With the growth of silicon-based semiconductor sensors in the global sensor market, advancements in body motion detection for wearable devices and sustainable health monitoring have accelerated. This has led to a significant attention on various sensors with excellent flexibility and stretchability, such as PDMS, in numerous applications. In this study to adjust the sensitivity of conventional conductive pressure sensors, a porous sponge structure was initially created using a sugar template method. The polymer was prepared with four different ratios (5:1, 10:1, 20:1, 30:1) to achieve varying flexibilities. To ensure conductivity, the sponge was coated using a dip-coating method with a 3wt% CNT solution. The conductive sponges with various ratios were tested for sensitivity, demonstrating characteristics suitable for a wide range of pressure sensing applications.

Sensors for monitoring human body movements have gained much attention in the recent times especially in the health-care sector as these devices offer real-time monitoring of vital physiological signs, enabling health-care professionals to evaluate health conditions and provide remote feedback. In this work, we have fabricated carbon-nanotube (CNT)/ polydimethylsiloxane (PDMS) composite sensor through simple dispersion and freezing method for monitoring flexion movements in humans. Sensors with different CNT loadings, namely 0.1 wt %, 0.5 wt %, and 1 wt % were fabricated and analyzed to find the best performing sensor. Several characterizations like Raman, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), tensile strength measurements, and piezoresistive studies were carried out to study the features of the sensors. Among the fabricated sensors, the one with the loading concentration of 0.5 wt% is found to be most sensitive for flexion applications with higher gauge factor of 533 at 60% strain level, response time of ~ 140 ms and lower hysteresis loss. The feasibility of the sensor for monitoring flexion like finger bending, wrist bending, elbow bending, and knee bending is also analyzed making it ideal for use in sports for athletes, physicians, and trainers to investigate physical performance and well-being.

The demand for energy is steadily rising because of rapid population growth and improvements in living standards. Consequently, extensive research is being conducted worldwide to enhance the energy supply. Transpiration power generation technology utilizes the vast availability of water, which encompasses more than 70% of the Earth's surface, offering the unique advantage of minimal temporal and spatial constraints over other forms of power generation. Various principles are involved in water-based energy harvesting. In this study, we focused on explaining the generation of energy through the streaming potential within the generator component. The generator was fabricated using sugar cubes, PDMS, carbon black, CTAB, and DI water. In addition, a straightforward and rapid manufacturing method for the generator was proposed. The PDMS generator developed in this study exhibits high performance with a voltage of 29.6 mV and a current of 8.29 μA and can generate power for over 40h. This study contributes to the future development of generators that can achieve high performance and long-term power generation.

알코올의 탈수를 위하여 에너지 다소비 공정인 증류 공정을 투과증발 막 공정으로 대체하려는 연구가 많이 진행 되어져 왔다. 대표적인 투과증발 막인 PDMS 분리막에 대한 시간의존적 분리 거동은 분리 메카니즘의 이해에 매우 중요하다. 따라서 본 연구에서는 50 wt% 에탄올-물 혼합용액에 대하여 50°C에서 막면적 1194 cm2인 PDMS/PSF 분리막 모듈의 시간의 존적인 투과증발 분리 거동을 고찰하였다. 총 유속과 에탄올/물 분리계수는 투과증발 시간이 증가함에 따라서 초기에 증가하 다가 다시 감소하였다. 초기 분리성능의 증가는 건조한 PDMS 분리막에 에탄올이 용해되는데 시간이 걸리기 때문이며, 후기 분리성능의 감소는 주입 탱크의 에탄올 농도가 시간에 따라서 감소하기 때문에 나타나는 현상이었다. 따라서 본 연구로부터 PDMS 분리막을 통한 에탄올의 투과는 용해-확산 메카니즘에 의해 발생된다는 것이 재확인되었다.

리튬금속전지(LMB)는 매우 큰 이론 용량을 갖지만 단락(short circuit), 수명 감소 등을 야기하는 덴드라이트(dendrite) 가 형성되는 큰 문제점을 갖고 있다. 본 연구에서는 poly(dimethylsiloxane) (PDMS)에 graphene oxide (GO) nanosheet를 고르게 분산시킨 PDMS/GO 복합체를 합성하였고 이를 박막 형태로 코팅하여 덴드라이트의 형성을 물리적으로 억제할 수 있는 막의 효과를 이끌어내었다. PDMS의 경우, 그 자체로는 이온 전도체가 아니기 때문에 리튬 이온의 통로를 형성시켜 리튬 이온의 이동을 원활하게 하기 위하여 5wt% 불산(HF)으로 에칭하여 PDMS/GO 박막이 이온전도성을 가질 수 있도록 하였다. 주사전자현미경(scanning electron microscopy, SEM)을 통해 전면 및 단면을 관찰하여 PDMS/GO 박막의 형상을 확인하였다. 그리고 PDMS/GO 박막을 리튬금속전지에 적용하여 실시한 배터리 테스트 결과, 100번째 사이클까지 쿨롱 효율(columbic efficiency) 이 평균 87.4%로 유지되었고, 박막이 코팅되지 않은 구리 전극보다 과전압이 감소되었음을 전압 구배(voltage profile) 를 통해 확인하였다.

High performance polydimethylsiloxane (PDMS) membranes for n-butanol recovery were fabricated using a tri-functional crosslinker containing the phenyl group. In order to understand the role of the functional group structure and cross-linking density in pervaporation performance, PDMS membranes were prepared using tri-functional crosslinker containing other functional groups (hexyl and cyclohexyl) and conventional tetra-functional crosslinker. The relationship between the polymer structure-performance was discussed based on the sorption and diffusion properties of the membranes. As a result, the phenyl-based PDMS membrane exhibited the pervaporation performance owing to the strong hydrophobicity and chain rigidity of the phenyl group compared to other PDMS membranes even at high butanol concentration and high temperature conditions.

본 연구에서는 각기 다른 두 제조사의 AgNW를 활용하여 스핀코팅 속도, 열처리 온도 및 방법 그리고 PDMS코팅 속도에 따른 AgNW/PDMS composite공정 연구를 실시하였다. 실험결과 peel off 특성에 영향을 미치는 인자로 건조방식이 주요하게 작용하며 공정온도 또한 전극 특성에 영향을 주었다. 핫플레이트를 사용한 건조방식은 한방향 열전달로 인해 PDMS를 충분히 건조시키지 못하였지만 오븐 건조를 통해 그 결점을 보완할 수 있었다. 또한, PDMS 코팅속도가 증가함에 따라 스트레처블 특성이 향상되었고 GF는 0.03에서 0.07로 약 100정도 향상되었다.

Carbon dioxide recovery by vacuum stripping at low temperatures (below 100°C) could be a promising technology to substitute the desorption process in conventional aqueous amine absorption process. We prepared composite membranes by coating hydrophobic silicalite-filled PDMS layers on porous PE supports and used as new membrane strippers for CO2 recovery to prevent typical pore wetting problem of hydrophobic PTFE porous membranes. CO2 fluxes were measured under various operation conditions, such as different vacuum pressures, stripping temperatures, CO2 loadings, types of amine solutions and operation time. The composite membranes showed excellent long-term stability in vacuum stripping process when compared with porous PTFE membranes.

Polyimides (PI) have the high mechanical, thermal, and chemical stability. However, they have low permeability resulting from rigid chain structure. On the other hand, PDMS is a highly CO2 permeable soft polymer. To overcome low permeability of polyimide, we developed PDMS-based polyimide block copolymer. The effect of PDMS contents on the gas separation properties will be discussed in detail.

Polyimides (PIs) are known to have the high mechanical and thermal stability, but they have limited application for gas separation due to their low permeability. To overcome the low permeability of PIs, we developed PDMS-containing PI copolymers with different PDMS compositions as highly permeable polymer membranes. The piperazinium group was further introduced on the side chains of the PDMS-PIs both as crosslinkers and CO2-solubilizing groups. The preparation and properties of the corresponding polymer membranes for CO2 separation will be discussed.