Experimental and numerical study on the viscoelastic property of polycarbonate near glass transition temperature for micro thermal imprint process

Lan, Shuhuai; Lee, Hey Jin; Lee, Soo Hun; Ni, Jun; Lai, Xinmin; Lee, Hyoung Wook; Song, Jung Han; Lee, Moon Gu

doi:10.1016/j.matdes.2009.03.045

Cited by 46 publications

(32 citation statements)

References 8 publications

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“…Generally, there are three stages (i.e., the glassy state, rubbery state, and viscous state) that thermoplastic polymers experience in sequence with a gradual increase of the heating temperature [45]. When thermally annealed at a temperature above the T g of PSt, PSt microspheres enter the rubbery state, in which they undergo viscoelastic deformation.…”

Section: Resultsmentioning

confidence: 99%

Ordered arrays of pumpkin-shaped Janus particles with tailored surface morphologies via microcontact hot embossing

Wang

Xie

et al. 2015

Colloid Polym Sci

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In this paper, we report the controlled fabrication of ordered arrays of pumpkin-shaped (i.e., shapes having the equatorial diameter greater than the polar diameter and being flattened at the poles) Janus polystyrene (PSt) particles with tailored morphologies. It is based on simple microcontact hot embossing of monodispersed PSt microsphere monolayers using different stamps such as glass slides, colloidal sphere monolayers, and wrinkled sheets. The resultant pumpkinshaped particles have the stamp-defined surface topographies, with one side flat and the other flat or patterned with small beads/holes and striped/dotted bulges. We systematically investigate the effect of the embossing conditions on the surface morphologies, which include the annealing temperature/time, the external load, and the structured stamps. Benefiting from the hexagonal close packing of original symmetric microspheres, well-ordered Janus particle arrays are obtained using the combined bottom-up/topdown strategy. Compared with the traditional two-stage process of fabrication and self-assembly, this method is much simpler and more straightforward, which is of significant importance for the related applications.

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Section: Resultsmentioning

confidence: 99%

Ordered arrays of pumpkin-shaped Janus particles with tailored surface morphologies via microcontact hot embossing

Wang

Xie

et al. 2015

Colloid Polym Sci

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“…First, a 500µm thin PMMA substrate and the silicon stamp were heated to a temperature of 140°C during the heating step. At this temperature, the used thermoplastic reaches its rubbery state [3] and is suited for pattern replication. During the following embossing step, an embossing force of 4kN was applied between the stamp and the PMMA substrate and maintained for 2 minutes, thus transferring the stamp structures on the PMMA surface.…”

Section: Fabricationmentioning

confidence: 99%

Low-cost fabrication of optical waveguides, interconnects and sensing structures on all-polymer-based thin foils

et al. 2016

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Micro-optical sensors based on optical waveguides are widely used to measure temperature, force and strain but also to detect biological and chemical substances such as explosives or toxins. While optical micro-sensors based on silicon technology require complex and expensive process technologies, a new generation of sensors based completely on polymers offer advantages especially in terms of low-cost and fast production techniques. We have developed a process to integrate micro-optical components such as embedded waveguides and optical interconnects into polymer foils with a thickness well below one millimeter. To enable high throughput production, we employ hot embossing technology, which is capable of reel-to-reel fabrication with a surface roughness in the optical range. For the waveguide fabrication, we used the thermoplastic polymethylmethacrylate (PMMA) as cladding and several optical adhesives as core materials. The waveguides are characterized with respect to refractive indices and propagation losses. We achieved propagation losses are as low as 0.3 dB/cm. Furthermore, we demonstrate coupling structures and their fabrication especially suited to integrate various light sources such as vertical-cavity surface-emitting lasers (VCSEL) and organic light emitting diodes (OLED) into thin polymer foils. Also, we present a concept of an all-polymer and waveguide based deformation sensor based on intensity modulation, which can be fabricated by utilizing our process. For future application, we aim at a low-cost and high-throughput reel-to-reel production process enabling the fabrication of large sensor arrays or disposable single-use sensing structures, which will open optical sensing to a large variety of application fields ranging from medical diagnosis to automotive sensing.

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“…The modulus and viscosity are further reduced in this region and the deformation is thus irreversible (Guo, 2004;Lan et al, 2009). The Young's modulus for glassy polymers below T g is approximately constant over a wide range of temperature and the magnitude of deformation is very small.…”

Section: Thermal Behavior Of Polymeric Materialsmentioning

confidence: 99%

Embossing Process

Lin

2016

Printing on Polymers

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Experimental and numerical study on the viscoelastic property of polycarbonate near glass transition temperature for micro thermal imprint process

Cited by 46 publications

References 8 publications

Ordered arrays of pumpkin-shaped Janus particles with tailored surface morphologies via microcontact hot embossing

Ordered arrays of pumpkin-shaped Janus particles with tailored surface morphologies via microcontact hot embossing

Low-cost fabrication of optical waveguides, interconnects and sensing structures on all-polymer-based thin foils

Embossing Process

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