Nanostructured Temperature Indicator for Cold Chain Logistics

Abstract

Food, chemicals, agricultural products, drugs, and vaccines should be transported and stored within an appropriate low-temperature range, following cold chain logistics. Violations of the required temperature regime are generally reported by time−temperature indicators; however, current sensors do not cover a sufficiently broad lowtemperature range and may lack thermal and photostability. Here, we report a nanostructured solvatochromic temperature indicator formed from cellulose nanocrystals decorated with carbon dots (C-dots). The indicator utilizes a strong nonlinear dependence of photoluminescence of C-dots on the composition of water/dimethyl sulfoxide (DMSO) solvent and a composition-dependent variation of the melting temperature of the water/DMSO mixture. Exceeding the temperature of the frozen mixed solvent above a designated threshold value results in solvent melting, flow, and impregnation of the nanostructured film, thus causing an irreversible change in the intensity and wavelength of photoluminescence emission of the film, which is reported both qualitatively and quantitatively. The indicator covers a temperature range from −68 to +19 °C and is cost-efficient, portable and photo-and thermostable.

Self-Destructive Structural Color Liquids for Time–Temperature Indicating

“…Notably, the triggering agent diffusion-induced structural color destruction can be further revealed by the λ max -time–temperature relationship, which demonstrates that the self-destruction progresses within a shorter time as exposure to a higher temperature based on diffusion kinetics and Brownian motion (Figure A,B). Compared to previous material-based TTIs − , and temperature-responsive structural color materials, ,,− our structural color liquids for visibly indicating time–temperature history demonstrate outstanding overall performances in inherent irreversibility, high sensitivity, tunable self-destructive time (40 min ∼ 5 days), and wide tracking temperature range (−70 ∼ +37 °C) even at low temperatures (Figure C,D), which are critical for indicating the time–temperature history of vaccines yet is impossible for conventional TTIs (Tables S1 and S2).…”

Solid-Emission-Tunable Squaraine with Thermal-Promoted Aggregate-State Transitions for Fast Thermal History Sensing

“…The determination of thermal-exposure history is of critical importance for many industrial processes in aeronautical science, automobile engineering, and electronic materials, where temperature is a key parameter for design, control, and durability. − Various strategies have been employed to track the thermal history, such as irreversible thermochromic coatings that undergo sublimation or chemical reactions at elevated temperatures with distinct color changes. − Luminescent materials with high spatial and temporal resolutions are more sensitive to temperature changes − and can uncover the thermal history more precisely, assisting the detection of localized overheating traces, which are crucial for diagnosing small electronic component malfunctions . Most reported luminescent thermal history indicators are based on inorganic materials, such as rare earth elements, which are only suitable for detecting ultrahigh temperatures of up to 1000 K and require long exposure times for luminescence response due to their structural rigidity. − By comparison, organic materials offer structural diversity, less toxicity, and low cost; however, most organic materials suffer from significant emission quenching at high temperatures due to thermal-promoted nonradiative relaxations, − limiting their applications in recording high-temperature thermal history.…”

Green synthesis of a thermo/photochromic doped cellulose polymer: a biocompatible film for potential application in cold chain visual tracking

“…on On the other hand, colorimetric sensors offer affordable and userfriendly monitoring without the need for read-out devices or trained personnel, 21,22 whereas, most of the indicators on the market are based on pigments/mixtures that degrade with increasing temperature, posing, thus, limits on reutilization. Alternatives based on nanoparticles that exhibit fluorescence changes due to temperature variations have been proposed recently in the literature; [21][22][23][24] however, their synthetic procedures and implementation into devices remain pretty challenging. Therefore, finding affordable, easy-to-synthesize materials for colorimetric sensors in the cold chain is crucial.…”