Nonvolatile, Multicolored Photothermal Writing of Block Copolymer Structural Color

Abstract

In spite of efforts to fabricate stimuli-sensitive structural colors (SCs) of self-assembled block copolymer (BCP) photonic crystals (PCs) with potential applications in displays, media boards, and sensors, few studies have demonstrated BCP PCs suitable for high-density nonvolatile information storage. Herein, a simple but robust route for multilevel nonvolatile information recording using a BCP PC is presented. The proposed method is based on the spatially controlled crosslinking of microdomains of a BCP PC induced by photothermal conversion. Photothermal SC writing is accomplished via time-and position-controlled laser exposure on thin poly(styrene-blockquaternized 2-vinyl pyridine) (PS-b-QP2VP) PC films deposited on a layer of poly(3,4-ethylenedioxythiophene) doped with tosylate (PP-PEDOT). Upon near-infrared (NIR) irradiation of this structure, the PP-PEDOT underlayer converts the NIR light into thermal energy in the locally irradiated region, which is subsequently transferred to the BCP top layer consisting of alternating in-plane PS and QP2VP lamellar stacks. The QP2VP layers are vulnerable to thermal crosslinking, giving rise to locally programmable SCs. The degree of crosslinking of the QP2VP domains depends on the laser power and exposure time, which allows for multi-SC recording per spot, leading to a novel multilevel optical recording medium based on BCP PCs.

Nanophotonic Structural Colors

“…78 Another interesting application is colorimetric sensing. [194][195][196][197][198][199][200][201] Structural color elements can be designed such that they visually respond to different external stimuli such as temperature, chemicals, and humidity through the use of suitable materials in an optically resonant system. [202][203][204][205][206][207][208][209][210][211][212][213] The benefit of colorimetric sensing is in realizing passive devices that are untethered to an energy source.…”

Recent Advances in Block Copolymer Self‐Assembly for the Fabrication of Photonic Films and Pigments

“…Recently, Kang et al found that radicals can be generated in QP2VP domains by heating, which can directly crosslink the QP2VP polymer chains. [115] By varying the amounts of quaternization and crosslinking agents used, different degrees of crosslinking were achieved across a range of temperatures. To induce crosslinking in more precise and localized areas, heating was realized via photothermal conversion using poly(3,4-ethyl-enedioxythiophene) doped with tosylate (PP-PEDOT) (Figure 7a).…”

Thermo‐Adaptive Block Copolymer Structural Color Electronics

“…In order to develop such a thermo‐responsive PC, we employed a PC based on a thin BCP film with self‐assembled periodic structures readily and precisely tunable upon a variety of external stimuli such as solvent, [ 25,26 ] strain, [ 27 ] electric field, [ 28 ] and photothermal energy. [ 29 ]…”