A team at the Massachusetts Institute of Technology (MIT) has developed a way to make soft materials using a 3D printer so that surface textures can be modified at will to be smooth, bumpy or even to have complex patterns that could guide fluids.

How embedded hard particles within a softer flexible material produce a textured surface when compressed. Source: MIT, Credit: Mark GuttagHow embedded hard particles within a softer flexible material produce a textured surface when compressed. Source: MIT, Credit: Mark GuttagThe process, developed using computer simulations, involves a material that is composed of two different polymers with different degrees of stiffness—particles with greater rigidity are embedded within a matrix of a more flexible polymer. When squeezed, the material’s surface changes from smooth to a pattern determined by the spacing and shapes of the implanted rigid particles. When released, the material reverts to its original form.

The findings are reported in the journal Advanced Functional Materials.

The system can produce simple, repetitive patterns of bumps or creases, which could be useful for changing an object’s aerodynamic resistance or its reflectivity. It also could be used to produce complex surface textures—for example, to control the movement of liquids inside a chemical or biological detector.

Surface textures can be important in a variety of applications, including camouflage, surfaces that repel or attract water, controlling the motion and turbulence of fluids and limiting the buildup of organisms on surfaces such as ship hulls.

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