Ethyl cyanoacrylate ordered porous films prepared via in‐situ polymerization and static breath figures process

Abstract

Ordered microporous films were fabricated via static breath figure process and in situ polymerization of ethyl cyanoacrylate (ECA) monomers. The influences of various parameters including solvent type (dichloromethane and chloroform), ECA concentration (0.2 and 1 wt%), temperature (17°C and 26°C), and substrate (glass, mica, PE, PP, and PET) were investigated on the structure of breath Figure (BF) films. Highly ordered porous films were generally formed at lower concentration of ECA and at 17°C for dichloromethane (DCM) and at 26°C for chloroform (CLF). The pores average diameter (D̅) of the films were in the range of 1 to 5 μm. The formation of regular porous structures were elucidated using the Marangoni (thermocapillary) convection flow and the rate of the polymer precipitation around the water droplets. There were an optimum ΔT (the temperature difference between the air and the solution surface) to create ordered BF film, regardless of solvent type. The prepared films have potential for templating applications.

Exploiting breath figure reversibility for in situ pattern modulation and hierarchical design

“…Under optimised material and environmental conditions, stabilised condensation droplets in classical BF grow mainly by diffusion, forming monodisperse HCP with negligible coalescence between droplets. 26 In contrast, the condensation droplets in our BF patterns appear at high initial nucleation density and grow due to diffusion and significant coalescent events. Fig.…”

“…58 However, when droplets pack closely, their growth is accelerated due to the coalescence between neighbours, yielding a self-similar growth regime in which droplet diameters follow D L p t. 36 Under optimised material and environmental conditions, stabilised condensation droplets in classical BF grow mainly by diffusion, forming monodisperse HCP with negligible coalescence between droplets. 26 In contrast, the condensation droplets in our BF patterns appear at high initial nucleation density and grow due to diffusion and significant coalescent events. Fig.…”

“…The facile nature of the classical BF approach lends itself to the passive coupling between the solvent evaporation and polymer curing that foresees both the initiation of condensation and termination of droplet growth with the curing of the pattern. [17][18][19][20] While offering opportunities to create varied selfassembled patterns, [21][22][23] this complex interconnection between the dynamic and non-equilibrium condensation/evaporation processes restricts the direct translation of the mechanistic knowledge of drop-wise condensation kinetics 24 towards predictive design of pore size and spacing in the classical evaporation-driven BF 21,25,26 approach. Substituting the passive evaporation-driven cooling of the polymer interface with external film cooling, we eliminate the coupling and enable in situ interrogation and modulation of the BF patterns through access to discrete intermediate designs within a single dynamic process.…”