Morphology‐Driven Sensitivity Enhancement of MEH‐PPV Langmuir‐Blodgett Films on Plastic Substrates for NO₂ Gas

Abstract

3D ordered Langmuir-Blodgett (LB) films of poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) were prepared via thermal annealing. Surface properties of MEH-PPV prepared by using different solvents, through both LB and Spin Casting techniques, were examined at the air-water interface by measuring surface pressure-area isotherms and Brewster Angle Microscopy. Dramatically different surface morphologies were obtained for spin cast and LB films, both prepared by using different solvents. The annealed LB films showed enhanced NO 2 gas sensing as compared to spin cast films. Spectroscopy and morphological analyses reveal that enhanced response of LB films toward NO 2 gas is due to their 3D ordered morphology, preferred molecular orientation for in-plane transport as well as higher surface area.

Effect of External Electric Field on Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(bithiophene)] Chain Orderness, Morphology, and Carrier Mobility in Different Condensation Processes

“…To a certain degree, regulating and controlling the molecular chain alignment through molecular engineering can greatly enhance device performance. Recently, a number of methods of optimizing the molecular chain alignment have been explored to construct efficient channels for carrier transport, such as solvent–vapor treatment, , rubbing aligned, , addition blending, , molecular interactions, , Langmuir–Blodgett film, , and nanoimprinting. , …”

Prominent processing techniques to manipulate semiconducting polymer microstructures

“…242 Under similar LB conditions, 3D ordered film microstructures comprising poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) chains oriented in-plane were fabricated on plastic substrates for sensing purposes. 243 Preparation of polymeric films with sensing properties was further targeted through the use of poly[(9,9-dioctylfluorene)- co -(3-hexylthiophene)] 244 and PANI. 245 In the latter case, Sharma and co-workers produced nanocomposites of PANI titanium oxide (TiO 2 ) comprising tiny TiO 2 particles well dispersed in the PANI-TiO 2 films, by controlling the compression and substrate lifting speeds, while keeping the surface pressure constant.…”