Pei Yang,Huihui Liu,Shuang Wang,Linghui Meng,Yongping Bai,Jinmei He
Paraffin wax (PW) coatings are widely used in the military as the most effective way to reduce the sensitivity of energetic materials, but their inert nature is not conducive to energy release. In this work, paraffin-like fluorine-containing molecules (FPW) which are highly anticipated on a large scale were synthesized by combining crystalline units with fluorine units via a simple method. Core-shell Al@FPW was prepared for further characterization. FPW exhibits better lubrication and greater density (1.14 g/cm 3 vs. 0.81 g/cm 3 ) than PW, which can provide favorable guarantees for reduced friction sensitivity and increased energy density . The similar melting temperatures and crystallization enthalpies (168 J/g vs. 201 J/g) of FPW and PW are advantageous for mitigating the temperature sensitivity of nano-Al. Furthermore, the improved hydrophobicity of Al@FPW prevents further oxidation of the active metal, thereby enhancing the preservation of nano-Al. Moreover, the reaction process of Al@FPW was characterized by DSC-Tg. Notably, the combustion pressure, pressurization rate and calorific value of Al@FPW are significantly increased compared to Al@PW. Meanwhile, the ignition delay time is reduced by 83 % and the combustion rate is increased by 330 %, which is attributed to the action of fluorine during the reaction. The exceptional performance of FPW holds great potential for replacing PW in various applications.
Yanting Du,Jiayu Li,Songhao Zhao,Haifeng Yu,Lei Ji,Shuhong Wang,Cheng Wang
Fluorinated materials have been widely utilized in optoelectronic devices. However, there has been a rare exploration of the use of fluorinated materials in polymer-based memory devices. To explore the impact of fluorinated acceptors on the storage capabilities of polymers, six donor–acceptor (D–A type) conjugated polymers were synthesized by using the Suzuki coupling reaction. Subsequently, polymers were utilized in the fabrication of basic sandwich-structured devices consisting of layers of indium–tin–oxide/polymer/aluminum (ITO/polymer/Al). Fluorinated polymers demonstrated significantly higher current switching ratios compared to non-fluorinated polymers. This increased ratio suggested an improved resolution in the readout, thus decreasing the probability of misinterpretation. It is imperative to emphasize that the poly[2-(2,3-bis(4-fluorophenyl)quinoxaline-5-yl)-9-(heptadecane-9-yl)-9H-carbazole] (PCzFQ) device exhibited exceptional performance, with an OFF:ON1:ON2 ratio as high as 1:101.8:104.7. This work supported the feasibility of introducing fluorine atoms into the acceptor unit to enhance the properties of memory devices, providing an available approach for synthesizing high-performance ternary memory materials.
Cai Lu,Lv Cun,Yan Xinyue,Mao Haiyan,Zhou Tianchi,He Xuemei,Zhu Tianxue
Fluorinated compounds with side-chains longer than six carbon have been banned due to their toxicity to environment, organisms and human, so that attentions have been paid on degradable short-chain fluorinated or non-fluorinated materials. Here in this paper, several novel short-chain fluorinated polysiloxanes with multi-functions were synthesized successfully and applied on cotton fabrics. Chemical structure of these fluorinated polysiloxanes were characterized by Fourier-transform infrared spectrum and nuclear magnetic resonance. Liquid repellency, washing durability, thermal stability, fabric style and color deepening of treated cotton fabrics were investigated. Additionally, the effect of benzoyl spacer on the surface wettability was fully studied. Results demonstrate that FPAPS-20@cotton (cotton fabric treated by fluorinated polysiloxane with 20% fluorine content) exhibits the greatest liquid repellency as the contact angles for water, ethylene glycol, glycerol and octane are 150.1°, 132.3°, 138.1° and 105.5°. Moreover, the benzoyl spacer plays a positive role in the durable wettability of FPAPS-20@cotton, resulting in the water contact angles ranging from 150.1° to 146.0° when FPAPS-20@cotton exposes to the water droplet for 20 min. X-ray photoelectron spectroscopy provides the experimental evidence for this result. On the other hand, thermal-gravimetric analysis confirms that the fluoroalkyl segments of the fluorinated polysiloxanes can decelerate the thermal decomposition of cotton fabrics. Moreover, compared with the untreated dyed cotton fabric, the K/S values of cotton fabrics with navy, red and orange color treated with FPAPS-20 increase by 42.61%, 11.00% and 18.18%, respectively.
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