Organic Primitives: Synthesis and Design of pH-Reactive Materials using Molecular I/O for Sensing, Actuation, and Interaction

TL;DR

This paper introduces Organic Primitives, a set of pH-sensitive, organic-based sensor-actuators that enable new human-computer interaction modalities through color, shape, and odor changes, with applications across various fields.

Contribution

It presents novel organic, fluid-based sensor-actuators using food-grade molecules for pH-responsive outputs, expanding the toolkit for interactive material design.

Findings

Materials exhibit reversible pH-dependent color, shape, and odor changes.

The sensor-actuators operate effectively within pH 2-10 range.

Design techniques enhance functionality and control of the primitives.

Abstract

In this paper we present Organic Primitives, an enabling toolbox that expands upon the library of input-output devices in HCI and facilitates the design of interactions with organic, fluid-based systems. We formulated color, odor and shape changing material primitives which act as sensor-actuators that convert pH signals into human-readable outputs. Food-grade organic molecules anthocyanin, vanillin, and chitosan were employed as dopants to synthesize materials which output a spectrum of colors, degrees of shape deformation, and switch between odorous and non-odorous states. We evaluated the individual output properties of our sensor-actuators to assess the rate, range, and reversibility of the changes as a function of pH 2-10. We present a design space with techniques for enhancing the functionality of the material primitives, and offer passive and computational methods for controlling the material interfaces. Finally, we explore applications enabled by Organic Primitives under four contexts: environmental, cosmetic, edible, and interspecies.