Environmentally responsive optical microstructured hybrid actuator assemblies and applications thereof

Abstract

Microstructured hybrid actuator assemblies in which microactuators carrying designed surface properties to be revealed upon actuation are embedded in a layer of responsive materials. The microactuators in a microactuator array reversibly change their configuration in response to a change in the environment without requiring an external power source to switch their optical properties.

1 - 20 . (canceled) 
     
     
         21 . An apparatus comprising:
 a substrate with a surface;   an environmentally responsive hydrogel polymer layer disposed on a region of the surface; and   a plurality of microactuators embedded in the environmentally responsive hydrogel polymer layer,   microactuators of the plurality of microactuators configured to move from a first position to a second position, in response to a volume change of the environmentally responsive hydrogel polymer layer from a first volume to a second volume, such that the movement of the microactuators alters an optical property of the apparatus, and   
       the volume change of the environmentally responsive hydrogel polymer layer controlled by a stimulus including at least one of a chemical species concentration change or an ion concentration change. 
     
     
         22 . The apparatus of  claim 21 , wherein the microactuators are configured to deform in response to the volume change. 
     
     
         23 . The apparatus of  claim 22 , wherein the microactuators are configured to bend in response to the volume change. 
     
     
         24 . The apparatus of  claim 22 , wherein the microactuators are configured to twist or buckle in response to the volume change. 
     
     
         25 . The apparatus of  claim 22 , wherein the microactuators are configured to tilt in response to the volume change. 
     
     
         26 . The apparatus of  claim 21 , wherein the microactuators are cylindrical objects that are fully embedded or partially embedded in the hydrogel layer. 
     
     
         27 . The apparatus of  claim 21 , wherein the plurality of microactuators is an array of deformable geometrical features including posts, blades, cones, pyramids or inverted cones embedded fully or partially in the hydrogel layer. 
     
     
         28 . The apparatus of  claim 21 , wherein each microactuator of the plurality of microactuators has a cross-sectional shape, defined in a plane parallel to the surface of the substrate, that is circular, square, oval, rectangular or irregular. 
     
     
         29 . The apparatus of  claim 21 , wherein each microactuator of the plurality of microactuators has a cross-sectional shape, defined in a plane parallel to the surface of the substrate, that is a combination of at least two of: circular, square, oval, rectangular and irregular. 
     
     
         30 . The apparatus of  claim 21 , wherein each microactuator of the plurality of microactuators has a cross-sectional shape, defined in a plane parallel to the surface of the substrate, that is symmetric or asymmetric. 
     
     
         31 . The apparatus of  claim 21 , wherein each microactuator of the plurality of microactuators has an undulated sidewall. 
     
     
         32 . The apparatus of  claim 31 , wherein the undulated sidewall comprises a periodic pattern. 
     
     
         33 . The apparatus of  claim 21 , wherein each microactuator of the plurality of microactuators has a cross-sectional shape, defined in a plane normal to the surface of the substrate, that is step-wise or continuous gradient along an axis extending from the surface of the substrate to a distal end of the corresponding microactuator. 
     
     
         34 . The apparatus of  claim 21 , wherein the plurality of microactuators is arranged in a periodic array. 
     
     
         35 . The apparatus of  claim 21 , wherein the microactuators are cylindrical objects with undulated sidewalls, the microactuators fully embedded or partially embedded in the hydrogel layer. 
     
     
         36 . The apparatus of  claim 21 , wherein a first end of each microactuator is in direct contact with the surface. 
     
     
         37 . The apparatus of  claim 21 , wherein a first end of one or more microactuators is spaced apart from the surface. 
     
     
         38 . The apparatus of  claim 21 , wherein a first end of one or more of the microactuators is attached to the surface. 
     
     
         39 . The apparatus of  claim 21 , wherein different portions of the environmentally responsive hydrogel polymer layer are responsive to different stimuli or to a different combination of stimuli. 
     
     
         40 . The apparatus of  claim 21 , wherein the microactuators are embedded in the environmentally responsive hydrogel polymer layer in a plurality of microarray patterns. 
     
     
         41 . The apparatus of  claim 21 , wherein the plurality of microactuators displays a pattern upon actuation. 
     
     
         42 . The apparatus of  claim 21 , wherein the microactuators have a dimension perpendicular to the surface in a range of 1 μm to about 1 mm. 
     
     
         43 . The apparatus of  claim 21 , wherein the microactuators have a cross-sectional thickness in a range of 10 nm to about 1,000 μm. 
     
     
         44 . An apparatus comprising:
 a substrate with a surface;   an environmentally responsive hydrogel polymer layer disposed on the surface;   a first group of microactuators at least partially embedded in a first region of the environmentally responsive hydrogel polymer layer; and   a second group of microactuators at least partially embedded in a second region of the environmentally responsive hydrogel polymer layer,   microactuators of the first group of microactuators configured to move from a first position to a second position, in response to a volume change of the first region of the environmentally responsive hydrogel polymer layer from a first volume to a second volume, such that the movement of the microactuators of the first group of microactuators alters a first optical property of the apparatus,   microactuators of the second group of microactuators configured to move from a first position to a second position, in response to a volume change of the second region of the environmentally responsive hydrogel polymer layer from a first volume to a second volume, such that the movement of the microactuators of the second group of microactuators alters a second optical property of the apparatus,   the volume change of the first region of the environmentally responsive hydrogel polymer layer controlled by a first stimulus, and   the volume change of the second region of the environmentally responsive hydrogel polymer layer controlled by a second stimulus.   
     
     
         45 . The apparatus of  claim 44 , wherein the first stimulus and/or the second stimulus includes at least one of: a pH change, a chemical species concentration change, or an ion concentration change. 
     
     
         46 . The apparatus of  claim 44 , wherein the first stimulus includes a first chemical species concentration change, and the second stimulus includes a second chemical species concentration change that differs from the first chemical species concentration change. 
     
     
         47 . The apparatus of  claim 44 , wherein the microactuators of the first group of microactuators and/or the microactuators of the second group of microactuators have a dimension perpendicular to the surface in a range of 1 μm to about 1 mm. 
     
     
         48 . The apparatus of  claim 44 , wherein the microactuators of the first group of microactuators and/or the microactuators of the second group have a cross-sectional thickness in a range of 10 nm to about 1,000 μm. 
     
     
         49 . An apparatus comprising:
 a substrate with a surface;   an environmentally responsive hydrogel polymer layer disposed on the surface;   a first group of microactuators at least partially embedded in a first region of the environmentally responsive hydrogel polymer layer; and   a second group of microactuators at least partially embedded in a second region of the environmentally responsive hydrogel polymer layer,   microactuators of the first group of microactuators configured to move from a first position to a second position, in response to a volume change of the first region of the environmentally responsive hydrogel polymer layer from a first volume to a second volume, such that the movement of the microactuators of the first group of microactuators alters a first optical property of the apparatus,   microactuators of the second group of microactuators configured to move from a first position to a second position, in response to a volume change of the second region of the environmentally responsive hydrogel polymer layer from a first volume to a second volume, such that the movement of the microactuators of the second group of microactuators alters a second optical property of the apparatus, and   the volume change of the first region of the environmentally responsive hydrogel polymer layer controlled by a stimulus.   
     
     
         50 . An apparatus comprising:
 a substrate with a surface; and   a plurality of microactuators disposed on the surface,   microactuators of the plurality of microactuators comprising an environmentally responsive material,   the microactuators configured to move from a first configuration to a second configuration in response to a stimulus, such that the movement of the microactuators alters an optical property of the apparatus,   the stimulus including at least one of a chemical species concentration change or an ion concentration change.