The phase change of these TR-CPs upon heating was monitored visually and by variabletemperature rheology (Fig. ). We observed that the TR-CP with a mass ratio of PSS:PNIPAM of 1:2.3 (PEDOT:PSS96-b-PNIPAM440, Table , Entry 4) formed a gel at Tgel = 35 °C (Fig. ) as estimated from the crossover point between the storage (G') and loss (G") moduli. The solgel transition was found to be isovolumetric (Fig. ) and very rapid, with a gelation time of only 41s at 37 °C (Fig. and Supplementary Video 1). The storage modulus reached a plateau of 20 Pa at 37 °C, indicating the formation of a stable gel (Fig. ). The gel was also stable over a wide range of frequencies at 37 °C from 0.1 rad s -1 to 20 rad s -1 (Fig. ). To establish the reversibility of the sol-gel transition, a subsequent cooling ramp was performed. We observed that on cooling below the LCST, the storage and loss moduli returned to their original values in the solution state, with a slight hysteresis (Fig. ). Such hysteresis is observed commonly in other non-conductive thermo-responsive gels and can be eliminated by equilibration. We established that the TR-CP retained its reversible sol-gel transition under multiple thermal cycling events as seen over ten heat-cool cycles in the rheometer (Fig. and Fig. ). It was found that G" of the gel (50 °C) remained unchanged throughout the experiment. The storage modulus of the liquid increased slightly from 0.2 Pa to 0.4 Pa, likely caused by dehydration at prolonged exposure to temperatures above 40 °C. Anecdotally, we have performed more than these 10 thermal cycles in sealed vials without losing the reversible sol-gel transition. Importantly, the TR-CP can be lyophilized and re-dispersed in aqueous solutions, including aqueous buffers of varying pH, PBS, or cell media, without affecting its reversible sol-gel transition. We re-dispersed the TR-CP in water at pH 7, and on changing the concentration from 3.6 wt% to 5.6 wt%, a negligible increase in Tgel was observed to 36 °C (Fig. ). However, the gelation time at 37 °C decreased to 23 s, and the storage modulus increased by an order of magnitude to 200 Pa (Fig ), highlighting the possibility to control gelation time and gel stiffness simply by changing the TR-CP concentration in water. TR-CP gels at both concentrations were stable for at least 15 min at 37 °C (Fig. ), and for several months in a closed vial at room temperature. The quick gelation time, tunable storage modulus and good stability under shear are all desirable for bioelectronics, particularly to interface with soft tissues.