Monolithic growth of partly cured polydimethylsiloxane thin film layers

• Published in: Polymer journal Vol. 46; no. 2; pp. 123 - 129
• Main Authors: Yu, Liyun, Skov, Anne Ladegaard
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.02.2014; Nature Publishing Group
• Subjects: 639/301/119/544; 639/638/455/941; Adhesion; Applied sciences; Biomaterials; Bioorganic Chemistry; Chemical modifications; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Curing; Differential scanning calorimetry; Electroactive polymers; Exact sciences and technology; Inorganic and organomineral polymers; Laminates; original-article; Physicochemistry of polymers; Polymer Sciences; Scanning electron microscopy; Silicone resins; Surfaces and Interfaces; Thin Films; monolithic; adhesion; dielectric electroactive polymers; crosslinking; polydimethylsiloxane; Dimethylsiloxane polymer; Viscoelasticity; Adhesivity; Dielectric properties; Mechanical properties; Crosslinking; Hydrosilylation; Experimental study; Thermal stability; Transformation temperature; Thermal properties; Interface properties; Crosslinked polymer; Manufacturing; Interface reaction; Monolithic material; Bilayers
• ISSN: 0032-3896; 1349-0540
• DOI: 10.1038/pj.2013.72

The demand for monolithic structures in many applications has increased to enable more reliable and optimized performances such as for dielectric electroactive polymers (DEAPs). For the layers of the elements to grow efficiently together, it is first of all required that the layers adhere together to enable interlayer crosslinking reactions either by application of an adhesion promoter or by ensuring that there are reactive, complementary sites available on the two surfaces. Polydimethylsiloxane (PDMS) is a widely used polymer for DEAPs. In this work, two-layered PDMS films are adhered together at different curing times. The monolithic films are investigated by rheology, scanning electron microscope, mechanical testing, dielectric relaxation spectroscopy, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology, mechanical and dielectric properties, as well as thermal stabilities of the bilayer elastomer films are observed to change with the curing time of the monolayers before lamination. The objective of this work is to create adhesion of two layers without destroying the original viscoelastic properties of the PDMS films, and hence enable, for example, adhesion of two microstructured films which is currently a crucial step in the large-scale production of DEAPs. Monolithic polydimethylsiloxane (PDMS) thin film layers were prepared by adhering two partly cured films together at different curing times. For dielectric electroactive polymer (DEAP) uses the lamination performed slightly above the gelation threshold, namely at the time where the monolayer films had gained 30% of the final mechanical strength, was extremely favorable. The lamination process for DEAP bilayers can actually be used as a process to improve the overall performance of the DEAP, and hence enable the large-scale production of DEAP transducers.