Transfer printing using shape memory polymers
View Patent ↗A method of transfer printing comprises globally heating an array of stamps, where each stamp comprises a shape memory polymer with a light absorbing agent dispersed therein, and pressing the array of stamps to a donor substrate comprising a plurality of inks. Each stamp is thereby compressed from an undeformed adhesion-off configuration to a deformed adhesion-on configuration. The array of stamps is then cooled to rigidize the shape memory polymer and bind the plurality of inks to the stamps in the deformed adhesion-on configuration. The plurality of inks remain bound to the stamps while the array of stamps is positioned in proximity with a receiving substrate. A selected stamp in the array is then locally heated using a concentrated light source. The selected stamp returns to the undeformed adhesion-off configuration, and the ink bound to the selected stamp is released and transfer printed onto the receiving substrate.
1. A method of transfer printing on a receiving substrate, the method comprising:
globally heating an array of stamps, each stamp in the array comprising a shape memory polymer having a light absorbing agent dispersed therein;
pressing the array of stamps to a donor substrate comprising a plurality of inks, thereby compressing each stamp from an undeformed adhesion-off configuration to a deformed adhesion-on configuration;
cooling the array of stamps, thereby rigidizing the shape memory polymer and binding the plurality of inks to the stamps in the deformed adhesion-on configuration;
positioning the array of stamps in proximity with a receiving substrate, the plurality of inks remaining bound to the stamps during the positioning; and
after the positioning, locally heating a selected stamp in the array using a concentrated light source, the selected stamp returning to the undeformed adhesion-off configuration and the ink bound to the selected stamp being released and transfer printed onto the receiving substrate.
2. The method of claim 1 , wherein globally heating the array of stamps comprises heating the array to at least a glass transition T g of the shape memory polymer,
wherein cooling the array of stamps comprises cooling the array below the glass transition temperature T g of the shape memory polymer, and
wherein locally heating the selected stamp in the array comprises locally heating the selected stamp to at least the glass transition temperature T g of the shape memory polymer.
3. The method of claim 1 , wherein the concentrated light source comprises a laser, and wherein locally heating the selected stamp in the array comprises illuminating the selected stamp with near-infrared radiation.
4. The method of claim 1 , wherein light from the concentrated light source is absorbed by the light absorbing agent dispersed in the shape memory polymer, thereby effecting the local heating of the selected stamp, and wherein the selected stamp is locally heated to a temperature in a range from about 60° C. to about 120° C.
5. The method of claim 1 , wherein the stamps in the array other than the selected stamp remain in the deformed adhesion-on configuration during the local heating.
6. The method of claim 1 , further comprising rastering the concentrated light source to locally heat more than one stamp in the array, there being a plurality of the selected stamps.
7. The method of claim 1 , wherein the concentrated light source is disposed behind the array of stamps, the shape memory polymer being light-transmissive.
8. The method of claim 1 , wherein a spacing of the stamps in the array is at least as large as a spot size of the concentrated light source.
9. The method of claim 1 , wherein globally heating the array of stamps comprises resistive heating.
10. The method of claim 1 , wherein the inks comprise a material selected from the group consisting of: semiconductor, metal, carbon, colloid, organic material, and biological material, and
wherein the light absorbing agent is selected from the group consisting of: carbon black, carbon fibers, organic and inorganic absorption pigments, and dyes.
11. The method of claim 1 , wherein each stamp includes a plurality of raised surface features, and wherein the light absorbing agent is localized to the raised surface features.
12. A method of transfer printing on a receiving substrate, the method comprising:
globally heating an array of stamps, each stamp in the array comprising a shape memory polymer;
pressing the array of stamps to a donor substrate comprising a plurality of inks, thereby compressing each stamp from an undeformed adhesion-off configuration to a deformed adhesion-on configuration;
cooling the array of stamps, thereby rigidizing the shape memory polymer and binding the plurality of inks to the stamps in the deformed adhesion-on configuration;
positioning the array of stamps in proximity with a receiving substrate, the plurality of inks remaining bound to the stamps during the positioning; and
after the positioning, locally heating a selected stamp in the array, the selected stamp returning to the undeformed adhesion-off configuration and the ink bound to the selected stamp being released and transfer printed onto the receiving substrate.
13. The method of claim 12 , further comprising a light absorbing agent dispersed in the shape memory polymer, and
wherein locally heating the selected stamp in the array comprises irradiating the selected stamp with light from a concentrated light source, the light being absorbed by the light absorbing agent to effect the local heating.
14. The method of claim 12 , further comprising an addressable electrically conductive heating element in thermal contact with each of the stamps in the array, and
wherein locally heating the selected stamp in the array comprises passing a current through the respective electrically conductive heating element.
15. The method of claim 12 , wherein globally heating the array of stamps comprises resistive heating, radiant heating, or convective heating of the array.