1
|
Torun I, Huang C, Kiremitler NB, Kalay M, Shim M, Onses MS. Coffee-Ring Mediated Thinning and Thickness-Dependent Dewetting Modes in Printed Polymer Droplets Coupled with Assembly of Quantum Dots for Anti-Counterfeiting. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2405429. [PMID: 39077934 DOI: 10.1002/smll.202405429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Indexed: 07/31/2024]
Abstract
Molecular transport processes in printed polymer droplets hold enormous importance for understanding wetting phenomena and designing systems in applications such as encoding, electronics, photonics, and sensing. This paper studies thickness-dependent dewetting modes that are activated by thermal annealing and driven by interfacial interactions within microscopically confined polymeric features. The printing of poly(2-vinylpyridine) is performed in a regime where coffee-ring effects lead to strong thinning of the central region of the deposit. Thermal annealing leads to two different modes of dewetting that depend on the thickness of the central region. Mode I refers to the formation of randomly positioned small features surrounded by large hemispherical ones located along the periphery of the printed features and occurs when the central regions are thin. Observed at large central thicknesses, Mode II mediates significant molecular transport from edges toward the center of the printed droplet with thermal annealing and forms a hemispherical feature from the initial ring-like deposit. The selective adsorption of red, green, and blue emitting quantum dots over the poly(2-vinylpyridine) results in photoluminescent patterns. The selective assembly of photoluminescent quantum dots over patterned surfaces leads to deterministic and stochastic features beneficial to creating security labels for anti-counterfeiting applications.
Collapse
Affiliation(s)
- Ilker Torun
- Department of Materials Science and Engineering, Erciyes University, Kayseri, 38039, Turkey
- ERNAM - Nanotechnology Application and Research Center, Erciyes University, Kayseri, 38039, Turkey
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Conan Huang
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - N Burak Kiremitler
- Department of Materials Science and Engineering, Erciyes University, Kayseri, 38039, Turkey
- ERNAM - Nanotechnology Application and Research Center, Erciyes University, Kayseri, 38039, Turkey
| | - Mustafa Kalay
- Department of Electricity and Energy, Kayseri University, Kayseri, 38039, Turkey
| | - Moonsub Shim
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Mustafa Serdar Onses
- Department of Materials Science and Engineering, Erciyes University, Kayseri, 38039, Turkey
- ERNAM - Nanotechnology Application and Research Center, Erciyes University, Kayseri, 38039, Turkey
| |
Collapse
|
2
|
Using intrinsic properties of quantum dots to provide additional security when uniquely identifying devices. Sci Rep 2022; 12:16919. [PMID: 36209282 PMCID: PMC9547896 DOI: 10.1038/s41598-022-20596-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/15/2022] [Indexed: 12/29/2022] Open
Abstract
Unique identification of optical devices is important for anti-counterfeiting. Physical unclonable functions (PUFs), which use random physical characteristics for authentication, are advantageous over existing optical solutions, such as holograms, due to the inherent asymmetry in their fabrication and reproduction complexity. However, whilst unique, PUFs are potentially vulnerable to replication and simulation. Here we introduce an additional benefit of a small modification to an established model of nanoparticle PUFs by using a second measurement parameter to verify their authenticity. A randomly deposited array of quantum dots is encapsulated in a transparent polymer, forming a tag. Photoluminescence is measured as a function of excitation power to assess uniqueness as well as the intrinsic nonlinear response of the quantum material. This captures a fingerprint, which is non-trivial to clone or simulate. To demonstrate this concept practically, we show that these tags can be read using an unmodified smartphone, with its built-in flash for excitation. This development over constellation-style optical PUFs paves the way for more secure, facile authentication of devices without requiring complex fabrication or characterisation techniques.
Collapse
|