In situ UV–vis absorbance measurements for Langmuir films of poly[4′-[[2-(methacryloyloxy)-ethyl]ethylamino]-2-chloro-4-nitroazobenzene] (HPDR13) azopolymer

Interaction between cholesterol and chitosan in Langmuir monolayers

“…The chitosan samples were dissolved in the same buffer solutions using concentrations between 0.050 mg/mL and 0.300 mg/mL. Brewster angle microscopy (BAM) images were obtained with a BAM2 system from Nanof ilm Technology (Germany), according to the experimental procedures described in reference [17] .…”

Molecular organization and doping in poly(2-methoxyaniline)/Ni(dmit)2 films obtained with the Langmuir–Blodgett technique

“…Poly(2-methoxyaniline) was obtained from the oxidative polymerization of o-anisidine (Sigma-Aldrich, USA) using 1 mol L 21 HCl solution and ammonium persulfate as oxidant. The polymer was obtained in the conducting emeraldine salt form and transformed into emeraldine base (EB) after treatment with 0.1 mol L 21 NH 4 OH solution for 24 h. The dark blue solid EB obtained was filtered, washed and dried under dynamic vacuum.…”

“…The spectroscopic characterization with FTIR and UV-Vis absorption confirmed that POMA was obtained. The main IR bands of a KBr pellet with POMA appeared at 1207 cm 21 (stretching of secondary aromatic amine), 1260 and 1029 (C-O-C stretching of alkyl aryl ether linkage), 1460 (C-H bending of the -OCH 3 group), 1494 (CLC stretching of the benzenoid rings) and 1600 (CLC stretching of the quinoid rings). 19 In the UV-Vis spectrum bands were observed at 330 nm, assigned to the p-p* transition in 1-methyl-2-pyrrolidone, and at 635 nm, assigned to the benzenoid to quinoid transition.…”

“…Chloroform solutions of [Ni(dmit) 2 ](CTAB) 2 , POMA and POMA/[Ni(dmit) 2 ](CTAB) 2 mixtures with five molar propor-tions (indicated in the results section) were prepared at 0.75 mg mL 21 . A KSV5000 trough (total volume of 1250 mL) placed in a class 10 000 clean room was used for surface pressure-area (p-A) isotherm measurements.…”

“…Solutions were spread over the subphase containing ultrapure water supplied by a Millipore system, with resistivity # 18.2 MV cm, pH # 5.5-6.0, surface tension # 72.5 mN m 21 . Aliquots of these solutions were spread carefully drop by drop on the surface of the aqueous subphase, after which the solvent was allowed to evaporate over 10-15 min before starting film compression with two movable barriers at a rate of 10 mm min 21 . Surface pressure (p) was measured during film compression using a Wilhelmy plate.…”