Reversible Photo-Induced Reshaping of Imprinted Microstructures Using a Low Molecular Azo Dye

Abstract

A blend of low molecular azo glass (AZOPD) and polystyrene (PS) were used for the systematic investigation of photo-induced stretching and recovery of nanoimprinted structures. For this purpose, light and heat was used as recovery stimuli. The AZOPD/PS microstructures, fabricated with thermal nanoimprint lithography (tNIL), comprises three different shapes (circles, crosses and squares) and various concentrations of AZOPD fractions. The results show a concentration-dependent reshaping. Particularly the sample with 43 w-% of the AZOPD fraction have shown the best controllable recovery for the used parameters. A possible explanation for shape recovery might be the stabilizing effect of the PS-matrix.

Two-Dimensional Polarization Holographic Gratings in Azopolymer Thin Films: Polarization Properties in the Presence or Absence of Surface Relief

“…Additionally, more complex, two-dimensional surface relief structures realized in azo materials have also been reported [17][18][19][20][21][22]. Yi et al [17] show how controlling the relief height in the created two-dimensional structures can affect the formation of 3D patterns of colloids on the symmetrically and asymmetrically patterned 2D SRG substrates.…”

“…Due to the short wavelength of the recording laser, gratings with a period on the order of 200 nm were obtained. The ability to reversibly generate relief structures is the main topic of research in [22]. Linearly polarized light or heat were successfully used as the stimuli for the reversible reshaping of periodic structures, imprinted in a blend of low-molecular azo glass and polystyrene.…”

Polarization properties of two-dimensional polarization holographic gratings inscribed in azopolymer thin films

“…Controlling the process of formation of nano and micro relief structures enables many applications in the fields of photonics, photoelectrochemistry, optical communications, data storage, etc. Most of the studies are focused on 1D [4,[9][10][11][12][13] and rarely on 2D gratings [5,14]. Also, well-ordered 2D nanoscale structures have been engineered mainly by costly and time consuming processes as e-beam lithography, and scanning probe methods.…”

“…Also, well-ordered 2D nanoscale structures have been engineered mainly by costly and time consuming processes as e-beam lithography, and scanning probe methods. In contrast, SRG offer as a simple, cheap, low energy, one-step fabrication of various nanoscale structures [9][10][11][12][13][14]. Additional advantage of the SRG structures inscribed in azopolymers is that they are reversible and can be reshaped optically [13].…”

“…In contrast, SRG offer as a simple, cheap, low energy, one-step fabrication of various nanoscale structures [9][10][11][12][13][14]. Additional advantage of the SRG structures inscribed in azopolymers is that they are reversible and can be reshaped optically [13]. The authors in [14] investigate how the rotational angle between the two-steps of writing can influence the depth of the surface relief of the 2D SRG.…”