# US 11,440,240 B2 · Methods and system for mass production, volume manufacturing of re-entrant structures

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- Number: US 11,440,240 B2
- Document ID: US11440240B2
- Status: Granted
- Kind: B2
- Application number: 16/667,414
- Filed: 2019-10-29
- Published: 2020-02-27
- Granted: 2022-09-13
- Earliest claimed: 2015-05-19
- Assignees: University of Massachusetts
- Applicants: The University of Massachusetts
- Inventors: Joey L. Mead; Carol M. F. Barry; John Shearer; Artee Panwar; Jinde Zhang; Nischay Kodihalli Shivaprakash
- Web page: https://patentgrep.com/patent/US11440240B2

## CPC

- B29C 59/022: {characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor}
- B29C 59/04: using rollers or endless belts
- G03F 7/0002: {Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping}
- B29C 2059/023: {Microembossing}
- B29K 2101/12: Thermoplastic materials
- B29K 2105/256: {Sheets, plates, blanks or films}
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

Methods and systems for manufacturing re-entrant structures, such as the structures exhibiting superomniphobic characteristic, in a continuous, well-controlled, high-rate (mass production, volume) manner are disclosed.

## Claims

### Claim 1

A system for mass production, volume manufacturing of reentrant structures, the system comprising:
a first and second rollers disposed with a gap between them; the gap dimensioned to surround an array of non-curable thermoplastic pillars protruding from a substrate and the substrate; relative rotation of the first and second rollers_being configured to draw the array and the substrate through the_gap;
at least one temperature adjusting component configured to_provide a temperature gradient from a surface of the non-curable thermoplastic pillars disposed farthest away from the substrate to a surface of the substrate; a temperature at the surface of the non-curable thermoplastic pillars disposed farthest away from the substrate being the temperature at which_a non-curable thermoplastic material of the non-curable thermoplastic pillars is substantially malleable; the temperature gradient being provided by heating a roller from the_first and second rollers, the roller being in contact with the surface of the non-curable thermoplastic pillars disposed farthest away from the substrate, to a first temperature while maintaining another roller from the first and second rollers, the another roller being in contact with the substrate, at a second temperature; a ratio between the first temperature and the second temperature being selected such that nonuniform flow_is produced in the non-curable thermoplastic material;
at least one pressure adjusting component configured to apply pressure on the surface of the non-curable thermoplastic_pillars disposed farthest away from the substrate; the pressure_and the temperature at the surface of the non-curable thermoplastic pillars disposed farthest away from the substrate selected to cause irreversible deformation of the non-curable_thermoplastic material; whereby the re-entrant structure is formed;
a driver component configured to drive rotation of the_first and second rollers; and
a system controller configured to control the driver component, the at least one pressure adjusting component and the_temperature adjusting component;
wherein the substrate is of a same_material as the array of non-curable thermoplastic pillars;
wherein the system further comprises:
an apparatus for forming as the array of non-curable_thermoplastic pillars, the apparatus comprising:
third and fourth rollers disposed with a gap between_them; the gap dimensioned to surround a sheet of_the non-curable thermoplastic material; relative rotation_of the first and second rollers being configured to draw_the sheet through the gap;
at least one other pressure adjusting component configured to provide a predetermined pressure between third and fourth rollers such that the sheet of the non-curable thermoplastic material is contact with the fourth_roller; wherein a flexible mold is disposed on the fourth_roller, the flexible mold having an array of apertures and_a predetermined thickness, wherein each aperture of the array of apertures has a diameter of 200 nm to 15 um, a height of 400 nm to 15 um, and a center to center spacing of 400 nm to 45 um; and
at least one other temperature adjusting component configured to heating at least the fourth roller such that_a surface of the sheet of the non-curable thermoplastic material is heated to a temperature at which nonuniform flow is produced; whereby the array of non-curable thermoplastic pillars is formed;
another driver component configured to drive rotation of the third and fourth rollers; and
wherein the system controller is also configured to control_the another driver component, the at least one other pressure adjusting component and the at least one other temperature adjusting component;
wherein the sheet of the non-curable thermoplastic material_is a flexible sheet disposed on a film roll and is configured to_be provided to the third and fourth rollers and the first and second rollers in a continuous matter such that continuous rollto-roll processing for forming the array of non-curable thermoplastic pillars and the re-entrant structures.

### Claim 2 (depends on 1)

The system of claim 1 wherein the apparatus for forming as_the array of non-curable thermoplastic pillars further comprises_a preheater component disposed between the film roll and the third and fourth rollers and configured to preheat a portion of_the sheet of the non-curable thermoplastic material to a predetermined temperature before moving through the gap; wherein_the system controller is also configured to control the preheating component.