In-situ atomic force microscopy study of the mechanism of surface relief grating formation in photosensitive polymer films

Abstract

When photosensitive azobenzene-containing polymer films are irradiated with light interference patterns, topographic variations in the film develop that follow the local distribution of the electric field vector. The exact correspondence of e.g., the vector orientation in relation to the presence of local topographic minima or maxima is in general difficult to determine. Here, we report on a systematic procedure how this can be accomplished. For this, we devise a new set-up combining an atomic force microscope and two-beam interferometry. With this set-up, it is possible to track the topography change in-situ, while at the same time changing polarization and phase of the impinging interference pattern. This is the first time that an absolute correspondence between the local distribution of electric field vectors and the local topography of the relief grating could be established exhaustively. Our setup does not require a complex mathematical post-processing and its simplicity renders it interesting for characterizing photosensitive polymer films in general.

Photo-Physical Transformations in Pyrazoline Derivative Based Systems

“…[1][2][3][4] Azobenzene derivatives have been used as photoalignment molecules for liquid crystals [5][6][7][8] , optical memories [9][10][11][12][13][14][15] and when embedded in polymers for recording of polarization and surface relief gratings. [16][17][18][19][20][21][22] The reason of their exceptionally wide usage was linked with the molecular configurational trans-to-cis transition leading to the several opto-mechanical effects. [23][24][25][26] When azobenzene derivatives are attached to the polymer main chains they exhibit the Weigert effect 27 which describes the light induced molecular orientation of the transstate azobenzene molecules with their long molecular axes set perpendicularly to the plane of linearly polarized light incident on the polymer film.…”

Confocal Raman Microscopy and AFM Study of the Interface Between the Photosensitive Polymer Layer and Multilayer Graphene

“…In order to follow the kinetic of the SRG inscription in-situ, a home-made set up combining optical part for generation of interference pattern and an AFM was applied. 26,27,35 The The experimental details of the Raman microscope and measurements of polymer surface relief gratings have been described elsewhere. 28 Here we describe in details experimental conditions related to the multilayer-graphene flakes (ML-graphene).…”

Laser inscription of surface structures and induction of optical anisotropy in azo-benzene substituted photochromic polymers and other systems

“…optical data storage, light processing, photomechanics and photofluidics stimulates development of novel materials and tools for material modifications. Photochromic materials, such as azo-functionalized polymers have been widely investigated [1][2][3][4][5] because of their unique features to undergo inducement of optical anisotropy and surface mass transport upon suitable laser light irradiation [6][7][8][9][10][11]. Recently it has been demonstrated that the chiral symmetry of light (angular momentum of photons in the beam) can be mapped via mass transport and surface pattern formation in azo-polymers [11].…”