucleus size, the interface energy, and the volume-free energy driving force that are essential for a fully self-consistent nucleation kinetics analysis. The nucleation kinetics model can be applied more broadly to materials that are characterized by the presence of spatial heterogeneities. [ABSTRACT FROM AUTHOR]

Many phase change materials (PCMs) are found to crystallize without exhibiting a glass transition endotherm upon reheating. In this paper, we review experimental evidence revealing that these PCMs and likely other hyperquenched molecular and metallic systems can crystallize from the glassy state when reheated at a standard rate. Among these evidences, PCMs annealed below the glass transition temperature Tg exhibit slower crystallization kinetics despite an increase in the number of sub-critical nuclei that should promote the crystallization speed. Flash calorimetry uncovers the glass transition endotherm hidden by crystallization and reveals a distinct change in kinetics when crystallization switches from the glassy to the supercooled liquid state. The resulting Tg value also rationalizes the presence of the pre-Tg relaxation exotherm ubiquitous of hyperquenched systems. Finally, the shift in crystallization temperature during annealing exhibits a non-exponential decay that is characteristic of structural relaxation in the glass. Modeling using a modified Turnbull equation for nucleation rate supports the existence of sub-Tg fast crystallization and emphasizes the benefit of a fragile-to-strong transition for PCM applications due to a reduction in crystallization at low temperature (improved data retention) and increasing its speed at high temperature (faster computing). [ABSTRACT FROM AUTHOR]

Clotrimazole (CMZ) is a classical antifungal drug for studying crystallization. In this study, a new CMZ polymorph (Form 2) was discovered during the process of nucleation and growth rate determination in the melt. High-quality single crystals were grown from melt microdroplets to determine the crystal structure by x-ray diffraction. Form 2 is metastable and exhibits a disordered structure. The crystal nucleation and growth kinetics of the two CMZ polymorphs were systematically measured. Form 2 nucleates and grows faster than the existing form (Form 1). The maximum nucleation rate of Forms 1 and 2 was observed at 50 °C (1.07 Tg). The summary of the maximum nucleation rate temperature of CMZ and the other six organic compounds indicates that nucleation near Tg in the supercooled liquid is a useful approach to discovering new polymorphs. This study is relevant for the discovering new drug polymorphs through an understanding of nucleation and growth kinetics during melt crystallization. [ABSTRACT FROM AUTHOR]

Phase‐change materials (PCMs) are an important family of alloys employed in non‐volatile memories and neuromorphic devices. These devices exploit the ability of PCMs to undergo rapid transitions between amorphous and crystalline phases at moderately high temperature. At ambient conditions, both phases are stable. These properties imply a very strong temperature dependence of the crystallization kinetics, which has been attributed to the high fragility of the supercooled liquid phase. In this work, the fragility index of GeTe, an important PCM, is extracted from a computational exploration of the potential energy landscape of the system by molecular dynamics simulations. For this purpose, a neural‐network potential is used to describe the interatomic interactions, which enables the evaluation of the configurational entropy in the deeply supercooled regime. The viscosity and the relaxation times are also calculated in the same temperature range. Finally, the Adam‐Gibbs relation is used to extrapolate the data to low temperatures and estimate the glass transition temperature and the fragility index. The latter quantity turns out to be of the order of 135–140, which shows that liquid GeTe is a highly fragile system. [ABSTRACT FROM AUTHOR]

Herein origin and nucleation kinetics of transcrystalline layer (TCL) in bamboo fiber deposited with nano‐TiO2 (BF@TiO2)/polypropylene (PP) composite is studied. Firstly, the surface morphology, roughness, and energy, as well as crystalline structure (e. g., crystal face indices (hkl)) of BF@TiO2 are analyzed to clarify the origin of TCL in the composite. Subsequently, the nucleation kinetics of TCL in BF@TiO2/PP composite at different crystallization temperatures (Tc) are investigated through polarized optical microscopy. The results find that the surface roughness and energy of BF@TiO2 increase by 47.55 % and 2.41 % compared with untreated BF, respectively. Interestingly, the mismatch rates (MRs) of hkl(BF) vs. hkl(PP) are >320 %. In comparison, the MRs of (101)(BF@TiO2)TiO2 vs. (hkl)(PP) are dramatically decreased to <25 %, suggesting a similar crystal plane between BF@TiO2 and PP matrix. These results indicate that the TCL formation in the composite is more facile in BF@TiO2 than in the untreated BF. During isothermal crystallization, the nucleation and spherulite growth rates decrease as the Tc increases. The interface free energy difference (▵σ) between BF@TiO2 and PP is calculated based on the heterogeneous nucleation theory. The ▵σ is 1.54±0.11 J cm−2, highlighting that the BF@TiO2 strongly induces the PP nucleation. [ABSTRACT FROM AUTHOR]

Intermolecular interactions are critical to the crystallization of biomolecules, yet the precise control of biomolecular crystal growth based on these interactions remains elusive. To understand the connections between the crystallization kinetics and the strength of intermolecular interactions, herein we have employed DNA triangular crystals and modified ones as a versatile tool to investigate how the strength of intermolecular interaction affects crystal growth. Interestingly, we have found that the 2'‐O‐methylation at sticky ends of the DNA triangle could strengthen its intermolecular interaction, resulting in the accelerated formation of smaller crystals. Conversely, phosphorothioate modification could weaken the sticky‐end cohesion and delay the nucleation, resulting in formation of fewer but larger crystals. In addition, these modification effects were consistently observed in the crystallization of a DNA decamer. In one word, our experimental results demonstrate that the strength of intermolecular interaction directly impacts crystal growth. It suggests that 2'‐O‐methylation and phosphorothioate modification represents a rational strategy for controlling DNA molecules grow into desired crystals and it also facilitates structural determination. [ABSTRACT FROM AUTHOR]

Organic photovoltaics (OPVs) have attracted widespread attention and became an important member of clean energy. Recently, their power conversion efficiency (PCE) has surpassed 19%. As is well known, the morphology of the active layer in OPVs crucially influences the PCE. In consideration of the intricate interactions between the donor molecules and acceptor molecules, the precise control of the morphology of the active layer is extremely challenging. Hence, it is urgent to develop effective methods to fabricate the hierarchical structure of the active layer. One significant driving force for the morphological evolution of the active layer is crystallization. Therefore, regulating the crystallization kinetics is an effective strategy for morphology control. In this review, we present the kinetic strategies recently developed to highlight their significance and effectiveness in morphology control. By applying these kinetic strategies, the hierarchical structure, including phase separation, domain size, crystallinity, and molecular orientation of the active layer can be optimized in different blend systems, leading to an improved PCE of OPVs. The outcomes set the stage for future advancements in device performance. [ABSTRACT FROM AUTHOR]