Abrasion tolerant, non-stretchable and super-water-repellent conductive & ultrasensitive pattern for identifying slow, fast, weak and strong human motions under diverse conditionsElectronic supplementary information (ESI) available: The attached supporting information accounting materials and methods, synthesis of AGO, preparation of chemically reactive ink, fabrication of the superhydrophobic and conductive patterned interface, Table S1 and Fig. S1–S20 illustrating the performance of strain sensors, finger wiping test, FTIR of APTMS, impact of concentration of AGO on resistance, deposition of chemically reactive conductive ink and its post modifications, physical abrasion tests on superhydrophobic & conductive interfaces, tolerance under different aqueous exposures, stability of the interface at different temperatures and humidity, changes in the number of cracks and their width, coating on different substrates, estimation of response and recovery time, changes of resistance with the

The conversion of mechanical deformation into electrical signals is a widely used principle for various relevant applications. Facile & scalable fabrication, ultrahigh-sensitivity, low-response time and uninterrupted performance under severe conditions are hallmarks of an efficient strain-sensor that would be suitable for realistic application. In the past, various approaches were introduced to achieve high gauge factor—mainly associated with a large tensile deformation. But, in reality, a flexible strain sensor that displays a high gauge factor at low applied strain and remains efficient under practically relevant diverse and challenging conditions would be more appropriate for unambiguous and effective monitoring of human motions and other relevant applications. But, a low-strain sensor with ultrahigh sensitivity and durability is yet to be introduced in the literature. Here, a metal-free, chemically reactive and conductive ink is unprecedentedly introduced following a 1,4-conjugate addition reaction. Furthermore, a strategic integration of a chemically reactive porous paper with the prepared conductive ink allowed the development of a chemically reactive and conductive interface that allowed desired post covalent modification with selected alkylamines under ambient conditions. Taking advantage of the spatially selective deposition of the prepared ink on chemically recative paper and the ability of post covalent modification of the prepared ink, an abrasion tolerant superhydrophobic & conductive patterned interface was developed for achieving a low-strain (below 0.2%) based flexible strain sensor with an ultrahigh sensitivity (gauge factor ∼18 300) and low response time (8 ms). The external low-strain induced cracks on the flexible & durable superhydrophobic and conductive patterned interface provided a facile basis for real-time & wireless monitoring of slow, fast, weak and strong human motions & expressions—under diverse conditions, including continuous aqueous exposures, physical abrasions etc.