(381h) Composite Bijels through Microfluidic Twisting

Bijels are soft materials with potential applications in membranes, micro reactors, energy and healthcare materials [1], but their low tensile strength makes reinforcement strategies imperative.

Here, we investigated a method to fabricate micro-ropes of nano-structured bijel fibers. This method shows how weak microfibers with tensile strengths of a few kPa [2] can be reinforced by 4 orders of magnitude by means of microfluidic twisting. Microfluidic twisting allows to produce continuous bijel fiber bundles of controllable architecture. Modelling the fluid flow field reveals the bundle geometry dependence on a subtle force balance composed of rotational and translational shear stresses. Moreover, combining multiple bijel fibers of different compositions enables the introduction of support fibers to raise the tensile strength to tens of mega pascals, while simultaneously preserving the liquid like properties of the bijel fibers for transport applications.

This microfluidic twisting can be used to combine fibers with different mechanical properties, chemical compositions and building blocks to generate multi-functional composite bundles with enhanced mechanical, transport and catalytic properties. Moreover, our method is fully applicable to fibers made of reconfigurable printed liquids, hydrogels, capillary suspensions, high-internal phase emulsions or colloidal gels.

References:

[1] M.F. Haase, K. J. Stebe, D. Lee, Advanced Materials (2015)

[2] M.F. Haase, S. M. Nima, D. Lee, K.J. Stebe, ACS Nano (2016)