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Microfluidic devices typically require complex shapes such as funnels, spirals, splitters, channels with different widths, or customized objects of arbitrary complexity with a smooth transition between these elements. Device layouts are generally designed by software developed for the design of integrated circuits or by general computer-aided design drawing tools. Both methods have their limitations, making these tasks time consuming. Here, a script-based, time-effective method to generate the layout of various microfluidic chips with complex geometries is presented. The present work uses the nanolithography toolbox (NT), a platform-independent software package, which employs parameterized fundamental blocks (cells) to create microscale and nanoscale structures. In order to demonstrate the functionality and efficiency of the NT, a few classical microfluidic devices were designed using the NT and then fabricated in glass/silicon using standard microfabrication techniques and in poly(dimethylsiloxane) using soft lithography as well as more complex techniques used for flow-through calorimetry. In addition, the functionality of a few of the fabricated devices was tested. The powerful method proposed allows the creation of microfluidic devices with complex layouts in an easy way, simplifying the design process and improving design efficiency. Thus, it holds great potential for broad applications in microfluidic device design.

The modification of surface properties frequently requires the binding of suitable compounds to the original surface. Silanes or thiols can be directly covalently bonded to either Si-based materials or Au, thus ruling out polymers. Here, we show the utilization of a layer of SiO2 with a thickness of a few nanometers that serves as a cross-linker between polymers and silanes providing covalent bonding to the surface. We deposited a polymer onto a thermally oxidized microstructured Si surface followed by subsequent Si removal. We demonstrated a Si-based nanotechnology fabrication method that can be generally used to modify the surface properties of practically any polymer via SiO2 cross-linking. This can produce any topology, including microstructures, nanostructures, or composite microstructure/nanostructures terminating in different shapes, since all the steps involving polymer deposition are conducted at room temperature after the Si surface has been thermally oxidized. This technique opens a broad field of new applications for polymers in microstructures and nanostructures that have stable water surface contact angle values with the contact angle set by demand for gecko-mimicking structures or lotus leaf inspired surfaces.