Fluid gels are jammed microgel suspensions obtained by shearing a gelling hydrocolloid during its sol-gel transition. This study focused on calcium-induced low acyl gellan gum (LAGG) fluid gels and investigated the impact of calcium concentration before fluid gel formation on the resulting rheological behavior, fluid gel particle properties, and supramolecular structure. The elasticity and yield stress of fluid gels and quiescently cooled gels reached a maximum when the calcium concentration was increased from 0.78 to (approx.) 30 mmol/kg. Small angle X-ray scattering (SAXS) of fluid gels revealed a progressive increase in gel network connectivity up to the calcium concentration where the peak in rheological properties was observed followed by a less interconnected network at calcium concentrations above the peak. Furthermore, rheological measurements supplemented with free calcium and zeta-potential measurements, support that the decrease after the peak in rheological response is due to the combination of fluid gel particle softening with a decrease in surface charge. The results of this study enable to establish clearer links between rheological behavior, particle properties and supramolecular structure of calcium-induced LAGG fluid gels. This work enables a more effective design of fluid gel properties for different applications from food to pharma and biomaterials.

In this study, 10% of potato tissue dry matter in potato mashes was replaced by potato granulates, potato flakes or rice flour and/or 1.0% hydroxypropyl methylcellulose (HPMC) was added. The potato mash molecular mobility, viscoelasticity and firmness and the oil content and firmness after deep-frying were evaluated. The small particle size of potato granulates as well as HPMC's interference with the amylose network reduced the firmness. Including rice flour or potato granulates increased the portion of rigid CH protons and heterogeneity in molecular mobility of protons in highly mobile regions, thereby increasing the loss modulus and narrowing the linear viscoelastic strain range. HPMC usage reduced the oil content with 45%, but was less effective when potato flakes (25%), potato granules (15%) or rice flour (not significant) were included, probably because of interference with HPMC-water interactions. Hence, including dry starchy ingredients and HPMC allows for tailoring the (deep-fried) potato mash properties.

Spring frosts occur in many pome fruit-producing regions globally. They are highly detrimental to floral tissues and yield, making frost tolerance of the reproductive organs one of the major breeding challenges. Currently, frost tolerance of flowers and floral buds is determined by meticulous observations of frost damage symptoms, or by methods that relate the damage with the accumulation of physiologically-relevant biochemicals. These methods are often inaccurate and are only feasible in instances of severe frost. We propose differential scanning calorimetry (DSC) to assess the frost tolerance of pome fruit floral tissues by measuring the heat flow of tissue samples when passing the freezing transition. DSC was applied to floral organs isolated from recently open king flowers of the apple 'Jonagold' (Malus domestica Borkh.) and the European pear 'Conference' (Pyrus communis L.) to simulate frost and determine freezing temperature as a quantitative indicator of frost tolerance. Freezing, crystallization, and melting points were measured by cooling and heating isolated ovules, stamens, and stigmas of mature king flowers from 20 to -40 degrees C and back to 20 degrees C. In pear, tissue-specific effects were observed, with ovules showing the highest (-9.6 degrees C) and stamens showing the lowest average freezing temperature (-13.1 degrees C), indicating that stamens are less susceptible to frost. In contrast, no significant differences in frost tolerance were detected among apple organs (freezing temperature of -11.1 degrees C). This study shows that DSC is an efficient method for monitoring and evaluating frost tolerance in pome fruit floral tissues and could be utilized for high-throughput phenotyping in breeding programs.

Double binary state diagrams of the benchmark semi-crystalline conjugated polymer PBTTT and its alkoxy derivatives PBTTT-OR-R and PBTTT-(OR)(2), mixed with PC61BM, are constructed using Rapid Heat-Cool Differential Scanning Calorimetry and T-resolved synchrotron X-Ray Diffraction. The polymerization method is adapted to ensure the absence of homocouplings and obtain reliable state diagrams, supported by Flory-Huggins calculations. Co-crystallization always occurs at a 45:55 w/w% polymer:PC61BM mixing ratio. All co-crystals remain stable up to 260-280 degrees C in a wide composition range, and for the first time, it is proven that they show incongruent (peritectic) melting. The three state diagrams show one eutectic, i.e., between polymer and co-crystal in the case of PBTTT and PBTTT-OR-R, and between polymer and PC61BM for PBTTT-(OR)(2). The latter eutectic beyond 280 degrees C leads to a reversible "solid-solid" transformation with the corresponding co-crystal. Isothermal treatments, at the onset temperature of co-crystallization during non-isothermal cooling, show no loss of co-crystal quality in combination with PC61BM perfectioning for fullerene-rich PBTTT:PC61BM and PBTTT-OR-R:PC61BM mixtures, whereas PBTTT-(OR)(2):PC61BM, as well as Stille-polymerized PBTTT-OR-R:PC61BM with homocouplings, show suppression of co-crystallization with the formation of separate crystals of polymer and PC61BM. These opposing effects are explained by the state diagrams, showcasing their substantial value in selecting efficient annealing conditions.

Crystallization competition in block copolymers with two different crystallizable blocks gives rise to multiple potential crystallization pathways, of which many remain to be discovered. The isothermal crystallization kinetics of a commercial double crystallizable poly(butylene terephthalate)/poly(ethylene glycol) (PBT/PEG, 30/70 w%) multiblock copolymer was studied via fast scanning calorimetry (FSC) as well as FSC combined with synchrotron wide-angle X-ray scattering (WAXS). The crystallization rate as a function of the isothermal crystallization temperature (Tiso) exhibited two overlapping bell-shaped curves, corresponding to PBT and PEG crystallization. At the highest Tiso, only PBT crystallized. In the overlap region, where both blocks crystallized in competition, earlier PBT crystallization stimulated ensuing PEG crystallization. In contrast, earlier PEG crystallization suppressed subsequent PBT crystallization by inducing mobility restrictions. At the lowest Tiso, only PEG crystallized, leaving immobilized PBT in the amorphous state and implying that double crystalline PBT/PEG morphologies cannot be created isothermally at very low Tiso. These block copolymer findings were rationalized and complemented by comparison with the crystallization kinetics of the parent homopolymers.

Double binary state diagrams of the benchmark semi‐crystalline conjugated polymer PBTTT and its alkoxy derivatives PBTTT‐OR‐R and PBTTT‐(OR) 2 , mixed with PC 61 BM, are constructed using Rapid Heat‐Cool Differential Scanning Calorimetry and T‐resolved synchrotron X‐Ray Diffraction. The polymerization method is adapted to ensure the absence of homocouplings and obtain reliable state diagrams, supported by Flory‐Huggins calculations. Co‐crystallization always occurs at a 45:55 w/w% polymer:PC 61 BM mixing ratio. All co‐crystals remain stable up to 260‒280 °C in a wide composition range, and for the first time, it is proven that they show incongruent (peritectic) melting. The three state diagrams show one eutectic , i.e., between polymer and co‐crystal in the case of PBTTT and PBTTT‐OR‐R, and between polymer and PC 61 BM for PBTTT‐(OR) 2 . The latter eutectic beyond 280 °C leads to a reversible “solid‐solid” transformation with the corresponding co‐crystal. Isothermal treatments, at the onset temperature of co‐crystallization during non‐isothermal cooling, show no loss of co‐crystal quality in combination with PC 61 BM perfectioning for fullerene‐rich PBTTT:PC 61 BM and PBTTT‐OR‐R:PC 61 BM mixtures, whereas PBTTT‐(OR) 2 :PC 61 BM, as well as Stille‐polymerized PBTTT‐OR‐R:PC 61 BM with homocouplings, show suppression of co‐crystallization with the formation of separate crystals of polymer and PC 61 BM. These opposing effects are explained by the state diagrams, showcasing their substantial value in selecting efficient annealing conditions.

Black-phase cesium lead iodide (CsPbI3) is a promising candidate for high-efficiency perovskite optoelectronics, but its instability under ambient conditions remains a major challenge. Among several strategies, dimethylammonium iodide (DMAI) has emerged as a potential stabilizer; however, inconsistencies in phase stability (3-7 days) and lower solar power conversion efficiencies (∼20 vs ∼27% for hybrid perovskites) highlight the need for further improvements. This study not only demonstrates enhanced stabilization of the high-symmetry black phase of CsPbI3 and improved film morphology through optimized composition and annealing conditions but also more importantly provides detailed mechanistic insights obtained from comprehensive experimental and theoretical analyses. Systematic tuning of the DMAI concentration (1.2 M), annealing temperature (200 °C, 1 min), and Cs+ substitution (12-15%) significantly extends phase stability to 7 days under ambient conditions (35-52% relative humidity) and maintains stability even after 16 months in a drybox environment by reducing orthorhombic strain and octahedral tilting. Additionally, a minor (∼5%) zero-dimensional (0D) Cs4PbI6 phase fills pinholes, enhancing the film quality. Optimized photodiodes exhibit a low dark current (∼1 μA/cm2), high external quantum efficiency (∼80% at -2 V), and a ≥100 dB linear dynamic range. These findings provide mechanistic insights into the stabilization of the black phase of CsPbI3, advancing the development of more stable and efficient perovskite-based optoelectronic devices.

This study investigates the molecular structure, crystallization behavior, melting characteristics, and morphology of a segmented block copolymer made from crystallizable poly(1,4-cyclohexylidene cyclohexane-1,4-dicarbox-ylate) (PCCD) and soft polytetrahydrofuran (PTHF-1000) blocks. The polymer is the main component of the commercially available Amphora SP1621 powder, designed for additive manufacturing via laser sintering. Block length distributions were computed through simulations, incorporating NMR data for the monomeric content and Gel Permeation Chromatography for the molecular weight distribution. Fast Scanning Chip calorimetry confirmed the melt miscibility of the PCCD and PTHF blocks. Differential Scanning Calorimetry (DSC), coupled with optical and atomic force microscopy, as well as time-resolved synchrotron small-angle (SAXS) and wideangle X-ray diffraction (WAXS), revealed that the material crystallizes as spherulites when cooled at 10 K/ min. Primary PCCD crystallization creates intraspherulitic amorphous regions, which later undergo secondary crystallization, forming randomly oriented semicrystalline stacks. A new SAXS data interpretation method was introduced to quantify the fractions of the different stack types, aligning the overall SAXS crystallinity with the WAXS and DSC results. The thickness of the crystalline PCCD lamellae correlated with the most probable PCCD block length. By combining DSC data with the WAXS-derived crystallinity, an equation for the transition enthalpy of fully crystalline PCCD was derived. Crystallographic analysis of an oriented, injection-molded sample showed that the PCCD segments align perpendicularly to the lamellar surface and pack at a crystalline density of 1.40 g/cm3.

This study examines the temperature-resolved, polymorph-specific crystallinity of poly(lactic acid), PLA, during cooling and heating at 10 °C/min, with a focus on the effects of N, N-bis(benzoyl) hexanedioic acid dihydrazide (BHAD, commercially known as TMC306) as nucleating agent and PEG 1000 as plasticizer. A semicrystalline (PLA-1) and amorphous (PLA-2) PLA grade were investigated. The study emphasizes the importance of using temperature-dependent, polymorph-specific transition enthalpies to accurately calculate crystallinities from Differential Scanning Calorimetry (DSC). Polymorphism is independently confirmed using Wide Angle X-ray Diffraction (WAXD). Pure PLA-1 reached an α′ crystallinity of 2% during cooling, which increased to 38% through cold crystallization upon heating. At BHAD concentrations of at least 0.4%, α crystallites formed instead of α′, reaching a maximum crystallinity of 38% during cooling. The addition of 10 wt% PEG to PLA-1 facilitated primary α crystallization during cooling, followed by secondary intraspherulitic α′ crystallization upon heating, resulting ultimately in a crystallinity of 34%. Adding 1 wt% BHAD into PLA-1 with 10 wt% PEG shifted the crystallization temperature upward by 40 °C and enhanced the α crystallinity to 44%, highlighting the synergistic effect of PEG and BHAD on crystallization.

Poly(2-alkyl/aryl-2-oxazoline)s (PAOx) are biocompatible polymers that are increasingly being applied in the biomedical field. Understanding their properties is crucial to rationally applying them in the said field. Despite this increasing interest, many fundamental properties of PAOx, such as the semicrystalline nature of poly(2-n-propyl-2-oxazoline) (PnPrOx) have not been fully elucidated yet, especially for higher molar mass polymers. In the present work, the crystallinity of PnPrOx was studied by using modulated DSC as well as small-angle and wide-angle X-ray scattering. This study reveals that high molar mass PnPrOx show a much richer phase behavior than their amorphous low molar mass counterparts. For instance, aqueous solutions turn cloudy upon prolonged exposure to high temperature due to crystallization of the phase-separated high polymer concentration mesoglobules. Moreover, dry solid samples display polymorphisms as well as multiple melting behavior due to the presence of different crystal sizes and overlapping crystallization and melting events. This work suggests that additional research into the semicrystalline properties of other higher molar mass PAOx might be required to evaluate whether they have similar behavior to higher molar mass PnPrOx. Additionally, the results presented in this paper will allow for the rational development and design of pharmaceutical formulations containing PAOx, as it elucidates some of their fundamental properties.

Starch is the main source of dietary energy for humans. In order to understand the mechanisms governing native starch in vitro digestion, digestion data for six starches [wheat, maize, (waxy) maize, rice, potato and pea] of different botanical sources were fitted with the most common first-order kinetic models, i.e. the single, sequential, parallel and combined models. Parallel and combined models provided the most accurate fits and showed that all starches studied except potato starch followed a biphasic in vitro digestion pattern. The biological relevance of the kinetic parameters was explored by determining changes in crystallinity and molecular structure of the undigested starch residues during in vitro digestion. While the crystallinity of the undigested potato starch residues did not change substantially, a respectively small and large decrease in their amylose content and chain length during in vitro digestion was observed, indicating that amylose was digested slightly preferentially over amylopectin in native starch. However, the molecular structure of the starch residues changed too slowly and/or only to an insufficient extent to relate it to the kinetic parameters of the digested fractions predicted by the models. Such parameters thus need to be interpreted with caution, as their biological relevance still needs to be proven.

C14-alkoxy/alkyl PBTTT-OR-R, a derivative of the prototype PBTTT polymer, is relevant for optoelectronic applications because it combines PBTTT-like intercalation behavior with enhanced charge-transfer absorption at longer wavelengths. Additionally, fundamental insights are achieved by comparing this alternating conjugated polymer in the presence and absence of homocoupling defects. While the homocoupling-free oxidative variant, PBTTT-OR-R(O), as well as the Stille polymer with 19% homocoupling defects, PBTTT-OR-R(S), can both form co-crystals when stoichiometrically mixed with PC61BM, the co-crystal of the latter shows properties which are highly dependent on the thermal processing conditions because of the presence of these defects. The PBTTT-OR-R(S):PC61BM co-crystal shows a low thermal stability and PC61BM can progressively be expelled upon heating. In cooling from the melt and depending on the cooling rate, mixtures of PBTTT-OR-R(S) and PC61BM show a competition between co-crystallization (fast cooling) and separate crystallization (slow cooling). The PBTTT-OR-R(O):PC61BM co-crystal is much more stable up to at least 260 degrees C and is not influenced by the applied cooling rate. These findings also translate to the device level. The performance of PBTTT-OR-R:PC61BM photodiodes is severely deteriorated after isothermal annealing in case of PBTTT-OR-R(S), whereas the thermally robust co-crystals of PBTTT-OR-R(O) allow a more flexible design of optimized devices. PBTTT-OR-R, a C14-alkoxy/alkyl-PBTTT polymer derivative, is of substantial interest for optoelectronics due to its specific fullerene intercalation behavior and enhanced charge-transfer absorption. Comparing this polymer with (S) and without (O) homocoupling defects reveals that PBTTT-OR-R(O) forms stable co-crystals with PC61BM, while PBTTT-OR-R(S) exhibits thermal instability, affecting photodiode performance after annealing. image

Questions about the origin of the adsorption/desorption hysteresis in mesoporous materials are as old as sorption experiments themselves. The historical conception that underlines most existing methods to extract pore size distributions from sorption data assumes that adsorption is a metastable process and that desorption takes place at thermodynamic equilibrium. In this work, we measure nitrogen and argon sorption on a series of 14 SBA-15 ordered mesoporous silicas and use small-angle X-ray scattering to independently determine their pore sizes. We find that capillary condensation systematically occurs close to thermodynamic equilibrium according to a Derjaguin-Broekhoff-de Boer calculation. Our analysis suggests that many earlier works have significantly underestimated the actual pore size in SBA-15 materials. It also highlights the critical role of the reference isotherm used to calibrate the fluid-solid interaction in the models.

Numerous applications of nanoporous materials require their pores to be filled with liquids. In spite of its huge technological importance, the conditions for the wetting of nanometer-sized pores and its phenomenology are still poorly understood. We report on capillary rise experiments with water in carbon xerogels, with synchrotron small-angle scattering used to follow the process in situ at the nanometer scale. The data reveal a two-step wetting process whereby water permeates first into molecular-sized micropores, which is followed by the imbibition of larger mesopores. A Cassie-Baxter analysis shows that the presence of water in the micropores is central, as it turns the mesopores from being hydrophobic to hydrophilic. Based on the so-calculated contact angles, the mesopore wetting kinetics are found to be quantitatively described by a classical Washburn model. Modeling of the experimental water profile ahead of the Washburn front reveals strong surface barriers opposing water transfer from the mesopores to the micropores.

The true structure of alternating conjugated polymers-the state-of-the-art materials for many organic electronics-often deviates from the idealized picture. Homocoupling defects are in fact inherent to the widely used cross-coupling polymerization methods. Nevertheless, many polymers still perform excellently in the envisaged applications, which raises the question if one should really care about these imperfections. This article looks at the relevance of chemical precision (and lack thereof) in conjugated polymers covering the entire spectrum from the molecular scale, to the micro and mesostructure, up to the device level. The different types of polymerization errors for the alkoxylated variant of the benchmark (semi)crystalline polymer poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) are identified, visualized, and quantified and a general strategy to avoid homocoupling is introduced. Through a combination of experiments and supported by simulations, it is shown that these coupling defects hinder fullerene intercalation and limit device performance as compared to the homocoupling-free analog. This clearly demonstrates that structural defects do matter and should be generally avoided, in particular when the geometrical regularity of the polymer is essential. These insights likely go beyond the specific PBTTT derivatives studied here and are of general relevance for the wider organic electronics field.

Differences in derivatization patterns (using a fluorescent reagent, fluorescein isothiocyanate) of wheat, pea, and potato starches between native granular (NAT) starches and their respective annealed (ANN) and heat-moisture treated (HMT) starches were investigated to reveal structural changes associated with starch hydrothermal treatments. Size-exclusion chromatography with fluorescence and refractive index detection assessed the reactivity of amylose (AM), intermediate chains (IM1 and IM2), and amylopectin branch chains (AP1, AP2, and AP3) within the different starches. Shifts in X-ray diffraction patterns of HMT starches and in the gelatinization properties of both ANN and HMT starches confirmed molecular rearrangement. The reaction homogeneity (wheat and pea) and the overall extent of reaction (pea and potato) increased for HMT starches compared to other starches. The lower reactivities of IM2 chains (HMT starch) and AP3 chains (ANN starch) relative to NAT starches, indicated their involvement in molecular rearrangements and improved double helical order. IM2 and AP branch chains in ANN pea starch also were less reacted than NAT starch chains, suggesting their co-crystallization. Molecular rearrangements in ANN and HMT starches led to altered swelling and pasting viscosities. Thus, changes in the relative crystallinity of individual starch branch chains induced by hydrothermal processing impact the final physical properties.

This paper addresses the role of memory effects from earlier thermal protocols on the non-isothermal crystallization behavior of polyamide 12 (PA12). It turns out that memory effects can induce differences in crystallization temperatures as large as 30 degrees C when cooled from the melt at 10 degrees C/min. DSC experiments reveal that memory effects in PA12 result from (1) self-nucleation by the action of crystalline residues (self-seeding), (2) chemical post-condensation, and (3) polymer chain disentangling and re-entangling. Self nucleation and disentangling facilitate crystallization, while melt post condensation and re-entangling hamper it. It was demonstrated that repeated crystallization stimulates disentangling and that re entangling in the liquid state proceeds more rapidly the higher the temperature. Effects due to solid-state post-condensation are very intriguing and particularly relevant to laser sintering based additive manufacturing. It was observed that solid-state post-condensation at 175 degrees C for 1 h negatively affects crystallization in a subsequent heating/cooling cycle but that solid-state annealing at 175 degrees C for 20 h leads to an enhanced crystal perfection and chain rearrangements whose non-crystalline self-nucleating remnants in the melt at 240 degrees C need more than 1 h to relax and no longer stimulate crystallization during cooling. Importantly, 240 degrees C is higher than the equilibrium melting temperature of PA12.

The true structure of alternating conjugated polymers – the state-of-the-art materials for a number of organic electronics technologies – often deviates from the idealized picture but this gets relatively limited attention. Here, we quantify the amount of homocoupling defects resulting from Stille polymerization and shed new light on the actual distribution of these structural defects in a prototype polymer material. Further, when compared to a homocoupling-free variant, these defects hinder fullerene intercalation, with a clear implication on charge-transfer absorption. This demonstrates that molecular defects may (strongly) impact polymer and blend properties and calls for increased attention for defect-free materials.

It is well documented that most bituminous binders contain crystallisable material. This crystallisable fraction, often referred to as paraffinic or natural wax, is associated with the bitumen’s origin and has an influence on its rheological performance. In the literature, Differential Scanning Calorimetry (DSC) is the primary technique used to determine the melting and crystallisation behaviour of this waxy fraction. However, in bitumen, thermal transitions in DSC are typically very broad and can be combined with recrystallisation effects upon reheating. This work explores the potential crystallisation and melting process of a waxy and a wax-free bitumen via three different approaches: DSC, Wide-Angle X-ray Diffraction (WAXD) and Confocal Laser Scanning Microscopy (CLSM). The findings reveal that the DSC transitions of the waxy bitumen are in good agreement with the corresponding occurrence of WAXD signals and to some extent with the formation and disappearance of the surface microstructures which were followed at two cooling and heating rates. WAXD results additionally demonstrate that the crystalline material in bitumen is organised in an orthorhombic unit cell, typical for straight chain aliphatic structures. On the other hand, DSC and WAXD support the lack of crystallinity for the wax-free bitumen which could explain its featureless CLSM surface. Overall, the originality of this work resides in the disclosure of connections between crystallographic properties, thermal transitions and the surface micromorphology of bitumen.