Liquid PMMA: A High Resolution Polymethylmethacrylate Negative Photoresist as Enabling Material for Direct Printing of Microfluidic Chips

Abstract

Polymethymethacrylate (PMMA) is one of the most important thermoplasts and a commonly used material in microsystem fabrication, for example, microfluidics owning mainly to its optical transparency, biocompatibility, low autofluorescence, and low cost. However, being a thermoplastic material PMMA is typically structured using industrial replication techniques making PMMA unsuitable for rapid prototyping. The fact that neither material nor processing technique can be directly transferred from laboratory to industrial state makes the research‐to‐business conversion often extremely difficult in microfluidics since material properties have a major impact on the final system behavior. This paper presents “Liquid PMMA,” a fast curing viscous PMMA prepolymer which can be used as a negative photoresist and directly structured using ultraviolet or visible light with tens of micron resolution and smooth surfaces. Using this technique microfluidic chips in PMMA can be fabricated within minutes. The cured Liquid PMMA parts show the same high optical transparency, low autofluorescence, and surface properties like commercial PMMA. In this way, microfluidic chips can be rapidly developed and optimized on the laboratory scale in the same material which is later on used on the industrial scale.

Making the best of it: nitroxide-mediated polymerization of methacrylatesviathe copolymerization approach with functional styrenics

“…S3-10 †). Concerning PMMA, being a material used for many optical applications 63,64 or simply when transparence in the final object is required along its particular properties, 62,[72][73][74] it is important to ascertain that its optical properties are not strongly impacted by the presence of the controlling comonomer. As a relevant reference sample, we synthesized a PMMA sample by ATRP (PMMA ATRP ), which does not necessitate the introduction of a controlling comonomer.…”

Microbioreactors as Engineering Tools for Bioprocess Development

“…In terms of the industrial baseline, thermoplastics such as PDMS and PMMA may be cost-effective but with the absence of a fast and robust process of fabrication. Even though soft lithography is a trend technique for laboratorial prototyping using PDMS, it still requires the master structure, which can demand an inconvenient amount of time to fabricate on the industrial level (Kotz et al, 2017). An alternative solution consists of adopting direct structuring approaches that use photocurable polymers able to be structured by light without the need of a master piece.…”

“…However, the number of adequate materials for these techniques is still limited, comprehending, most of the time, resins of undefined composition. As a consequence, it is extremely difficult to conduct the direct transference of prototypes on the laboratorial scale to the industrial state (Kotz et al, 2017).…”

Fused Deposition Modeling of Microfluidic Chips in Polymethylmethacrylate

“…PMMA prepolymers consisting of the monomer methylmethacrylate (MMA) and the polymer PMMA have been used for replication of microfluidic PMMA chips with high resolution from a variety of different master structures like polydimethlysiloxane (PDMS) or stainless steel [ 25 , 26 ]. Recently, we have introduced Liquid PMMA, a photocurable PMMA prepolymer which can be structured with tens of micron resolution using direct lithography [ 27 ]. However, all these rapid prototyping processes are only capable of fabricating open 2.5-dimensional microfluidic structures, which need to be closed during a subsequent bonding step.…”