Grow with the flow – observing the formation of rheotactically patterned bacterial cellulose networks

Abstract

Rheotactic structures: hierarchically and anisotropically structured textiles obtained by the growth of bacterial cellulose under flow, constituting porous substrates for potential applications as e.g. adsorbents or mineralization templates.

Threedimensionally patterned, hierarchically and anisotropically structured bacterial cellulose

“…Their assessment is somewhat complicated by the local presence of birefringence in the resin matrix, assumed to signify curing stresses. Nevertheless, it is apparent from the majority of orange-colored cellulose that the molecular axes are parallel to the slow axis of the retardation plate, and therefore to the former direction of flow, in agreement with our observations in earlier works [10]. Notable exceptions are the portions of the gyroid structure that connect perpendicular to the former direction of flow, as sketched in the right-hand columns of figure 5.…”

“…In earlier works, we observed preferred orientation of fibers on the nanometer scale in compact BC films [9] and the formation of superstructural patterns on the centimeter scale in BC strands [10] when grown under flowing nutrient medium, which we termed rheotactic growth. In both cases, shear flow-inducing obstacles were used as anchoring points for the forming BC.…”