Sensing temperature distributions over an area is of interest for many applications, and it is currently performed using sensors that are attached to the structure. In this work a conductive "smart paint", made from latex and exfoliated graphite, is introduced for temperature sensing. This provides, as an alternative to manual fixation, the ability to integrate sensors during fabrication because the approach is amenable to additive manufacturing technologies such as 3D printing. We demonstrate that calibration of the spray-coatable polymer/carbon composite thin film sensors allows accurate temperature measurement over an area. We further demonstrate continuous, distributed temperature sensing by employing electrical impedance tomography to reconstruct a thermal image from measurements at the perimeter of the sensing region. 1 Introduction Sensing temperature distributions over an area is of interest for applications ranging from environmental awareness in advanced robots to thermal management systems in satellites. This is currently achieved by arrangements of numerous single-point sensors, typically thermocouples, thermistors, and resistive temperature devices (RTDs). A high density of point sensors is required to measure steep temperature gradients that would otherwise put the system at risk of overheating. To form a more complete thermal image, arrays of sensors fabricated onto one substrate can be attached as a unit. Some distributed temperature measurement methods have been studied, including distributed fiber optic temperature sensors [1] and solar cells acting as capacitive temperature sensors [2].In this work we demonstrate that a grid of compliant polymer/carbon composite thin film sensors accurately measures temperature over an area, which can be converted into a thermal image of the surface. We further demonstrate continuously distributed temperature sensing using the functional paint over an area, applying electrical impedance tomography to reconstruct the temperature profile.Approaches that integrate the fabrication of thermal sensors into additive manufacturing provide a clear advantage over manual fixation and wiring. Because of the increasing use of 3D printing of polymeric structures (including even spacecraft components, which have been manufactured from ULTEM 9085 using fused deposition

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