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Sugar is a natural food and a common organic compound that widely exists in nature. Sugar features easy patterning, solubility in water, environmental friendliness, low cost, and easy combination with micro-nano process. In this study, sugar is proposed to be used as a micro-nano mask material in micro-nano fabrication. Results show that sugar can be easily used to fabricate various kinds of micro-nano mask patterns on different wettability substrates. The fabrication method based on sugar mask has many advantages; it is diverse, simple, pollution-free, and inexpensive. Besides, sugar is strongly compatible with micro-nano fabrication technology, because it can maintain good peeling properties, good viscosity, and good stability in subsequent micro-nano fabrication and achieve the high-quality transfer of mask patterns. In addition, graphite super-lubricity micro-nano movable devices are made through the proposed sugar mask method, which also has good and reliable performance compared with e-beam lithography. Compared with micro-nano fabrication based on photoresist masks, micro-nano fabrication based on the sugar mask is simpler and cheaper. In the micro-nano processing of the sugar mask, the lift-off and removal of residual sugar can be easily completed using water. In summary, we believe that sugar as a mask material is effective and can be widely used in micro-nano manufacturing.

In this paper, the focus of the study is the bio-signal monitoring sensor based on microbending effects and bending loss in fiber, the physical natures of the microbending effects and bending loss of multimode fiber are expounded through the microbending principle of fiber, and the effect of displacement on the microbending loss of fiber is explored and analyzed by deriving the microbending loss formula under the optical fiber theory. After putting the sensor on the back of a chair and letting the subject sit on the chair with the back on the sensor, the degree of microbend or radius of the fiber change as the change in chest volume during breathing results in the change in the external force, i.e., the force applied to the sensing part of the fiber. The physical change in the fiber induce changes in the amount of light energy transmitted in the fiber, causing optical loss. The respiratory rate is obtained by measuring the optical loss. The results show that the waveform displayed on the computer has good traceability performance, on which the frequencies of respiratory signals including normal breath, deep breath, and rapid breath can be distinguished. Experiments show that the sensor has good traceability feature and can automatically recognize the breathing conditions, with a signal-to-noise ratio of over 28dB

The demand for waterproofing of polymer (parylene) coating encapsulation has increased in a wide variety of applications, especially in the waterproof protection of electronic devices. However, parylene coatings often produce pinholes and cracks, which will reduce the waterproof effect as a protective barrier. This characteristic has a more significant influence on sensors and actuators with movable parts. Thus, a defect filling method of micro-nano composite structure is proposed to improve the waterproof ability of parylene coatings. The defect filling method is composed of a nano layer of Al2O3 molecules and a micro layer of parylene polymer. Based on the diffusion mechanism of water molecules in the polymer membrane, defects on the surface of polymer encapsulation will be filled and decomposed into smaller areas by Al2O3 nanoparticles to delay or hinder the penetration of water molecules. Accordingly, the dense Al2O3 nanoparticles are utilized to fill and repair the surface of the organic polymer by low-rate atomic layer deposition. This paper takes the pressure sensor as an example to carry out the corresponding research. Experimental results show that the proposed method is very effective and the encapsulated sensors work properly in a saline solution after a period of time equivalent to 153.9 days in body temperature, maintaining their accuracy and precision of 2 mmHg. Moreover, the sensors could improve accuracy by about 43% after the proposed encapsulation. Therefore, the water molecule anti-permeability encapsulation would have broad application prospects in micro/nano-device protection.

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