RHEO-COOLING IS…COOL! J.P. Ibar New School Polymer Physics "Rheo-cooling" stems from the idea to use Rheology add another dimension process of cooling. For example, a liquid becomes solid if it is cooled below its solidification temperature: water ice freezing temperature. Ice can be shaped into cubes by cooling which has been poured an compartment. This really basis any molding process: take liquid, pump mold cavities, cool until solidifies, and then eject mold; object with given shape produced. In using mold, used for two purposes: shapes object, but also cools heat transfer surfaces solid. The classical method or place in contact cooler warmer surface. Most modern technologies apply this conduction via surface contact. Calories are transferred out warm cold ones, that plastic instance, conductive cooling, is, calories. bulk volume part being cooled, convection occurs. Although function taking at part, convective generally very slow. It should emphasized there considerable advantage material rapidly. technology called quenching". when quickly, as freezer, produce cubes, creates translucid solid, cube. Snow form solidification, course crystals appear quite differently snow than obtained as an ice cube. This is because the rain drops have had time to fall through several layers of cold atmospheres where cooling process much slower than in a deep freezer. As general rule, rate materials from liquid temperature solid has tremendous effect on material's morphology, structure, and therefore properties which formed. For example, snow ball cube don't same mechanical resistance. All solids are influenced by cooling. If one were capable extremely quickly, say at infinite rate, it would be possible preserve state, that get homogeneity for liquid. To illustrate this point further, should visualize metal without single crystal, metallic glass, novel extraordinary properties: no more corrosion around spherulites, new electrical magnetic properties. The implications bulk super-quenching opens up completely era material performance. Rheo-was born circumvent some limitations conductive/convective difficulty conventional heat transfer conduction relatively consuming process, unless works with highly conductive materials, like metals, or very thin samples, splat quench technologies. Plastics large capacity bad conductivity, two factors do not favor transfer. So problem plastic if wants cool them quickly must work films. Furthermore, difficult apply fast treatments, even films, poor efficiency of the process transferring calories by conduction for plastic materials. Cooling conduction/convection yields inhomogeneous and anisotropic morphologies. For example, if one takes an ingot steel which has started to cool, core is still hot when layers near edges are solid as a result contact with ambient air. So whole ingot, which, cold, represents object, parts have solidified before others. Some crystals had more time grow than others, because longer they stay at given temperature, grow. As consequence, there distribution sizes spherulites inside structure, resulting in internal stresses, gradients some sort, microcracks around spherulites' boundaries, yielding object weak resistance corrosion mechanical stress. Type video link below see Rheo-action: 1 liter water less 5 sec I want demonstrate cooling example: solidification contained round flask about seconds! actually made experiment it worked. The amazing watch illustrate idea. In case water, used fact that temperature solidification, Tc, was function concentration CO2 dissolved it. Even only 2 bars on top closed volume good shake dissolve liquid, could depreciate Tc 3 4 oC. other words, no 0 oC ( freezing water), but -3.5 you see, beginning, two handheld thermometers, reading refrigerant outside (-6.5 oC), liquid flask, 2.5 oC). “plasticized” amount CO2, function of the pressure CO2, which is read via a manometer. Rheo-cooling, in this case, consists opening valve CO2 to atmospheric pressure, “instantaneously” releases gas from top liquid, raises Tc solidification -3.5 oC 0 oC, i.e. above temperature 2.5 so that now, at each point liquid flask, should thermodynamically occur. In video, we observe wave front diffuses down very quickly, starting surface between and , as drops pressure. The initial state water before release was true can see video motion when technician raised flask outside refrigerant bath tilted it stood still. We clearly crystallization occurring everywhere all once throughout entire volume water. After about 5 seconds, ice has frozen solidified immobile translucent material, not transparent liquid. One also sees, during heat heats up material solidifying. final below 0, remained stable end. Note many parameters be changed cooling procedure: (used mixture ethylene glycol water, coil immerged bath), efficiency shaking method dissolve use vacuum jump-pump out trigger etc. summary, what did example show occur by raising value phase transition, here temperature. Normally, induced lowering actual across temperature, remains constant. There famous sequence film le Bossu” where chevalier Laguardere Jean Marais) warns his enemy saying :” Si tu ne vas pas Laguardere, ira toi”. Strangely enough, I always think of that sentence when I consider how to decrease (T-Tc), Tc being Laguardere and T the enemy. Solidification occurs they see each other fight T=Tc)!. Through this video illustrating concept Rheo-cooling works, one sees could be adapted situations, materials, making use parameters vary value phase transition, yet it may always considered as a new powerful way controlling state microstructure materials through simulation rates across transitions, providing effective rate values much beyond obtainable by conductive cooling. Suppose substantial enhancement property application rapid were possible, add degree freedom enhance effects. This especially interesting if technology applied bulky or thick materials. In particular, technique produce more homogeneous products after large thicknesses. Cooling transfer calories often does not yield high enough quench substantially modify physical behavior. With poor thermal conductors, such plastics, is impossible predict what kind improvements would result possible apply treatments.