Laboratory for Advanced Plastic Materials & Technology
College of Engineering & Science
Birthplace of Structured Materials, Polymer Blends and Composites Formed by Chaotic Advection
Smart blending header

  • Smart Blending / Chaotic Advection Blending
  • Nanocomposites and Polymer Blends
  • Functional Plastics, Plastic Films, Membranes, and Permeation Barriers
  • Chaotic Advection / Chaotic Mixing
  • Mixing Science and Technology
  • Computational Modeling of Multicomponent Flows
  • Heat and Mass Transfer
multilayer blend morphology
Multilayer Blend Morphology
Produced with a Smart Blender

3D chaotic mixer
3D Chaotic Mixer

Chaotic Advection Blender
for Extrusion

 News feature:

The Center for Layered Polymeric Systems (CLiPS) has been established at Case Western Reserve University, Cleveland, Ohio by the National Science Foundation. For more information, see News.

Current Highlights
smart blender extruding films
Smart blender in action!...A smart blender can be configured with a variety of dies to give extruded plastics with many types of morphologies or structural arrangements among solid additives in a desired net shape (i.e., film, pipe, tubing, sheet). In the photograph, a prototype smart blender is fitted with a film die where film is shown contacting a chill roll prior to winding. The film consists of two common thermoplastics arranged to impart property enhancement via morphology optimization. Structure-property optimization can be readily done since morphology can be controllably developed with smart blenders. For information on smart blending concepts, please see the tutorial.

Sub-micron layers formed by chaotic advection  

Controllable formation of submicron multiple layers: A new chaotic advection-based process has been developed where plastic extrusions of various forms (e.g, film, pipe, sheet, etc.) can be produced with a variety of blend morphologies in continuous lengths. Essentially, morphology is selectable on-line by control of chaotic advection and other parameters such that no equipment modifications are required.  In the micrograph, an example is shown of a novel blend that contains thousands of internal sub-micron layers (Zumbrunnen, D. A. and Inamdar, S., 'Novel Sub-Micron Highly Multi-layered Films Formed by Continuous Flow Chaotic Mixing,' Chemical Engineering Science, Vol. 56, pp. 3893-3897, 2001). The thicknesses and number of layers are selectable via control features in smart blending devices. Fibrous, interpenetrating, platelet, percolating, and droplet morphologies are examples of other blend morphologies that have been formed.  Various morphologies are obtained via sequential morphology transitions beginning with the layered morphology. Some morphology examples are given at the top of this page. (TOP)  For more recent examples, please see our publications.

nano drops      
Formation of very small droplets and other nano-scale shapes in polymer blends and viscous liquids:  A frequent goal is to produce very small droplets. Intensive mixing is commonly used in order to disperse and break up a viscous minor component.  However, with smart blending methods, the minor component is converted initially to very thin, numerous layers in the melt by chaotic advection. The layers break up to give droplets such as the 50 nanometer droplets shown in the micrograph to the left. Droplet size is correlated to the parent layer thickness so extremely small diameter droplets can be formed in polymer combinations where very thin layers can be created. Manufacturing processes that make use of this approach can have much reduced energy expenditures in comparison to current processing methods, such as compounding in a twin screw extruder. Also, a low shear condition allows use of melts that are prone to degradation. Methods can also be used to form other nano-scale structures in melts among solid additives or melt components for retention in extrusions of desired forms (e.g., sheet, film, pipe).  For more information, see: D. A.Zumbrunnen, S. Inamdar, O. Kwon, and P. Verma, "Chaotic Advection as a Means to Develop Nanoscale Structures in Viscous Melts," Nano Letters, Vol. 2, pp. 1143-1148, 2002.

Low permeation (high barrier) plastics: Kwon, O. and Zumbrunnen, D. A., "Production of Barrier Films by Chaotic Mixing of Plastics," Polymer Engineering & Science, Vol. 43, pp. 1443-1459, 2003. Abstract:  Recent studies have demonstrated that highly multilayered blend morphologies can be formed by chaotic mixing and captured within extrusions of various forms. The number and thickness of internal layers prior to layer breakup and the extent of breakup are controllable via specification of process variables. A variety of derivative morphologies can thereby be obtained. Although methods can be applicable to other blends, the relation of oxygen permeability to various morphologies was specifically investigated in this study for extruded films without stretching consisting of ethylene vinyl alcohol copolymer, low density polyethylene and maleic anhydride modified polyethylene as a compatibilizing agent. Optimal barrier properties were obtained in a novel single phase continuous and mechanically interlocked morphology that was an outcome of stretching and folding characterizing chaotic mixing. Barrier properties were similar to those obtainable in co-extruded films due the presence of abundant platelets across the film thickness and crystallinity increases caused by barrier phase refinement. (In the micrograph, an extruded film was immersed in liquid nitrogen and fractured to reveal thin platelets that were formed. Entire films contained numerous platelets and other high surface area shapes such as ribbons that were volumetrically distributed throughout the film thickness.  Because finer internal barrier structures can be formed in them, the potential is to produce barrier films that exceed the performance of co-extruded films.)

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Copyright © 1999-2008 Laboratory for Advanced Plastic Materials & Technology.  All rights reserved. Revised: April 10, 2008.
For inquiries or comments, contact:  Dr. David A. Zumbrunnen, Department of Mechanical Engineering, 221 Fluor Daniel Building, Clemson University, Clemson, SC  29634-0921. (tel. 864-656-5625,  e-mail: ) .