Porous polymers are gaining increased interest in several areas due, in great part, to their large surface area and unique physiochemical properties. Porous polymers are conventionally manufactured using specific processes related to the chemical structure of each polymer. With the wide variety of porous polymers that have been designed, fabricated, and tested to date, this review aims to provide an overview of the advances and recent progress in the preparation processes and fabrication techniques. A detailed comparison between these techniques is also provided. Some of these techniques offer the advantage of controlling the porosity and the possibility to obtain porous 3D polymers. A new generic fabrication process that can be applied to all liquid polymers to texture their outer surfaces with a desired porosity is also presented. The proposed process, which is based on two micromolding steps, offers flexibility in terms of tailoring the texture of the final polymer by simply using porous silicon templates with different pore sizes and configurations. The anticipated process was successfully implemented to texture polyethyl hydrosiloxane (PMHS) using porous silicon and polymethyl methacrylate (PMMA) scaffolds.
We propose a novel integrated micro-opto-mechanical-system spectrometer design in a monochromator setup. It consists of a concave grating fabricated in a planar waveguide that is connected to a rotational electrostatic actuator, which enables angular tuning of the grating. The spectrometer covers a wide operational wavelength range (>100 nm), covering partially the E-band and fully covering the S, C, and L-bands (1416.6 nm - 1696.6 nm), and requires a single photodetector to acquire the spectrum. The spectrometer is designed to exhibit low optical losses throughout the range of motion. The spectrum can be acquired at a frequency of 1.76 kHz. The simulated acquired spectrum features an average insertion loss of −1.8 dB and a crosstalk better than −70 dB with a resolution as low as 1.62 nm. The entire device covers an area of 4 mm x 4 mm and is based on a thick silicon-on-insulator platform.
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