Fig. 4: Gel behavior of upconversion particles-assisted NIR polymerization. | Nature Communications

Fig. 4: Gel behavior of upconversion particles-assisted NIR polymerization.

From: Upconversion particle-assisted NIR polymerization enables microdomain gradient photopolymerization at inter-particulate length scale

Fig. 4: Gel behavior of upconversion particles-assisted NIR polymerization.

a Schematic presentation of the gelation process. b Example of photorheology test for gel point detection using 1 wt% UCPs formulation (NIR intensity 25 W/cm2). c Time to gel point (tg) and gel point conversion (Cg) at different UCPs concentrations (25 W/cm2) and at (d) different NIR intensities (2 wt% UCPs). The error bars represent the standard deviations. e Comparison of gel point conversion (Cg), time to gel point (tg) and final conversion (Cf) under three different curing conditions: NIR, UV and UV coupled with heating (NIR 25 W/cm2, 1 wt% UCPs, UV 8 mW/cm2, heating to 60 °C). f Tan(δ) as a function of temperature for a resin (1 wt% UCPs) cured under NIR and UV respectively (NIR 25 W/cm2, UV 8 mW/cm2 at 25 °C). g Conversion-time profiles at different ambient temperatures under UV irradiation (8 mW/cm2).

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