Hot embossing of PTFE: Towards superhydrophobic surfaces

Durable superhydrophobic PTFE films through the introduction of micro- and nanostructured pores

“…The surface of a PTFE plate has a static water CA of ∼108 • , and a SA >90 • , indicating water adhesion to the PTFE surface [16,17]. Much study has been devoted to the use of the PTFE surface to achieve superhydrophobicity [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], including plasma modification [18][19][20], thin film deposition [21,22], cold pressing and sintering [23], sandpapering [24], filter paper templating [25], hot embossing [26], PTFE-polymer phase separation [27][28][29][30], the formation of a PTFE-carbon nanotube composite plate [31], electrospray formation [32], axially stretching porous films [33], RF sputter deposition onto porous Al surfaces [34], and a two-step process with plasma etching and a nanoparticle assembly template to create controllable surface roughness [35]. Based on these studies, the key preparation requirement appears to be the development of a micro-and nanostructured surface.…”

Thermal stability of micro–nano structures and superhydrophobicity of polytetrafluoroethylene films formed by hot embossing via a picosecond laser ablated template

“…Among these proposed methods, templating is an attractive approach to realize superhydrophobic PTFE for its capacity in high efficiency and potential mass fabrication. Victor Jucius et al [22] presented a hot embossing method toward hydrophobic surface by using a Ni and a chrome template in generating the micro-nano structures on PTFE surfaces. The Ni template was fabricated by optical lithography with 2D micro-scale array of square pits and chessboard-like pattern.…”

“…Moreover, PTFE possesses a low free surface energy [15], the contact angle measured on its flat surface is about 110 • , making PTFE a good candidate for superhydrophobicity, which could significantly enlarge its application areas like potential "self-cleaning" windows, anti-icing, reduction of fluid resistance, etc. In recent years, some approaches have been reported to obtain a superhydrophobic polymer by packing of grains (sol-gel) [16,17], spraying [18,19], pressing (template) [20][21][22][23], etching [12,24,25], etc. Among these proposed methods, templating is an attractive approach to realize superhydrophobic PTFE for its capacity in high efficiency and potential mass fabrication.…”

Process parameter effects on dimensional accuracy of a hot embossing process for polymer-based micro-fluidic device manufacturing

“…Manufacturing by hot embossing rather than injection moulding is advantageous because of its relatively low cost for embossing tools, flexibility offering choice of embossing material and high replication accuracy for small features [15][16][17]. In addition, the temperature variation range for the polymer is smaller than that required in injection moulding, which leads to reduction in shrinkage during cooling.…”