polymer based

A.Boustheen (a), F.G.A. Homburg (a), J.E. Bullema (b), A. Dietzel (a), (c)

(a) Micro and Nano Scale Engineering, Eindhoven University of Technology, The Netherlands
(b) TNO Science and Industry, Eindhoven, The Netherlands
(c) Holst Center, Eindhoven, The Netherlands

Abstract

Using active microvalves liquid flow in microsystems can be precisely controlled and timed. Plastic microfluidic networks offer high flexibility in the material selection and potentially also allow for low cost mass fabrication. For selecting a suitable micro-actuation scheme, the different options are compared on the basis of actuation performance parameters. For thermal-expansion, electrostatic, electroactive, piezoelectric and shape memory actuation principles the work density is derived from basic actuator physics and literature material parameters. For the targeted actuator dimensions also frequency, stroke and force characteristics are calculated. These are compared with actuator performance targets typical for micro-fluidic networks: forces between 160μN and 16mN, stroke of 50μm, repetition frequencies ranging from 100Hz to few mHz. As a result, only electroactive polymer and thermal actuation principles remain as viable options and shall in further work be experimentally evaluated using a modular design with interchangeable actuators.

P.J. Bolt, J.E. Bullema, R. Korbee, R. Kusters
TNO Science and Industry, Eindhoven, The Netherlands

Abstract

This paper concerns the feasibility of polymer capping of RF-MEMS devices, replacing traditional silicon solutions. The advantage would be less costs and potential for both further miniaturisation and integration of electrical functions in the cap. One of the challenges is the resistance against expoxy overmoulding as part of the traditional back-end process chain. This involves temperatures of 175oC and pressures of 10MPa, which the cap has to withstand. Calculations are made and experiments carried out to investigate the feasibility of selected polymers. It is shown that nanofillers will lift the polymers mechanical properties comfortably above the minimum established demands.

E. Ritzhaupt-Kleissla (b) J. Haußelta (b), T. Hanemanna (b)
a Forschungszentrum Karlsruhe, Institut f. Materialforschung III, D-76021 Karlsruhe, Germany
b Albert-Ludwigs-Universität Freiburg, Institut f. Mikrosystemtechnik (IMTEK), D-79110 Freiburg, Germany

Abstract

The influence of spherical ceramic nanoparticles as fillers in thermoplastics has been observed by several groups. It is expected to improve material properties of thermoplastics, e.g. hardness, glass transition temperature and thermal expansion coefficient, by incorporating nanosized ceramic particles into the polymer matrix. Nevertheless present literature does not give uniform statements.

In the current work a process chain for homogeneously dispersing inorganic nanosized particles as well as chromophoric dopants into a polymer matrix was developed. Plexit 55, a commercially available reactive resin based on PMMA diluted with MMA was used as polymer matrix. Different methods of dispersing the fillers were applied. Using either a high speed stirrer or a high pressure homogeniser, solid loads of inorganic fillers up to 10 wt% and organic filler contents up to 20 wt% were achieved. Dispersions were polymerised using a UV-photo moulding setup. Test specimens of thermoplastic nanofiller composites were replicated using plastic injection moulding. Resulting parts were investigated with regard to the influence of inorganic and organic fillers on materials’ glass transition temperature, molecular weight, rheological behaviour and thermal expansion coefficient.