# Direct-Write Dewetting of High Melting Temperature Metals on Flexible Substrates
## 5 Conclusions  
It has been demonstrated that at a very high melting point, high reflectivity metals such as Ni and Ag, respectively, may be dewetted into patterns via a scanning laser beam on flexible polymer substrates. High average powers are used to quickly heat the target films to their melting point, after which the spatial variation of the laser beam will induce a thermocapillary flow away from the center point of exposure. Substrate destruction is avoided by using a polymer with high transmittance at the laser operating wavelength and fast scan rates of the laser. Metals with elevated reflectivity rates can be patterned using increased laser intensities or by depositing thin NIR absorption layers, thereby lowering the required flux intensity by over a factor of 2.  
The use of the scan system allows for complex shapes to be dewetted into the metallic target layer to form patterned metallic films on flexible polymer substrates. Resistance measurements confirmed that a single pass of the laser leaves no connecting conductive material in the exposed area, thus ensuring electrically isolated features. Finally, by making partially overlapping passes, the dewetting high temperature metal can be \"pushed\" in a directional manner, which gives rise to thicker features without the need for additional deposition steps.  
The following are available online at [[http://www.mdpi.com/2076-3417/9/15/3165/s1](http://www.mdpi.com/2076-3417/9/15/3165/s1)]([http://www.mdpi.com/2076-3417/9/15/3165/s1](http://www.mdpi.com/2076-3417/9/15/3165/s1)). Figure S1: Ni films deposited to a thickness of (a) 320 nm on glass, (b) 320 nm on Par-C, and (c) 640 nm on Par-C. All lines processed using the laser at 10 W with 2.5 \(\upmu\)s pulses at 100 kHz. Films on glass were scanned at 0.3 m/s while films on Par-C were scanned at 0.2 m/s. All features are created at a 50 \(\upmu\)m line-to-line pitch. Figure S2: Bi-coated Ag films deposited on Par-C. Films were processed from the (a) \"front\" at 10 W where the Bi-film is directly exposed and from the (b) \"back\" at 40 W where the laser is routed through the glass and Par-C substrate to hit the Ag film directly bypassing the Bi film. Features are created using a 50 kHz, 5 us regime and scanned at various speeds. Figure S3: Ni-coated Ag films deposited on Par-C. Films were processed from the (a) \"front\" at 20 W where the Ni-film is directly exposed and from the (b) \"back\" at 40 W where the laser is routed through the glass and Par-C substrate to hit the Ag film directly bypassing the Ni film. Features are created using a 50 kHz, 5 us regime and scanned at various speeds.  
Conceptualization, G.G.A. and A.J.F.; methodology, A.J.F. and G.G.A.; formal analysis, A.J.F.; investigation, A.J.F. and A.H.; writing--original draft preparation, A.J.F. and G.G.A.; writing--review and editing, G.G.A. and A.J.F.; supervision and project administration, G.G.A.; funding acquisition, G.G.A.  
This research was funded by the US Government.  
The authors would like to thank [PERSON] and [PERSON] for technical assistance.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.