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1.
Macromol Rapid Commun ; 44(1): e2200292, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35578983

RESUMEN

This study reports the exploration of a solvent-free supramolecular templated synthesis strategy toward highly core-cross-linked star-shaped polymers (CSPs). To achieve this, a kind of cross-linkable giant surfactant, based on a functionalized polyhedral oligomeric silsesquioxanes (POSS) head tethered with a diblock copolymer tail containing reactive benzocyclobutene groups, is designed and prepared. By varying the volume fraction of linear block copolymer tail, these giant surfactants can self-assemble into a body-centered cubic (BCC) structure in bulk, in which the supramolecular spheres are composed of a core of POSS cages, a middle shell of crosslinkable poly(4-vinylbenzocyclobutene) (PBCB) blocks, and a corona of inert polystyrene (PS) blocks. The solvent-free thermally induced cross-linking reaction of the benzocyclobutene groups can be finished in 5 min upon heating, resulting in well-defined polymeric spheres with over 90 linear chains surrounding the cross-linked cores. The outer PS blocks serve as the protection corona to ensure that cross-linking of giant surfactants occurs in each supramolecular spherical domain. Given the modular design and diversity of the POSS-based giant surfactants, it is believed that the strategy may enable access to a wide range of CSPs.


Asunto(s)
Polímeros , Tensoactivos , Polímeros/química , Solventes
2.
Neuroimage ; 264: 119766, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36435344

RESUMEN

Predictions, the bridge between the internal and external worlds, are established by prior experience and updated by sensory stimuli. Responses to omitted but unexpected stimuli, known as omission responses, can break the one-to-one mapping of stimulus-response and can expose predictions established by the preceding stimulus built up. While research into exogenous predictions (driven by external stimuli) is often reported, that into endogenous predictions (driven by internal percepts) is rarely available in the literature. Here, we report evidence for endogenous predictions established by the Zwicker tone illusion, a phantom pure-tone-like auditory percept following notch noises. We found that MMN, P300, and theta oscillations could be recorded using an omission paradigm in subjects who can perceive Zwicker tone illusions, but could not in those who cannot. The MMN and P300 responses relied on attention, but theta oscillations did not. In-depth analysis shows that an increase in single-trial theta power, including total and induced theta, with the endogenous prediction, is lateralized to the left frontal brain areas. Our study depicts that the brain automatically analyzes internal perception, progressively establishes predictions and yields prediction errors in the left frontal region when a violation occurs.


Asunto(s)
Ilusiones , Humanos , Ilusiones/fisiología , Sonido , Atención/fisiología , Corteza Cerebral/fisiología , Lóbulo Frontal/fisiología , Estimulación Acústica , Percepción Auditiva/fisiología , Electroencefalografía , Potenciales Evocados Auditivos/fisiología
3.
Med Sci Monit ; 28: e933848, 2022 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-35194010

RESUMEN

BACKGROUND This retrospective study from 2 centers in Beijing, China aimed to assess the safety and efficacy of endoscopic radiofrequency therapy under direct vision in 59 patients with gastroesophageal reflux disease (GERD) using the gastroesophageal reflux disease questionnaire (GerdQ). MATERIAL AND METHODS Fifty-nine GERD patients who underwent endoscopic radiofrequency treatment were included. Patients were divided into 2 groups: the endoscopic radiofrequency therapy under direct vision group and the non-direct vision radiofrequency therapy group. Indicators such as GerdQ score, lower esophageal sphincter (LES) pressure, DeMeester score, acid exposure time, and proton pump inhibitors (PPIs) use were collected before and after radiofrequency treatment. Postoperative complications were also recorded. The efficacy and safety of endoscopic radiofrequency therapy under direct vision were evaluated by comparing the indicators of patients in the 2 groups. RESULTS At 3 months after radiofrequency treatment, patients in the endoscopic radiofrequency therapy under direct vision group improved significantly in GerdQ score, decreased from 11.0 (10.0, 12.0) to 6.0 (6.0, 8.0), better than patients in the non-direct vision radiofrequency therapy group, and the better improvements remained at 12 months after the procedure (P<0.05). At 6 months after treatment, patients in the endoscopic radiofrequency therapy under direct vision group had significant improvements in LES pressure, which increased from 8.15 (3.18, 12.88) mmHg to 15.20 (10.25, 27.03) mmHg (P<0.05). There were no severe complications in our trial. CONCLUSIONS When compared with non-visualized endoscopic radiofrequency therapy, treatment under direct vision was safer and improved the GerdQ score and LES pressure at up to 12 months.


Asunto(s)
Reflujo Gastroesofágico/terapia , Terapia por Radiofrecuencia/métodos , Encuestas y Cuestionarios , Beijing/epidemiología , Endoscopía Gastrointestinal/métodos , Femenino , Estudios de Seguimiento , Reflujo Gastroesofágico/diagnóstico , Reflujo Gastroesofágico/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos
4.
Chemistry ; 27(30): 7992-7997, 2021 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-33830540

RESUMEN

Achieving self-assembled nanostructures with ultra-small feature sizes (e. g., below 5 nm) is an important prerequisite for the development of block copolymer lithography. In this work, the preparation and self-assembly of a series of giant molecules composed of vinyl polyhedral oligomeric silsesquioxane (VPOSS) tethered with monodispersed oligo(L-lactide) chains are presented. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) results demonstrate that ultra-small domain sizes (down to 3 nm) of phase separated lamellar morphology are achieved in bulk, driven by the strong tendency and fast kinetics for crystallization of VPOSS moieties. Moreover, upon gamma ray radiation, VPOSS cages in the lamellar structure can be crosslinked via polymerization of the vinyl groups. After pyrolysis at high temperature, ultra-thin two-dimensional nano-silica sheets can be obtained.

5.
Angew Chem Int Ed Engl ; 57(28): 8493-8497, 2018 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-29697893

RESUMEN

The graft-through synthesis of Janus graft block copolymers (GBCPs) from branched macromonomers composed of various combinations of homopolymers is presented. Self-assembly of GBCPs resulted in ordered nanostructures with ultra-small domain sizes down to 2.8 nm (half-pitch). The grafted architecture introduces an additional parameter, the backbone length, which enables control over the thermomechanical properties and processability of the GBCPs independently of their self-assembled nanostructures. The simple synthetic route to GBCPs and the possibility of using a variety of polymer combinations contribute to the universality of this technique.

6.
J Org Chem ; 81(10): 4347-52, 2016 05 20.
Artículo en Inglés | MEDLINE | ID: mdl-27096728

RESUMEN

Ladder-type conjugated molecules with a low band gap and low LUMO level were synthesized through an N-directed borylation reaction of pyrazine-derived donor-acceptor-donor precursors. The intramolecular boron-nitrogen coordination bonds played a key role in rendering the rigid and coplanar conformation of these molecules and their corresponding electronic structures. Experimental investigation and theoretical simulation revealed the dynamic nature of such coordination, which allowed for active manipulation of the optical properties of these molecules by using competing Lewis basic solvents.

7.
World J Gastrointest Endosc ; 16(1): 18-28, 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38313462

RESUMEN

BACKGROUND: The incidence and mortality rate of colorectal cancer progressively increase with age and become particularly prominent after the age of 50 years. Therefore, the population that is ≥ 50 years in age requires long-term and regular colonoscopies. Uncomfortable bowel preparation is the main reason preventing patients from undergoing regular colonoscopies. The standard bowel preparation regimen of 4-L polyethylene glycol (PEG) is effective but poorly tolerated. AIM: To investigate an effective and comfortable bowel preparation regimen for hospitalized patients ≥ 50 years in age. METHODS: Patients were randomly assigned to group 1 (2-L PEG + 30-mL lactulose + a low-residue diet) or group 2 (4-L PEG). Adequate bowel preparation was defined as a Boston bowel preparation scale (BBPS) score of ≥ 6, with a score of ≥ 2 for each segment. Non-inferiority was prespecified with a margin of 10%. Additionally, the degree of comfort was assessed based on the comfort questionnaire. RESULTS: The proportion of patients with a BBPS score of ≥ 6 in group 1 was not significantly different from that in group 2, as demonstrated by intention-to-treat (91.2% vs 91.0%, P = 0.953) and per-protocol (91.8% vs 91.0%, P = 0.802) analyses. Furthermore, in patients ≥ 75 years in age, the proportion of BBPS scores of ≥ 6 in group 1 was not significantly different from that in group 2 (90.9% vs 97.0%, P = 0.716). Group 1 had higher comfort scores (8.85 ± 1.162 vs 7.59 ± 1.735, P < 0.001), longer sleep duration (6.86 ± 1.204 h vs 5.80 ± 1.730 h, P < 0.001), and fewer awakenings (1.42 ± 1.183 vs 2.04 ± 1.835, P = 0.026) than group 2. CONCLUSION: For hospitalized patients ≥ 50 years in age, the bowel preparation regimen comprising 2-L PEG + 30-mL lactulose + a low-residue diet produced a cleanse that was as effective as the 4-L PEG regimen and even provided better comfort.

8.
Adv Mater ; : e2403830, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38848548

RESUMEN

Flexoelectricity features the strain gradient-induced mechanoelectric conversion using materials not limited by their crystalline symmetry, but state-of-the-art flexoelectric materials exhibit very small flexoelectric coefficients and are too brittle to withstand large deformations. Here, inspired by the ion polarization in living organisms, this paper reports the giant iontronic flexoelectricity of soft hydrogels where the ion polarization is attributed to the different transfer rates of cations and anions under bending deformations. The flexoelectricity is found to be easily regulated by the types of anion-cation pairs and polymer networks in the hydrogel. A polyacrylamide hydrogel with 1 m NaCl achieves a record-high flexoelectric coefficient of ≈1160 µC m-1, which can even be improved to ≈2340 µC m-1 by synergizing with the effects of ion pairs and extra polycation chains. Furthermore, the hydrogel as flexoelectric materials can withstand larger bending deformations to obtain higher polarization charges owing to its intrinsic low modulus and high elasticity. A soft flexoelectric sensor is then demonstrated for object recognition by robotic hands. The findings greatly broaden the flexoelectricity to soft, biomimetic, and biocompatible materials and applications.

9.
Front Med (Lausanne) ; 11: 1327882, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38327705

RESUMEN

Purpose: Laparoscopic partial nephrectomy (LPN) remains the most commonly used measure for treating localized renal cell cancer (RCC) with an increasing incidence of RCC ever since the 1990s. This study aimed to identify risk factors that affect the postoperative time of drainage and total drainage volume after LPN. Method: The clinical data of 612 RCC patients who received LPN from January 2012 to December 2022 in our hospital, including the postoperative drainage time and total drainage volume, were retrospectively analyzed. Univariable and multivariable linear regression and correlation analyses were used to identify the correlations between 21 factors, which include gender, age, history of alcohol consumption, family history of RCC, body weight, body mass index (BMI), and operation time, postoperative drainage time, and total drainage volume. Results: The mean time of drainage was 3.52 ± 0.71 days (range: 2 to 8 days), with an average total drainage volume of 259.83 ± 72.64 mL (range: 50 to 620 mL). Both univariable and multivariable linear regression analyses revealed several statistically significant associations. Gender (p = 0.04), age (p = 0.008), smoking history (p < 0.001), diabetes (p = 0.032), operation time (p = 0.014), and BMI (p = 0.023) were identified as significant factors associated with the time of drainage. On the other hand, age (p = 0.008), smoking history (p < 0.001), diabetes (p = 0.006), and BMI (p = 0.016) emerged as independent risk factors influencing the total drainage volume. Conclusion: The duration of postoperative drainage was found to be associated with gender, age, smoking history, diabetes, operation time, and BMI. In contrast, the total drainage volume was primarily influenced by age, smoking history, diabetes, and high BMI following LPN. For patients with these conditions, meticulous attention to hemostasis and bleeding control is crucial during the perioperative period.

10.
Technol Health Care ; 31(5): 1875-1886, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36970927

RESUMEN

BACKGROUND: At present, there are few studies related to mean nocturnal baseline impedance (MNBI), esophageal dynamic reflux monitoring, high-resolution esophageal manometry (HRM) parameter indexes, and its diagnostic value in gastroesophageal reflux disease (GERD). OBJECTIVE: To analyze the factors influencing MNBI and examine the diagnostic value of MNBI in GERD. METHODS: A retrospective analysis on 434 patients with typical reflux symptoms who underwent gastroscopy, 24-hour multichannel intraluminal impedance and pH monitoring (MII/pH) and HRM. They were divided into the conclusive evidence group (103 cases), borderline evidence group (229 cases), and exclusion evidence group (102 cases) according to the level of diagnostic evidence of GERD based on the Lyon Consensus. We analyzed the differences in MNBI, esophagitis grade, MII/pH and HRM index among the groups; the correlation between MNBI and the above indexes and its influence on MNBI; and to evaluate the diagnostic value of MNBI in GERD. RESULTS: There were significant differences in MNBI, Acid Exposure Time (AET) 4%, DeMeester score, and total reflux episodes among the three groups (P< 0.001). EGJ contractile integral (EGJ-CI) of the conclusive evidence group and the borderline evidence group was significantly lower than that in the exclusion evidence group (P< 0.001). MNBI was significantly and negatively correlated with age, BMI, AET 4%, DeMeester score, total reflux episodes, EGJ classification, esophageal motility abnormalities, and esophagitis grade (all P< 0.05), and significantly and positively correlated with EGJ-CI (P< 0.001). Age, BMI, AET 4%, EGJ classification, EGJ-CI, and esophagitis grade had significant effects on MNBI (P< 0.05); MNBI was used to diagnose GERD with a diagnostic cutoff of 2061 Ω, and AUC was 0.792 (sensitivity 74.9%, specificity 67.4%); MNBI was used to diagnose exclusion evidence group with a diagnostic cutoff of 2432 Ω, AUC was 0.774 (sensitivity 67.6%, specificity 72%). CONCLUSION: AET, EGJ-CI, and esophagitis grade are the most important influence factors of MNBI. MNBI has good diagnostic value in identifying conclusive GERD.


Asunto(s)
Esofagitis , Reflujo Gastroesofágico , Humanos , Estudios Retrospectivos , Impedancia Eléctrica , Reflujo Gastroesofágico/diagnóstico
11.
Research (Wash D C) ; 6: 0154, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37250953

RESUMEN

Regular exercise paves the way to a healthy life. However, conventional sports events are susceptible to weather conditions. Current motion sensors for home-based sports are mainly limited by operation power consumption, single-direction sensitivity, or inferior data analysis. Herein, by leveraging the 3-dimensional printing technique and triboelectric effect, a wearable self-powered multidimensional motion sensor has been developed to detect both the vertical and planar movement trajectory. By integrating with a belt, this sensor could be used to identify some low degree of freedom motions, e.g., waist or gait motion, with a high accuracy of 93.8%. Furthermore, when wearing the sensor at the ankle position, signals generated from shank motions that contain more abundant information could also be effectively collected. By means of a deep learning algorithm, the kicking direction and force could be precisely differentiated with an accuracy of 97.5%. Toward practical application, a virtual reality-enabled fitness game and a shooting game were successfully demonstrated. This work is believed to open up new insights for the development of future household sports or rehabilitation.

12.
Chem Commun (Camb) ; 59(91): 13535-13550, 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-37877745

RESUMEN

High entropy oxides (HEOs) have gained significant attention in multiple research fields, particularly in reversible energy storage. HEOs with rock-salt and spinel structures have shown excellent reversible capacity and longer cycle spans compared to traditional conversion-type anodes. However, research on HEOs and their electrochemical performance remains at an early stage. In this highlight, we review recent progress on HEO materials in the field of lithium-ion batteries (LIBs). Firstly, we introduce the synthesis methods of HEOs and some factors that affect the morphology and electrochemical properties of the synthesized materials. We then elaborate on the structural evolution of HEOs with rock-salt and spinel structures in lithium energy storage and summarize the relationship between morphology, pseudocapacitance effect, oxygen vacancy, and electrochemical performance. In the end, we give the challenges of HEO anodes for LIBs and present our opinions on how to guide the further development of HEOs for advanced anodes.

13.
Nat Commun ; 14(1): 3245, 2023 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-37277342

RESUMEN

Producing functional soft fibers via existing spinning methods is environmentally and economically costly due to the complexity of spinning equipment, involvement of copious solvents, intensive consumption of energy, and multi-step pre-/post-spinning treatments. We report a nonsolvent vapor-induced phase separation spinning approach under ambient conditions, which resembles the native spider silk fibrillation. It is enabled by the optimal rheological properties of dopes via engineering silver-coordinated molecular chain interactions and autonomous phase transition due to the nonsolvent vapor-induced phase separation effect. Fiber fibrillation under ambient conditions using a polyacrylonitrile-silver ion dope is demonstrated, along with detailed elucidations on tuning dope spinnability through rheological analysis. The obtained fibers are mechanically soft, stretchable, and electrically conductive, benefiting from elastic molecular chain networks via silver-based coordination complexes and in-situ reduced silver nanoparticles. Particularly, these fibers can be configured as wearable electronics for self-sensing and self-powering applications. Our ambient-conditions spinning approach provides a platform to create functional soft fibers with unified mechanical and electrical properties at a two-to-three order of magnitude less energy cost under ambient conditions.

14.
ACS Macro Lett ; 12(6): 738-744, 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37195258

RESUMEN

Although in Nature sequence control is widely adopted to tune the structure and functions of biomacromolecules, it remains challenging and largely unexplored in synthetic macromolecular systems due to the difficulties in a precision synthesis, which impedes the understanding of the structure-property relationship in macromolecular sequence isomerism. Herein, we report the sequence-controlled macromolecular self-assembly enabled by a pair of rationally designed isomeric dendritic rod-like molecules. With an identical chemical formula and molecular topology, the molecular solid angle of the dendron isomers was determined by the sequence of the rod building blocks tethered with side chains of different lengths. As a result, entirely different supramolecular motifs of discs and spheres were generated, which were further packed into a hexagonally packed cylinder phase and a dodecagonal quasicrystalline sphere phase, respectively. Given the efficient synthesis and modular structural variations, it is believed that the sequence-isomerism-controlled self-assembly in dendritic rod-like molecules might provide a unique avenue toward rich nanostructures in synthetic macromolecules.

15.
Nanomicro Lett ; 14(1): 86, 2022 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-35352206

RESUMEN

The pursuit to mimic skin exteroceptive ability has motivated the endeavors for epidermal artificial mechanoreceptors. Artificial mechanoreceptors are required to be highly sensitive to capture imperceptible skin deformations and preferably to be self-powered, breathable, lightweight and deformable to satisfy the prolonged wearing demands. It is still struggling to achieve these traits in single device, as it remains difficult to minimize device architecture without sacrificing the sensitivity or stability. In this article, we present an all-fiber iontronic triboelectric mechanoreceptor (ITM) to fully tackle these challenges, enabled by the high-output mechano-to-electrical energy conversion. The proposed ITM is ultralight, breathable and stretchable and is quite stable under various mechanical deformations. On the one hand, the ITM can achieve a superior instantaneous power density; on the other hand, the ITM shows excellent sensitivity serving as epidermal sensors. Precise health status monitoring is readily implemented by the ITM calibrating by detecting vital signals and physical activities of human bodies. The ITM can also realize acoustic-to-electrical conversion and distinguish voices from different people, and biometric application as a noise dosimeter is demonstrated. The ITM therefore is believed to open new sights in epidermal electronics and skin prosthesis fields.

16.
Sci Adv ; 8(21): eabo5201, 2022 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-35622923

RESUMEN

Artificial haptic sensors form the basis of touch-based human-interfaced applications. However, they are unable to respond to remote events before physical contact. Some elasmobranch fishes, such as seawater sharks, use electroreception somatosensory system for remote environmental perception. Inspired by this ability, we design a soft artificial electroreceptor for sensing approaching targets. The electroreceptor, enabled by an elastomeric electret, is capable of encoding environmental precontact information into a series of voltage pulses functioning as unique precontact human interfaces. Electroceptor applications are demonstrated in a prewarning system, robotic control, game operation, and three-dimensional object recognition. These capabilities in perceiving proximal precontact events can lenrich the functionalities and applications of human-interfaced electronics.

17.
Front Behav Neurosci ; 16: 902175, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35832295

RESUMEN

Classical notion claims that a memory is implicit if has nothing to do with consciousness during the information retrieval from storage, or is otherwise explicit. Here, we demonstrate event-related potential evidence for involuntary consciousness during implicit memory retrieval. We designed a passive oddball paradigm for retrieval of implicit memory in which an auditory stream of Shepard tones with musical pitch interval contrasts were delivered to the subjects. These contrasts evoked a mismatch negativity response, which is an event-related potential and a neural marker of implicit memory, in the subjects with long-term musical training, but not in the subjects without. Notably, this response was followed by a salient P3 component which implies involvement of involuntary consciousness in the implicit memory retrieval. Finally, source analysis of the P3 revealed moving dipoles from the frontal lobe to the insula, a brain region closely related to conscious attention. Our study presents a case of involvement of involuntary consciousness in the implicit memory retrieval and suggests a potential challenge to the classical definition of implicit memory.

18.
ACS Nano ; 15(4): 7513-7521, 2021 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-33856770

RESUMEN

Triboelectric nanogenerators (TENGs), which hold great promise for sustainably powering wearable electronics by harvesting distributed mechanical energy, are still severely limited by their unsatisfactory power density, small capacitance, and high internal impedance. Herein, a materials optimization strategy is proposed to achieve a high performance of TENGs and to lower the matching impedance simultaneously. A permittivity-tunable electret composite film, i.e., a thermoplastic polyurethane (TPU) matrix with polyethylene glycol (PEG) additives and polytetrafluoroethylene (PTFE) nanoparticle inclusions, is employed as the triboelectric layer. Through optimizing the dielectric constant of the composite, the injected charge density and internal capacitance of the TENG are significantly enhanced, thus synergistically boosting the output power and reducing the impedance of the TENG. The optimal output power reaches 16.8 mW at an external resistance of 200 kΩ, showing a 17.3 times enhancement in output power and a 90% decline in matching impedance. This work demonstrates a significant progress toward the materials optimization of a triboelectric generator for its practical commercialization.

19.
ACS Appl Mater Interfaces ; 13(39): 46794-46802, 2021 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-34546695

RESUMEN

Poor room-temperature ionic conductivities and narrow electrochemical stable windows severely hinder the application of conventional poly(ethylene oxide)-based (PEO-based) solid polymer electrolytes (SPEs) for high-energy-density lithium metal batteries (LMBs). Herein, we designed and synthesized a PEO-based self-healing solid polymer electrolyte (SHSPE) via dynamically cross-linked imine bonds for safe, flexible solid LMBs. The constructed dynamic networks endow this SPE with fascinating intrinsic self-healing ability and excellent mechanical properties (extensibility > 500% and stress >130 kPa). More importantly, this SHSPE exhibits ultrahigh ionic conductivity (7.48 × 10-4 S cm-1 at 25 °C) and wide ESW (5.0 V vs Li/Li+). As a result, Li||Li symmetrical cells with the SHSPE showed reliable stability in a >1200 h cycling test under room temperature. The assembled Li|SHSPE|LiFePO4 cell maintained a discharge capacity of 126.4 mAh g-1 after 300 cycles (0.1C, 27 °C). This work highlights a promising strategy for next-generation room-temperature solid-state LMBs.

20.
ACS Macro Lett ; 10(7): 844-850, 2021 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-35549191

RESUMEN

Dendritic molecules with a fanlike or conelike conformation are common molecular building blocks to construct supramolecular columnar or spherical phases. Although it is well-accepted that the preferred molecular conformation of dendritic molecules dictates their packing schemes, manipulation of this crucial parameter usually requires significant changes in molecular structures and tedious synthetic efforts. Herein, we report a simple yet highly efficient strategy to tune the molecular conformation of dendritic rodlike molecules by adjusting the length of alkyl side chains tethered to the rods. Strikingly, tiny chemical structure differences can largely change the "crowding" near the branching point to induce the "fanlike to conelike" conformational transitions and thus result in the formation of diverse supramolecular structures, including the columnar phase, double gyroid phase, and the unconventional Frank-Kasper σ and A15 phases. Our study provides a practical platform for further investigation of unconventional structure formation and phase transitions in soft matter.


Asunto(s)
Estructura Molecular , Conformación Molecular
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