Reactive Surface Coatings Based on Polysilsesquioxanes: Universal Method toward Light-Responsive Surfaces

Abstract

Reactive surface coatings were used as an ideal precursor coating for the fabrication of three different photoswitchable surface coatings in parallel. Different light-responsive moieties, such as azobenzene, salicylideneaniline, and spiropyran, were immobilized on glass, polycarbonate, and steel surfaces. Independent from the underlying substrate, wettability could be switched reversibly by UV irradiation. The maximum switching range was obtained after functionalization of the reactive coating with spiropyran, resulting in a contact angle difference between the two isomeric states of almost 30°.

Fabrication of Chemically Tunable, Hierarchically Branched Polymeric Nanostructures by Multi-branched Anodic Aluminum Oxide Templates

“…For example, the static CA of free-standing spiropyran-modified nanopillars decreased In comparison to previous studies on the spiropyranmodified thin films, the changes of CAs before and after UV irradiation are smaller but appear around the CA of 90°; hence, it is assumed that the roughness of structures, which generate the hydrophobic surface, offsets the effect of the photoisomerization of spiropyran. 48 Even though the changes were smaller, all of hierarchically branched structures showed the decrease of CAs after UV irradiation. In addition, the CAs were reversibly switchable upon UV irradiation, followed by thermal relaxation (see section S8 of the Supporting Information).…”

Liquid crystalline side-chain triblock copolymers consisting of a nematic central subblock edged by photochromic azobenzene-containing fragments: their synthesis, structure and photooptical behaviour

“…66 The polymerization in this case proceeded relatively rapid: the limited conversions were reached during 2 h of heating at 80 o C. However the PDI value slightly increased in the course of the polymerization, which in conditions of hundredfold molar excess of RAFT agent to initiator might be caused by the side reaction of the substituted amino group of monomer and the propagating radical. 67 The fact that PDI remains much lower than that of the polymers synthesized via conventional free radical 4 1.55 8 6 0.9 80 70 pA 10 -b-pPhM 80 -b-pA 10 1.52 20 19 0.8 80 80 pA 7 -ran-pPhM 30 1.35 7 9 0.8 30 40 pAzo 20 1.39 20 19 0 0 0 pAzo 4 -b-pPhM 80 -b-pAzo 4 1.55 8 6 0.9 80 70 pAzo 10 -b-pPhM 80 -b-pAzo 10 1.52 20 19 0.8 80 80 pAzo 7 -ran-pPhM 30 1.41 7 9 0.8 30 40 Please do not adjust margins Please do not adjust margins protons owing to replacement of protons situated in the paraposition with respect to the amino group with an azo group during modification. Moreover, the chemical shift of protons located in the meta-position with respect to the amino group changes from ~7.1 ppm to ~7.7 ppm.…”

“…microphoto 20 75 SmA 155 (2.2) I pA 4 -b-pPhM 80 -b-pA 4 29 N 119 (0.8) I pA 10 -b-pPhM 80 -b-pA 10 -1/28 N 122 (0.9) I pAzo 4 -b-pPhM 80 -b-pAzo 4 33 N 122 (0.9)I pAzo 10 -b-pPhM 80 -b-pAzo 10 33 LC 136 (1.4) I pA 7 -ran-pPhM 30 21 N 75 (0.7) I pAzo 7 -ran-pPhM 30 37 N 108 (0.7) I a Subscripts indicate the polymerization degree of subblocks. b Mesophases: N is the nematic phase, SmA is the smectic phase A, and I is the isotropic melt.…”

“…Liquid crystalline (LC) azobenzene-containing polymers belong to such materials capable of providing a fast response to the light action through a reversible photoinduced E-Z isomerization of azobenzene (Azo) chromophore accompanied by large changes occuring of its molecular size, shape, and polarity [1][2][3] . These structural changes may essentially influence on wettability, 4,5 phase transitions, [6][7][8][9] thin films contracting, [10][11][12][13][14][15][16][17] and surface modification [18][19][20] of polymers. Under irradiation by linearly polarized light the Azo chromophores are known to orient preferentially in the direction perpendicular to the polarization plane of the excitation light (Weigert effect 21 ).…”

Preparation of dual stimuli-responsive block copolymers based on different activated esters with distinct reactivities

“…The straightforward way to prepare functional polymers is the direct polymerization of the respective functional monomer. However, in some cases functional monomers are incompatible with the available polymerization technique or inhibit a precise characterization [4] [5]. In such cases, the polymerization of reactive polymer precursors, followed by a post-polymerization modification step provides an alternative approach for the synthesis of functional polymeric materials.…”