JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Qi Wang,Chenlu Zhang,Hong Wu,Qiaoyuan Gao,Ran Duan,Chuncheng Chen
Bi 2 O 2 CO 3 was co-decorated by β-phase AgI and Bi 2 O 3 forming visible-light-active AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 composite via simply calcining AgI/Bi 2 O 2 CO 3 . The calcination temperature and time played vital role in regulating the structure as well as photocatalytic performance. Optimal AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 was obtained after 325 ◦ C calcination for 2 h with 5% AgI. The ratio of Bi 2 O 3 to Bi 2 O 2 CO 3 was estimated to be ca. 3:1 on the catalyst surface. The transformation process for n -type Bi 2 O 2 CO 3 to p-type Bi 2 O 3 (β) was monitored and verified by flat band potential measurements. Due to the presence of p-n junctions between p-type Bi 2 O 3 (β), n -type AgI(β) and Bi 2 O 2 CO 3 , the optimized ternary composite displayed enhanced photocurrent density and reduced charge transfer resistance, which were beneficial for photocatalytic applications. Despite of decreased specific surface area, dramatically enhanced photocatalytic performance can be observed for simultaneous removal of Cr(VI) and phenol . For example, the estimated k Cr(VI) and k phenol on AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 were 3.3 and 2.2 times relative to those on uncalcined AgI/Bi 2 O 2 CO 3 , respectively. The optimized composite also displayed good stability in 4 successive cyclic runs.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Qilai Zhou,Yasuhisa Oya,Takumi Chikada,Wen Zhang,Lihong Xue,Youwei Yan
Ultrafine lithium titanate (Li 2 TiO 3 ) powder was synthesized by hydrothermal method . The phase formation and transition condition among α, β, and γ-Li 2 TiO 3 were discussed. XRD and ICP-AES showed the single α-phase was formed at 180 °C with 2 h hydrothermal reaction, and it transited into β-phase at 400 °C. SEM observation and EDS analysis confirmed the dissolution of TiO 2 and the formation of α-Li 2 TiO 3 proceeded simultaneously with preferable growth direction of (-133) lattice. During the phase transition, the powder maintained the small crystallite , which facilitated the fabrication of Li 2 TiO 3 bulk with small grain size. After the Ar + irradiation, the surface region to the depth of 3 μm of Li 2 TiO 3 ceramic was affected, where the decrease of crystallization and disturbance of short-range order were confirmed by GIXRD and Raman spectroscopy . In spite of the structure change at the surface area, the ceramic bulk maintained the same.
研究领域:
材料科学
·
核能工程
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产品关联
DOI
高影响因子
Micromachines
·
2021
·Vol. 12
·期 6
·602
·
IF 2.891
Mingran Liu,Yang Liu,Limin Zhou
With the development of human healthcare devices, smart sensors, e-skins, and pressure sensors with outstanding sensitivity, flexibility, durability and biocompatibility have attracted more and more attention. In this paper, to develop a novel flexible pressure sensor with high sensitivity, different poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)-based composite membranes were fabricated, characterized and tested. To improve the β-phase crystallinity and piezoelectricity of the membranes, and for the purpose of comparison, nano ZnO particles with different concentrations (99:1, 9:1 in a weight ratio of PVDF-TrFE to ZnO) were, respectively added into PVDF-TrFE polymer acting as a nucleating agent and dielectric material. To facilitate the formation of β-phase crystal, the membranes were fabricated by electrospinning method. After the electrospinning, an annealing process was conducted to the fabricated membranes to increase the size and content of β-phase crystal. Then, the fabricated PVDF-TrFE membranes, acting as the core sensing layer, were, respectively built into multiple prototype sensors in a sandwich structure. The sensitivity of the prototype sensors was tested by an auto-clicker. The stimulation of the auto-clicker on the prototype sensors generated electrical signals, and the electrical signals were collected by a self-built testing platform powered by LabVIEW. As a result, combining the addition of ZnO nanofillers and the annealing process, a highly sensitive pressure sensor was fabricated. The optimal peak-to-peak voltage response generated from the prototype sensor was 1.788 V which shows a 75% increase compared to that of the pristine PVDF-TrFE sensor. Furthermore, a human pulse waveform was captured by a prototype sensor which exhibits tremendous prospects for application in healthcare devices.Keywords:PVDF-TrFE;PVDF-TrFE/ZnO;β phase crystal;human pulsation sensor
研究领域:
材料科学
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yue Shen,Zheng Li,Ying Liu,Jing Tao Wang
Polyvinylidene fluoride (PVDF) has attracted significant attention for its unique piezoelectric and ferroelectric properties. However, traditional processing primarily results in the non-polar α phase, limiting its applications. This study prepared PVDF films via solution casting followed by rolling at various temperatures to promote the transition to the β phase. High-temperature rolling significantly enhanced the β phase content, improved the microstructure and orientation of the films, and markedly enhanced the piezoelectric and ferroelectric properties. Particularly, the films rolled at 90 °C exhibited a higher relative content of the β phase, showing exceptional piezoelectric performance with a d 33 value of 26 pC/N and ferroelectric properties with a remanent polarization (P r ) of 13.69 μC/cm 2 . Additionally, hot rolling at higher temperatures notably improved the mechanical properties, enhancing both tensile strength and elongation at break. The optimized PVDF films present broad application prospects in areas such as sensors. This study provides a method and theoretical guidance for the preparation of high-performance PVDF-based functional materials.
研究领域:
材料科学
·
传感器技术
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产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Jianfei Xia,Lingling Ni,Chang Zeng,Bao Wang,Rui Zhang,Chenxuan Sun,Jian Song,Junfeng Liu,Chengtao Yu,Ying Zheng,Pengju Pan
Terephthalic polyesters are important engineering plastics and can crystallize into multiple crystal phases, including the mesophase in processing. However, the formation process and structural characteristics for the unique long-range ordered mesophase of terephthalic polyesters are still not well understood. Herein, we investigated the crystal polymorphism, crystallization kinetics, phase transition, and mechanical properties of a medium-chain terephthalic polyester, poly(hexamethylene terephthalate) (PHT). A new long-range ordered mesophase (named as the δ phase) is discovered for PHT during quiescent melt crystallization at a low crystallization temperature (Tc = 10–30 °C). However, the α and β crystal phases are crystallized at a medium (40–80 °C) and high (90–130 °C) Tc, respectively. The mesomorphic δ phase has a long-range order with a layered structure and inclined chain packing, which shows faster chain relaxation and smaller lamellar thickness than the α and β phases. The mesomorphic δ phase is metastable and converts into the stable β phase upon heating or high-temperature annealing. Mechanical properties of PHT can be well tuned by crystal polymorphs. The mesomorphic δ phase of PHT has good transparency and ductility, while the α and β phases possess a higher yield strength and modulus. This work provides an in-depth understanding of the mesophase formation and complex crystal polymorphism of terephthalic polyesters.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2023
·Vol. 54
·期 2
·712-733
·
IF 3
Zhang Xi,Na Hao,Liu Pengyao,Wang Yajun,Li Junguo,Meng Qian,Li Guopeng
Regulating the phase transformation of γ → β in dicalcium silicate (C 2 S) can effectively improve the hydration activity and recycling rate of AOD slag; however, the evolution law for γ → β in C 2 S has not been extensively investigated. In this study, a novel “two-step” γ → α ′ L → β phase transformation method in C 2 S was designed based on the study of the pure C 2 S phase at a nonequilibrium state in the low- and middle-temperature ranges. The “two-step” method can be used to realize the transformation from needle-like nanostructured γ -C 2 S grains to lamellar-structured β -C 2 S grains, exhibiting the trend of interlaminar peeling accompanied by expansion of the particle volume and leading to the appearance of macroscopic lamellar cracking in β -C 2 S particles. In addition, the β -C 2 S mass fraction in AOD slag treated by water cooling at 680 °C reaches a maximum value of 47.5 wt pct, while the treated AOD slag presents abundant holes and defects, which can effectively enlarge the hydration contact area.
研究领域:
材料科学
·
无机化学
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产品关联
DOI
高影响因子
Nano Energy
·
2020
·
IF 16.602
Shengrui Yu,Yongkang Zhang,Zhaohan Yu,Jiaqi Zheng,Yunming Wang,Huamin Zhou
Limited by the inherent properties of being difficult to be polarized due to its high resistance, PVDF bulk material with high β-phase content is hard to obtain by conventional methods which are suitable for membrane material. Herein, a novel strategy is proposed for the mass production of high-performance β-PVDF-based piezoelectric and triboelectric hybrid nanogenerator (PTNG) employing large-scale PVDF films or bulks by using liquid nitrogen to induce a phase transition and in-situ doped conductive polyaniline (PANI). Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) with high piezoelectric coefficient , filled with PANI as a conductive material and sodium carboxymethyl cellulose (SCMC) for increasing porosity, is hot pressed to obtain a composite piezoelectric polymer for PTNG. The subsequent “quenching” process of the piezoelectric polymer allows its high content of β-phase, which in turn makes the PTNG exhibit excellent piezoelectric properties . The optimal output of the PTNG, with a β-phase content of up to 71%, reaches 246 V and 122 μA at the frequency of 30 Hz and pressure of 0.31 MPa, and the power density is calculated to be 6.69 W/m 2 . Moreover, the PTNG can directly light up 119 blue light-emitting diodes (LEDs) with a size of 3 mm in series. The excellent performance verifies the reliability and accuracy of the method, that is, the β-phase transformation of disordered amorphous PVDF occurs at low temperature and high-rate quenching, and PANI opens the channel for carriers to move charge in the bulk material. This innovative method presented here is a simple and efficient approach for preparation of bulks with high β-phase and low internal resistance, which undoubtedly provides a feasible direction for the industrialization of high-performance PENGs.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS A-PHYSICAL
·
2025
·
IF 4.9
Zhaohua Liu,Yi Xue,Jian Yang,Weihuan Lin,Ivan S. Babichuk
The coexistence of increasingly severe environmental issues and bio-signal sensing systems necessitates comfortable and safe wearable devices for continuous human health monitoring. Bio-based piezoelectric materials that are environmentally friendly, biocompatible, and high-performing show great potential in health monitoring and human-computer interaction. Chitosan, a deacetylated product of chitin, is one of the natural piezoelectric biopolymer materials. Due to its complete degradability, excellent film-forming properties, and renewability, it has garnered significant attention in the field of piezoelectric sensing. Here, we explored the impact of different degrees of deacetylation on the crystal structure of chitosan and found that chitosan with a deacetylation degree of 70 % (CS−70) has the highest content of the β −phase. On this basis, 2,3-epoxypropyl trimethyl ammonium chloride (GTMAC) was grafted onto the amino groups of chitosan to induce the formation of the β −phase. It was proven that the proportion of the β −phase increased from 41.16 % to 56.46 %. By employing a simple processing method, we manufactured the quaternary ammonium chitosan film flexible pressure sensors. When the material ratio was 1:1, it produced the highest piezoelectric output of 0.325 V, with a sensitivity of 25.64 ± 1.22 (mV/kPa), which is 1.67 times and 2.3 times higher that of the original chitosan, respectively, and also possesses a high linearity characteristic (adjusted R 2 =0.99). Moreover, the flexible piezoelectric sensors were successfully applied to human motion detection, physiological signal detection, and human-computer interaction. Considering their scalability and ease of manufacturing, this study provides a new reference for the development of green, flexible, and high-performance electronic devices.
研究领域:
材料科学
·
生物医学工程
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Jun Yu,Tiantian Yue,Mengqi Wang,Yi Liu,Fan Liao,Zhenhui Kang,Yuqing Liu
Flexible piezoelectrics are pivotal for self-powered wearable systems, yet low-dimensional materials like PVDF fibers suffer from inefficient β-phase crystallization and limited charge transport. Here, coaxial wet-spun polyvinylidene fluoride (PVDF) fibers integrated with carbon quantum dots (CDs) overcome these limitations via solvent-nonsolvent phase separation and mechanical stretching. A 3 wt% CDs doping induces 75.96 % β-phase content through interfacial hydrogen bonding, achieving a high piezoelectric coefficient (d 33 of 28 pC/N) and output performance of 19.4 V and 0.2 μA, which is 86.7 % surpassing pristine PVDF(15 pC/N), and Under optimal experimental conditions, the peak voltage and current can reach up to 31 V and 0.2 μA. Cyclic durability tests (3 Hz, 20 N, 1000 cycles) confirm excellent stability with > 90 % performance retention. Practical applications highlight rapid capacitor charging (5 V in 30 s) and the ability to power nine LEDs. Additionally, bending sensitivity (3.6 V at 60°) and motion sensing (9 V for arm bending) validate its adaptability for wearable electronics and IoT applications, offering a scalable strategy for high-performance flexible energy harvesters.
研究领域:
材料科学
·
能源技术
·
纳米科技
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Haodong Huang,Ziqi Wang,Zhen Zhang,Chongyang Wang,Yanping Liu,Chuntai Liu,Chunguang Shao,Zhen Wang
Exploring milder high-pressure processing conditions is essential for developing heat-resistant electroactive poly(vinylidene fluoride) (PVDF) materials based on polar extended-chain crystals (ECCs). Herein, we introduced a typical imidazole ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate, to manipulate the melt crystallization of PVDF under high pressure. Our findings reveal a dual role of IL in ECCs formation through various structural and morphological characterizations. First, it increases the free energy of growing nuclei by raising the end surface free energy σe, making ECCs formation thermodynamically unfavorable. Second, it facilitates chain sliding diffusion and lowers the diffusion activation energy during nuclei growth, which promotes ECCs generation in kinetics. These two effects compete with each other, influenced by crystallization conditions and IL content. Kinetic promotion prevails at low crystallization temperatures (Tp) and low IL fractions, while thermodynamic inhibition dominates at high Tp and/or high IL fractions. This interplay is illustrated by high-pressure phase diagrams of PVDF/IL blends. A low IL fraction (e.g., 0.2%) significantly expands the ECCs growth region into lower Tp and pressure conditions, while a higher IL fraction has the opposite effect. This knowledge enables the rapid preparation of abundant ECCs with minimal IL addition at milder low temperatures, thereby minimizing sample degradation. Furthermore, the IL-induced ECCs primarily consist of the polar β-phase and maintain a high melting point. This study elucidates the high-pressure crystallization mechanism of PVDF/IL blends and proposes an effective strategy for enhancing the production of polar ECCs in PVDF homopolymer.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
AIP Advances
·
2019
·Vol. 9
·期 11
·
IF 1.579
Zhang Jianwen,Cao Peng,Cui Zhaoliang,Wang Qian,Fan Fan,Qiu Minghui,Wang Xiaozu,Wang Zhaohui,Wang Yong
Membrane fouling can be efficiently mitigated by the vibration of the piezoelectric membrane stimulated by AC signals, but it is still a challenge to fabricate piezoelectric membranes with great efficiency, low energy-consumption, and no harm to the environment during its preparation. The present work provides a new approach to poly(vinylidene fluoride) (PVDF) membranes with piezoelectric properties by directly poling β-phase PVDF membranes using green diluents, which revealed better piezoelectric properties than poling α-phase PVDF membranes. Basically, absolute β-phase crystals of PVDF membranes were induced over thermally induced phase separation with the addition of Acetyl tributyl citrate (ATBC)/ionic liquid ([BMIM]PF 6 ), which are regarded as green and environment-friendly diluents. To endow the piezoelectric property to the β-phase PVDF membrane, a poling process was necessarily conducted. The effect of the poling process on the membrane structure, morphologies, properties, and performances was investigated. Meanwhile, a vibration test for both of the poled and unpoled membranes was performed in an excitation of the alternating signal. The results demonstrated that the poling process positively endowed the piezoelectric property to the PVDF membranes. The membrane structure, morphologies, and performances of the membranes were also changed to some extent by the poling process. Additionally, filtrations of the poled membrane both with and without electrical signals were carried out to test their antifouling performance on the CaCO 3 suspension system and BSA solution, respectively. It was observed that the stable flux of the membranes notably improved when subjected to an electrical AC signal. Thus, it depicted that the piezoelectric PVDF membrane directly poled from the β-phase possesses a promising antifouling performance due to its high piezoelectric vibration.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2019
·Vol. 30
·期 5
·1497-1502
·
IF 1.637
Wang Andong,Chen Caifeng,Liao Linchen,Qian Jilong,Yuan Fuh-Gwo,Zhang Ningyi
This research work reports on development and characterization of polyvinylidene fluoride (PVDF) thin films by intercalation of graphene during direct ink writing process with auxiliary electric potential (voltage). The effects of graphene additive on the crystallinity and β-phase transformation in PVDF thin films are studied. The results show that small amount of graphene additive in the writing ink promotes the crystalline nucleation, and the micro electric fields among graphene sheets also promote the formation of the folded β-PVDF chains and prevent the spherulite growth. When 0.05 wt% amount of graphene was added in the writing ink, the crystallinity of the thin film was about twice higher than that of the pure PVDF thin film, and the β-phase content in the thin film reached 67.30%. The sensitivity of the PVDF/graphene composite film is also much higher than that of the pure PVDF piezoelectric film.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）