聚二甲基硅氧烷(PDMS)

Abstract(#br)Supercritical carbon dioxide (scCO 2 ) is used in the food industry as a water-extracting drying agent. Once saturated with water, the scCO 2 needs to be regenerated. A promising way of drying scCO 2 is by using H 2 O permeable membranes. Ideally, these membranes demonstrate low CO 2 permeability. Here, we investigated the CO 2 permeability of three types of dense membranes, Nafion, Natural Rubber and PDMS, of which the latter in more detail because of its ease of handling.

文摘( # br )在超临界二氧化碳( scCO2 )条件下通过致密的聚二甲基硅氧烷( PDMS )进行水蒸气渗透，压力高达185bar，以评价scCO2作为干燥剂对常规干燥过程中易发生产品劣化的新鲜产品脱水的再生能力。本研究实验考察了在亚超临界CO2存在下，浓差极化对H2 O蒸汽透过致密PDMS膜的影响。将结果与含N2而不含CO2的体系进行了比较。( # br )对于CO2体系，在90bar时，随着进料压力的增加，不考虑膜层阻力的残馀传质阻力下降为零。这是进料本体和渗透液H2 O含量趋同的结果，导致进料边界层内主要H2 O输运机制由扩散转变为对流。这里H2 O和CO2分子以可比的速度向膜表面输送。对于含N2的体系，由于即使在高压下，H2 O和N2之间的传输速度仍保持着明显的差异，因此出现了相反的趋势。因此，通过PDMS膜的水汽输送速率受基质流体类型( CO2或N2 )的控制。

摘要( # br ) PDMS作为一种广泛应用于细胞力学研究的弹性体，在细胞培养制备过程中受到多种表面处理。特别是考虑到其粘弹性性质，上述处理对PDMS力学行为的影响，尤其是在相关长度尺度为100 μ m时，受到的关注有限。尽管由于PDMS力学性能的微小变化，在定量细胞牵引力方面报告了重大误差。因此，本文通过拉伸和应力松弛实验，研究了等离子体氧化、灭菌和孵育对PDMS弹性模量、松弛模量和泊松比的影响，并通过线性黏弹性方程解释了后者的结果。观察到，虽然通过这一循环的表面处理测量了与未处理PDMS性能的显著偏差，但未经处理的PDMS在细胞培养基中孵育后性能几乎恢复。例如，处理后的PDMS的弹性模量比未处理的PDMS小6 %，对应的松弛模量和时均泊松比偏差分别\u003c 3 %和\u003c 1 %。在细胞培养基中培养过程结束时，泊松比随时间的变化率也被发现降低。因此，未处理PDMS的黏弹性性能可以在本工作提供的误差范围内安全使用。

This article describes the design and the functional verification of fiber optic system with an innovative non-invasive measuring probe for monitoring respiratory and heart rate. The measuring probe is based on Fiber Bragg Grating (FBG), and it is encapsulated in the PolyDiMethylSiloxane polymer (PDMS). PDMS offers a unique combination of suitable properties for the use in biomedical applications. The main advantages include inert to human skin and immunity to electromagnetic interference. The measuring probe is a part of contact strip which is placed on the chest of the patient.

Liver organoids hold a great potential to understand liver development and contribute for drug screening and toxicological testing. However, conventional methods to generate organoids provide insufficient liver functions and less reproducibility, due to lack of controllability of cellular microenvironmental cues. To tackle these issues, we focus on one of the environmental cues, pressure stimuli by heart beating, and develop a microfluidic-based cell culture platform integrating a fluidic capacitor to produce pressure stimuli with hydrostatic pressure.

Nonspherical monodisperse polydimethylsiloxane (PDMS) microparticles were fabricated by lithography and ultraviolet ozone (UVO) treatment for self-assembly of periodic structures. PDMS solution was poured into photoresist molds on glass substrates, whereupon it was cured at 80°C. After irradiating ultraviolet to the surface of the PDMS, remaining thin PDMS films on the molds were eliminated using ultrasonic waves.

Photocatalytic TiO\u003csub\u003e2\u003c/sub\u003e layers prepared by PVD or CVD processes are already produced industrially. The deposited TiO\u003csub\u003e2\u003c/sub\u003e needs a sufficiently high concentration of the photocatalytically active anatase phase which is produced at higher substrate temperature. As a consequence, the PVD/CVD techniques are limited to heat‐resistant substrates.

Synthesis and Characteristic of Polyurethane Modified Siliconepolyurethane modified silicone (PUMS);polydimethylsiloxane (PDMS);polypropyleneglycol (PPG);2,4-toluenediisocyanate (TDI);Polyurethane modified silicone (PUMS) was synthesized from various molecular weights of polydimethylsiloxane (PDMS 2000, PDMS 6000, PDMS 20000), polypropyleneglycol with molecular weight of 3000 g/mol (PPG 3000) and 2,4-toluenediisocyanate (TDI) under tin catalyst. Their structures were confirmed by the measurement of FT-IR and $^1H-NMR$, and the thermal properties were studied from DSC and TGA.

Polydimethylsiloxane (PDMS) is an important polymer with numerous applications. Herein, the authors report the optical function(s) of PDMS from 191 to 1688 nm as determined from reflection spectroscopic ellipsometry (SE) and transmission ultraviolet-visible data. Two commercial samples of liquid PDMS (PDMS700 and PDMS2000) with molecular weights of 700–1500 g/mol and 2000–3500 g/mol, respectively, were analyzed. Both samples were linear polymers terminated with silanol groups. The optical functions determined from the two materials were essentially identical.

多生理信号的同时测量可为疾病提供有效的诊断和治疗评估。本文报道了一种基于碳纳米管( CNT ) -聚二甲基硅氧烷( PDMS )的可穿戴设备，具有压阻和电压传感功能，可同时捕获腕脉压和心脏电信号。通过分析应变分布和电场分布来指导装置中传感元件的布置设计，以减小测量过程中腕脉与心脏电活动之间的干扰。每个装置在20 %的应变下进行预处理，直到装置的电阻变化达到平衡。预处理后，标定了电阻变化与压力的关系，确定了装置的灵敏度为0.01   Pa-1，线性压力范围为0.4 ~ 14.0   kPa。通过扫描电子显微镜( SEM )成像和等效电路模型研究了CNT- PDMS对应变信号和电脉冲信号的传感机理。该装置用于监测志愿者在运动后恢复过程中的腕脉搏和心电信号。