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PATTERNING ELASTOMER, THERMOPLASTICS AND SHAPE MEMORY MATERIAL BY UVO LITHOGRAPHY AND SOFT LITHOGRAPHY

Chen, Ying
http://rave.ohiolink.edu/etdc/view?acc_num=akron1491264216402058

Abstract Details

2017, Doctor of Philosophy, University of Akron, Polymer Engineering.
Micro/nano patterning and structures, especially hierarchical structures have attracted great research interest in the past few decades, because these structures exhibit unique properties like tunable adhesion and wetting. Especially, micro/nano patterning is of great interest for semiconductor, micro/nano fluidics, optical and photonic devices applications. Traditional methods used for the fabrication of hierarchical structures typically involve the formation of complex patterned features through multistep lithography processes. These methods usually require expensive equipments and specialty reagents, so that the low-cost fabrication of well-controlled micro-nano patterns for diverse potential applications remains a challenge. We demonstrated a versatile and inexpensive method for controlling the surface relief structure of polymer films over large areas through a two-step imprinting process. First, nanoscale patterns were formed by nanoimprinting elastomer (PDMS) films with a pattern on a DVD disk. Micron-scale patterns were then superimposed on the nanoimprinted PDMS films by exposing them to ultraviolet radiation in oxygen (UVO) through a photomask. UVO exposure leads to a conversion and densification of PDMS to SiOx, leading to micron height relief features that follow a linear scaling relation with pattern dimension. Further, the pattern scopes are shown to collapse into a master curve by normalized feature values. Interestingly, these relief structures preserve the nanoscale features. In this dissertation, the influence of the self-limiting PDMS densification, walls stress at the boundary of micro depression, PDMS thickness, modulus and UVO exposure energy is studied in control of the micro depression scale. The method fidelity was evaluated in coarse-grained molecular dynamics simulations and confirmed experimentally. In the second part of this study, this simple two-step imprinting process involving both nanoimprinting and UV radiation, is studied for pattern transfer demonstration of the dimension adjustable micro-nano hierarchically structures not only on elastomer films, self-assembled monolayer and nanoparticles but also by imprinting onto thermoplastic polymer films. The patterning of thermoplastic polymer films is achieved through capillary force lithography (CFL). Fundamental study of CFL is conducted to understand the influence of film thickness and annealing process. Another two forms of soft lithography examined here include replica molding, and microcontact printing. Thus, these generated patterns are successfully extended to self-assembled monolayer and nano particles, which enlightens the further potential applications of the proposed patterning method. Finally, Shape memory compounds based on mixtures of an ionomer with a FA are used to develop shape memory or shape morphing surfaces with micro- or nano-scale features. Three different FAs, zinc stearate (ZnSt), stearic acid (SA) or lauric acid (LA) are mixed with Zn salt of sulfonated EPDM, respectively, to act as the temporary networks. As with the bulk shape memory compounds based on the ionomer/FA design, the switching temperature for micro- and nano-scale surface pattern recovery can be easily tuned by simply changing the FA used in the composition. The shape memory recovery efficiency of the micro and nano scaled surface topography is compared with bulk materials. The recovery behavior for the surface nanopattern, however, had lower efficiency than micropattern scale and bulk shape memory of the same material, which may be due to the effects of the excess surface energy on the dynamics of the surface patterns or creep of the temporary or permanent networks due to the high stress used to deform the nano-scale grating pattern and produce the temporary crosshatched pattern.
Alamgir Karim (Advisor)
Abraham Joy (Committee Member)
Kevin Cavicchi (Committee Chair)
Xiong Gong (Committee Member)
Jutta Luettmer-Strathmann (Committee Member)
Polymers

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Citations

  • Chen, Y. (2017). PATTERNING ELASTOMER, THERMOPLASTICS AND SHAPE MEMORY MATERIAL BY UVO LITHOGRAPHY AND SOFT LITHOGRAPHY [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1491264216402058

    APA Style (7th edition)

  • Chen, Ying. PATTERNING ELASTOMER, THERMOPLASTICS AND SHAPE MEMORY MATERIAL BY UVO LITHOGRAPHY AND SOFT LITHOGRAPHY. 2017. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1491264216402058.

    MLA Style (8th edition)

  • Chen, Ying. "PATTERNING ELASTOMER, THERMOPLASTICS AND SHAPE MEMORY MATERIAL BY UVO LITHOGRAPHY AND SOFT LITHOGRAPHY." Doctoral dissertation, University of Akron, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1491264216402058

    Chicago Manual of Style (17th edition)

akron1491264216402058
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