Thermocapillary approaches to the deliberate patterning of polymers

Abstract

The phenomenon of thermocapillarity, the response of fluids to thermal gradients due to thermal alteration of their surface tension, was first reported over a century ago. Since then, research has focused generally on either the fundamentals or mitigation of this effect during the processing of materials. Only in the past two decades has the deliberate use of thermocapillary forces for the patterning of polymers been actively pursued, either for the ordering of internal structure or the introduction of topographic features. This review seeks to highlight this work and to identify directions for further investigation. In particular, while thermocapillary forces are often inextricably bound to other mechanisms, there are emerging directions in the deliberate coupling of forces to improve the capabilities of each mechanism. Further, the applications of thermocapillary patterning to polymer-nanoparticle composites has recently provided another promising route to active architectures.

Macroscopic Alignment of Block Copolymers on Silicon Substrates by Laser Annealing

“…The rise in temperature over the ambient value, Δ T , caused by laser illumination, rather than the absolute temperature value, is shown in the plot to facilitate conversion between different power of illumination and changes in absorption due to the presence of an antireflective BCP layer. 88 …”

Subnanometer imaging and controlled dynamical patterning of thermocapillary driven deformation of thin liquid films

“…Furthermore, while TC-induced patterning has received significant attention in the past, mostly in the context of thin polymer film molding, where TC flows are triggered only in regions where the polymer film is above the glass phase transition temperature 16 (and also ref. 17 and references therein), we here leverage the ability to induce optically desired heating patterns to demonstrate the formation of light-induced droplets of different size directly from TLD film and their translation along the substrate (see also ref. 18 and ref.…”

Application of Plasmon-Induced Lithography for Creation of a Residual-Free Pattern and Simple Surface Modifications

“…18−22 This was implemented through the application of laser annealing of bottom substrates, initiating the flow of metal-coated polymers. 19,23 The local temperature spike at the laser spot leads to rapid local heating followed by a rapid temperature drop, which is the driving force for polymer flow. 19,20 The use of such a laser-based route for thin polymer film patterning is advantageous for its high speed and the ability to form a structure with arbitrary shape and last but not least cost- and time-efficiency.…”

“…19,23 The local temperature spike at the laser spot leads to rapid local heating followed by a rapid temperature drop, which is the driving force for polymer flow. 19,20 The use of such a laser-based route for thin polymer film patterning is advantageous for its high speed and the ability to form a structure with arbitrary shape and last but not least cost- and time-efficiency. 24,25 To ensure the effective laser patterning of the polymer and produce the thermal gradient, the efficient absorption of laser energy should be guaranteed.…”