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Viscoelastic Functions: Effect of Various Parameters
Published in B. R. Gupta, Rheology Applied in Polymer Processing, 2023
It is vital to carefully select the polymer material for the fabrication purpose as well as for the chip. Some of the most used polymers for the purpose of fabricating the microfluidic devices are : Poly(dimethyl-siloxane) (PDMS). [149, 150, 151]; Poly(methylmethacrylate) (PMMA)[152, 153]; Polycarbonate (PC) [154, 155]; Polyester[156]; Polystyrene (PS)[157] and SU-8[158, 159, 160]. SU-8 is the material that can be easily strucured using standard lithography technique, with features ranging from a few to hundreds of micrometers[161, 162]. However it need to be noted that SU-8 has high optical losses in UV region and high water permeability. PDMS is probably the most popular polymer for soft lithography due to easy fabrication and bonding.
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Published in Luis Liz-Marzán, Colloidal Synthesis of Plasmonic Nanometals, 2020
Cyrille Hamon, Luis M. Liz-Marzánac
In this section we focus on methods used to create plasmonic structures from patterned substrates, rather than on the fabrication of the substrate itself. Among the various nanofabrication methods, soft lithography comprises a family of techniques that allow the replication of a predefined structure by using an inexpensive elastomeric material.[18] Polydimethyl siloxane (PDMS) is probably the most widely used synthetic material toward the manufacture of soft lithography templates. PDMS has a number of advantages such as low cost, flexibility, the ability to accurately reproduce tiny features with a high resolution, and simple transfer of assemblies onto another substrate of interest. Other polymeric materials are currently used to design templates, such as polymethyl methacrylate (PMMA), which present the advantage to be easily lifted off after the assembly is completed.[19]
Advances in the Processing and Fabrication of Bioinspired Materials and Implications by Way of Applications
Published in T. S. Srivatsan, T. S. Sudarshan, K. Manigandan, Manufacturing Techniques for Materials, 2018
Lakshminath Kundanati, Nicola M. Pugno
Soft lithography can be viewed as an extension of the standard photolithography technique and is primarily used for replica molding in case of micro- and nanofabrication procedures. In brief, a soft elastomeric stamp with patterned microstructures is used to make replicas of structures with a size range from nanometers to micrometers (Xia and Whitesides 1998). It is a low-cost, convenient, and effective method. However, fabricating fibers with a high aspect ratio such as cilia requires higher stability than that of a soft elastomer like polydimethylsiloxane (Grinthal et al. 2012). Using thermo-curable polymers, a novel method was developed that enables fabrication of 3D parts with complex geometries that are difficult to fabricate in conventional processes (Rodrigue et al. 2015).
Generating direct diamond shaping tool paths using special-purpose computer-aided-machining post-processor
Published in International Journal of Computer Integrated Manufacturing, 2022
Darren Wei Wen Low, Nicholas Yew Jin Tan, Dennis Neo Wee Keong, A. Senthil Kumar
Besides the development of optical components, DDS can also directly and reliably machine ultrafine channels for microfluidic applications. Currently, soft lithography is usually employed for the fabrication of high-mix low-volume microfluidic chips with fine channels. However, soft lithography is limited to PDMS as a base material. This limits the applications of such microfluidic chips due to its inferior material properties compared to other common lab materials like PMMA and glass (Regehr et al. 2009; Toepke and Beebe 2006). Also, due to the nature of the fabrication process, microchannels developed using soft lithography are also prone to collapsing due to incomplete curing. Other processes such as stereolithography and etching have also shown limitations in terms of material selectivity (Ho et al. 2015; Ziaie et al. 2004). Laser ablation on the other hand lacks flexibility in cross-sectional profiles, as well as poor surface finish and power-optimization issues (Mccann et al. 2016; Suriano et al. 2011). Micro-milling also faces difficulties in fabricating such small features, such as the presence of feed marks, minimum tool diameter and high wear rate due to increased contact time, diminishing the quality of the feature especially when optical surfaces are required (Guckenberger et al. 2015).
Enhenced cell adhesion on collagen I treated parylene-C microplates
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Lijun Zhao, Weiwei Lan, Xiao Dong, Han Xu, Lili Wang, Yan Wei, Jinchuan Hou, Di Huang, Weiyi Chen
Polymeric biomaterials are widely used in therapeutics [1,2] and diagnostics [3,4] as micro-nanobiosensors for cell-based assays, drug delivery, and tissue-engineering applications [5]. With the recent emergence of soft lithography, elastomers have become most common enabling materials for the widespread fabrication and microfabricated systems, such as hydrogels and poly-dimethylsiloxane (PDMS) [6]. As a three-dimensional structure, hydrogels have been widely applied in modern medicine, including regenerative medicine. Depending on the chemical nature of the polymer and the degree of its crosslinking, the properties of hydrogels matrices differ widely [7]. They are used mainly as drug carriers [8–10], in wound dressings [11–13], in contact lenses [6,14,15] or in gene therapy [16–18]. PDMS owns numerous advantages over traditional biomaterials. It is relative inexpensive, inert, nontoxic, and can be easily molded to form microstructures [19]. Despite these desirable properties, both hydrogels and PDMS share the disadvantage that they cannot be etched into individual microarray structures that separate from each other. Therefore, it is important to explore alternative biomaterials that can be used to manufacture multiple biomedical microdevices isolated from each other and for biological research analysis.