Fabrication of metamaterial absorber using polymer brush – gold nanoassemblies for visualizing the reversible pH-responsiveness

Abstract

Poly(2-dimethylaminoethyl methacrylate) was grafted onto flat silicon substrates via atom transfer radical polymerization to form bottom layers. Two fabrication processes, very-large-scale integration and reactive ion etching, were applied in sequence to generate 400 nm-scale hole arrays of tethered poly(2dimethylaminoethyl methacrylate) layers as sub-wavelength hole array on the Si surfaces, followed by the immobilization of surface functionalized gold nanoparticles by means of physical interaction (electrostatic attraction, entanglement, and hydrogen bonding) to generate a metamaterial absorber.Hole dimensions of the metamaterial absorber shrank reversibly and significantly upon changing the pH from 10.7 and 3.3 due to swelling behavior, leading to a significant change in surface plasmon resonance. We found that the change in the surface plasmon resonance of the metamaterial absorber, related to the dimensions of its holes upon pH treatment, resulted in a color change from purple to orange, observable by the naked eye at a fixed angle of 10 . The maximum shift of the absorptive peak position was greater than 300 nm, and these shifts corresponded to the color changes in the solutions at various values of pH.

Broadening the absorption bandwidth of metamaterial absorbers by transverse magnetic harmonics of 210 mode

“…Metamaterials possess exotic electromagnetic properties, and have important applications in diverse areas, such as sensors 1 2 3 , invisibility cloaks 4 5 6 , camouflage 7 8 and energy harvesting 9 10 11 . Among them, metamaterial absorbers (MMAs) have attracted considerable attention from radio to optical frequency by virtue of the perfect absorption, thin thickness and flexible design ability of the metamaterials 9 10 11 12 13 14 .…”

Coordination between Surface Lattice Resonances of Poly(glycidyl Methacrylate) Line Array and Surface Plasmon Resonances of CdS Quantum on Silicon Surface

“…The grating absorber, which is a special resonant electromagnetic wave absorber, used a reflective plane with an etched shallow periodic grid [50]. The periodic grid and incident radiation interactions created resonance, which in turn produced a period of anomalous diffraction [8]. The effect changes in the grating period and grating ridge width on the absorptance spectra of the PGMA grating, as shown Figure 4b, indicate that with a constant grating height, there is an increment in the grating ridge in the order of 2.1 µm to 4.4 µm, without any virtual changes in the value of peak absorptance and FWHM.…”

“…The fabrication of well-defined chemically patterned surfaces at the micro- and nanoscale is at the heart of many modern scientific and technical fields. To date, there are several well-patterned polymer brushes with specific control levels over the polymer brush composition and thickness, and patterns have been fabricated by semiconductor process methods such as photolithography [5,6], plasma etching [7,8], reversible addition-fragmentation chain transfer polymerization (RAFT) [9,10] and atom transfer radical polymerization (ATRP) [11,12,13,14]. The use of polymers as building blocks for surface modification gives rise to the preparation of “smart” or responsive surfaces based on conformational changes in the polymer backbones.…”

“…Stable polymer brushes can provide excellent mechanical and chemical protection to substrates, alter the electrochemical characteristics of the interface, and provide new pathways for functionalization of silicon surfaces. [8,15]. One particular advantage that polymer brushes have over spin-coated polymer layers is their stability against solvents or harsh conditions (e.g., high temperatures) because they are bonded covalently to the substrates.…”

Preparation of Homopolymer, Block Copolymer, and Patterned Brushes Bearing Thiophene and Acetylene Groups Using Microliter Volumes of Reaction Mixtures

“…Moreover, recent progress in SI-RDRPs resulted in the development of photoinduced SI-ATRP, which may not only use low concentrations of metal-based catalyst [11,12] but also enables polymer brush synthesis using microliter volumes of reaction Polymers 2021, 13, 4458 2 of 16 mixture [13]. Photoinduced SI-ATRP is a very convenient method for the production of patterned brushes [11,14] that are commonly produced by complex techniques, such as electron-beam [15] and dip-pen lithography [16,17], a combination of photolithography and etching [18,19], or microcontact printing [20]. It is worth emphasizing that patterned brushes or polymer films are of great interest due to their potential applications, such as platforms for the selective adsorption of biomolecules, cell culture substrates, sensors, information storage devices, or nano/microelectronics [21,22].…”