Self-assembly Behavior of Amphiphilic Janus Particles in the Acting Process of Breath Figure Method

Breath figure ( BF ) method is a dynamic templating method for surface patterning of polymeric materials. The BF process has been extensively studied as a novel methodology to achieve surface patterning via self. assembly. During the evaporation of the solvent, functional buliding blocks added into the casting solution such as nanoparticles, block copolymers and other components containing hydrophilic parts could be able to spontaneously migrate onto the water/oil interfaces formed between templating water droplets and casting solution during the BF process. As a result, functionalization and modification of the obtained patterned surfaces on selective areas could be achieved at the time when matrices of patterned surfaces are formed. By employing the particles in BF method, the porous film with pore arrays selectively decorated with particles can be fabricated. Based on the combination of interfacial self. assembly of particles and self. assembly process of BF, amphiphilic Janus particles were employed in the breath figures method. Amphiphilic Janus silica particles were prepared by selective chemical treatment on the particle "colloidosomes". Janus particles enriching the patterned pores present unique assembling characteristics which are much different from previously reported cases with homogeneous particles. The experimental results indicate that Janus particles show optimized assembling morphology when they are involved in the interfacial self. assembly process of BF. By employing Janus particles, a trade. off of the ordering of the honeycomb. structured pore arrays and the density of decorated particles was also achieved. With lower concentration of particles being used, Janus particles show quite different assembling behavior from their homogeneous counterparts. It opens an attractive route to produce functional hierarchically patterned materials by, for example, loading the biological Janus particles for single. cell cultures or catalytic Janus particles for micro. chemical reactors.