A novel manufacturing strategy for bio-inspired cellular structures

This paper presents a novel manufacturing method for cellular materials with a graded porosity distribution. The motivation for creating a gradient of porosity in materials has been inspired by nature and aspires to mimic natural structures so their intrinsic advantages (e.g., optimised mechanical properties) can be exploited. Many engineering applications (e.g., thermal, acoustics, mechanical, structural and tissue engineering) require porosity tailored structures. However, current manufacturing processes are currently unable to mass-produce these foams. In this work, low power-low frequency ultrasonic irradiation has been used to excite polymeric foaming melts that, once solidified, contained different porosity distributions throughout in their solid matrix. This was possible by controlling the amount of energy imposed on the samples. The generation of porosity gradients that resembles those of natural cellular structures (e.g., bones, stems) opens up new opportunities in the design and manufacture of bio-inspired materials that can solve challenging technological problems.