Influence of supramolecular interactions on photoresponsive behavior of azobenzene poly(amide imide)s

Poly(amic acid)s and their poly(amide imide) counterparts containing azobenzene moieties: Characterization, imidization kinetics and photochromic properties

“…Thus, taking the above into account it can be suspected that both of the chromophores (i.e., also the AKFNO 2 one) present in the repeating unit of PI-2 and PI-3 isomerize and reorient under the linearly polarized writing beams. Large birefringence generated by light in PI-2 and PI-3 confirms the necessity of the presence of azobenzene derivative between the amide linkages for efficient photoorientation, what is our recent observation [23]. Present results show that the birefringence values as large as in poly(amide imide) s may be also achieved in poly(amic acid)s.…”

Photoresponsive polymers with multi-azobenzene groups

“…135 Additionally, other studies based on hydrogen-bonded polymers with supramolecular multi-azobenzene groups in parallel have been reported. Photoinduced anisotropy, 136 orientation, 136,137 or birefringence 136,137 and the photoinduced deformation 138 of these supramolecular multi-azopolymers have been investigated.…”

Azobenzene Functionalized “T-Type” Poly(Amide Imide)s vs. Guest-Host Systems—A Comparative Study of Structure-Property Relations

“…Our previous works showed that poly(amide imide)s with two azobenzene moieties per structural unit exhibited the highest and the most stable photoinduced birefringence, as was observed for polyimides [33]. On the other hand, poly(amide imide)s with phenyl rings in the main-chain and azobenzene between the imide structure did not exhibit birefringence, because of the forming intermolecular hydrogen bonds; in addition, poly(amide imide)s with chromophores between amide linkages were insoluble in organic solvents [34,35]. The unexpected results for PIs with one azo group in the polymer-repeating unit made it impossible to research the influence of a location of an azo dye (between imide or amide linkages) on the physicochemical properties, including the photoinduced birefringence.…”

“…In this paper, two series of "T-type" azo polyimides i.e., functionalized and guest-host azo systems (Figure 1) are described. Functionalized poly(amide imide)s PAI-5-PAI-8 and doped azo system PAI-9[Az(CH 3 )] were synthesized and characterized in our previous works [33][34][35][36][37]. Polyimides with pyridine rings in the polymer backbone are new materials.…”

“…We proved that poly(amide imide)s containing covalently bonded azobenzene between imide rings (PAI-5 and PAI-6) and without side azo groups readily formed the intermolecular hydrogen bonds between amide linkages [34,36]. The formation of the intermolecular H-bonds by polymers significantly influenced their physical properties i.e., led to poor solubility in organic solvents, generated a large blue shift of the absorption maximum, or hampered the photoinduced birefringence [34,36].…”