Sugar-templated conductive polyurethane-polypyrrole sponges for wide-range force sensing

Abstract Porous conductive polyurethane (PU) sponges were prepared by combining a sugar-templated fabrication of porous polyurethane elastomer and the in-situ polymerization of pyrrole inside the sponges. The conductive sponges had a uniform porous structure similar to the sugar cube templates and a unique micro-wrinkled structure of polypyrrole (PPy). Moreover, the conductive sponges exhibited good mechanical properties and electrical conductivity by the combination of elastomeric PU and conductive PPy, which make the conductive PPy-PU sponges as good candidates for pressure and strain sensitive materials. It was shown that a single PPy-PU conductive sponge was not only sensitive to large forces, but also sensitive to the tiny deformation by small forces such as 0.1 N, thus realizing a wide-range detection of pressure forces from 0.1 N to 200 N. Furthermore, the detection range could be further enlarged to more than 800 N by assembling a sponge array. A PPy-PU sponge matrix was also designed and showed potential application in multi-site position detection. These sugar-templated conductive sponges may find application for sensors in human physiological movement and intelligent monitoring.