吸湿滞后驱动间歇性盐蠕变
Hygroscopic hysteresis drives intermittent salt creeping
浏览论文内容
中文总结 AI 辅助
研究盐蠕变动力学为何有时平滑有时间歇性的问题，通过研究毛细管中盐溶液受限蒸发，结合实验与理论模型，发现吸湿滞后能使稳定蒸发变为间歇性蠕变，将盐蠕变重塑为弛豫振荡器，指出滞后相变是蒸发多组分流体间歇性的通用途径。
中文摘要 AI 辅助
盐蠕变是指盐晶体从蒸发的液体界面沿周围表面沉淀的现象，存在于从地质和文化遗产风化到喷墨打印和碳封存等各种场景中。但其动力学有时平滑有时剧烈间歇性的原因一直未得到解释。本文研究了毛细管中盐溶液的受限蒸发，发现盐蠕变是一个内在间歇性的非平衡过程。通过系统改变初始盐浓度和环境相对湿度，确定了晶体在毛细管外表面沉积与非单调、间歇性动力学相关的状态。时间分辨测量表明，间歇性动力学由水间歇性吸收入毛细管外表面生长的盐结构维持，在蒸发和结晶之间建立了自放大反馈。结合实验和最小理论模型表明，潮解和风化浓度之间的滞后足以产生振荡盐积累和间歇性动力学。吸湿滞后是将稳定蒸发转变为间歇性蠕变的开关。结果将盐蠕变重塑为一个弛豫振荡器，并指出滞后相变是蒸发多组分流体中间歇性的通用途径。
英文摘要
Salt creeping -- the precipitation of salt crystals away from an evaporating liquid interface along surrounding surfaces -- occurs across settings from geology and cultural-heritage weathering to inkjet printing and carbon sequestration. Yet why its dynamics are sometimes smooth and sometimes violently intermittent has remained unexplained. Here we investigate the confined evaporation of salt solutions from a capillary with unidirectional water loss and show that salt creeping is an intrinsically intermittent, out-of-equilibrium process. By systematically varying the initial salt concentration and the ambient relative humidity, we identify regimes in which crystal deposition on the outer capillary surface goes hand in hand with non-monotonic, intermittent dynamics. Time-resolved measurements reveal that these intermittent dynamics are sustained by episodic water imbibition into the growing salt structures on the outer surface of the capillary, which sets up a self-amplifying feedback between evaporation and crystallization. Combining experiments with a minimal theoretical model, we demonstrate that hysteresis between deliquescence and efflorescence concentrations is sufficient to generate oscillatory salt accumulation and intermittent dynamics. Hygroscopic hysteresis, in other words, is the switch that turns steady evaporation into intermittent creeping. Our results recast salt creeping as a relaxation oscillator, and point to the hysteretic phase change as a generic route to intermittency in evaporating multicomponent fluids.
