Integrated carboxylic carbon nanotube pathways with membranes for voltage-activated humidity detection and microclimate regulation

Abstract

This work describes some single walled carboxylic carbon nanotubes with outstanding transport properties when assembled in a 3D microarray working like a humidity membrane-sensor and an adjustable moisture regulator. Combined nano-assembly approaches are used to build up a better quality pathway through which assisted-charge and mass transport synchronically takes place. The structure-electrical response relationship is found, while controllable and tunable donor-acceptor interactions established at material interfaces are regarded as key factors for the accomplishment of charge transportation, enhanced electrical responses and adjustable moisture exchange. Raman and infrared spectroscopy provides indications about the fine structural and chemical features of the hybrid-composite membranes, resulting in perfect agreement with related morphology and electrical properties. Enhanced and modular electrical response to changes in the surrounding atmosphere is concerned with doping events, while assisted moisture regulation is discussed in relation to swelling and hopping actions. The electro-activated hybrid-composite membrane proposed in this work can be regarded as an attractive 'sense-to-act' precursor for smart long-distance monitoring systems with capability to adapt itself and provide local comfortable microenvironments.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes

“…It is unquestionable that changes in the hydrophilic-hydrophobic balance cause a competition between droplet nucleation and growth rate steps. Using other classes of amphiphilic compounds, changes in this balance are expected to further modify the time scale with consequences on the final texture of the polymeric porous film [ 13 ].…”

“…All this makes it attractive for the greener and time-saving design of well-architectured interfaces from several polymers. Indeed, this kind of honeycomb structure has been successfully proven to work as a highly breathable membrane when equipping membrane distillation plants [ 1 , 12 ] as well as porous platforms for the build-up of high-quality charge transfer pathways for humidity detection and regulation [ 13 ]. However, the commercial development of advanced devices based on materials with this long-range texture type necessarily requires a massive production.…”

Photoactive Gel for Assisted Cleaning during Olive Mill Wastewater Membrane Microfiltration

“…Hydrophilic polyethylene (PE) hollow fibers with pore size of 0.4 μm and internal/external diameters of 0.41/0.65 mm have been used to build up submerged configured MF modules (Econity, Yangji-myeon, South Korea). Titanium oxide nanoparticles (99%, Sigma Aldrich Srl, Milan, Italy) together with polyacrylic acid (PAA) (average M w = 250,000, Sigma Aldrich Srl, Milan, Italy) and poly(diallyldimethylammonium chloride) (PDDA) (average M w = 400,000–500,000, Sigma Aldrich Srl, Milan, Italy) solutions of 10 −2 M (based on repeat unit molecular weight) have been used to functionalize the shell side of each single hollow fiber according to the LBL method [ 21 , 22 ]. The nanoparticles have been dispersed in PAA solutions under ultrasound treatment for 24 h at a concentration of 0.5 mg mL −1 , while the pH of each solution has been adjusted to 6.75 by sodium hydroxide.…”

“…Precisely, titanium oxide (TiO 2 ) nanoparticles (NPs) have been dispersed in polyacrylic acid (PAA) and patterned with poly (diallyldimethyl ammonium chloride) (PDDA) in a hybrid complex that is deposited onto the shell side of polyethylene (PE) hollow-fiber membranes via layer-by-layer (LBL) approach [ 20 , 21 , 22 ]. Commercial PE membranes, which are considered tricky to manage wastewater due to the very high susceptibility to fouling, have been chosen with the intent to demonstrate the real efficiency of the photoactive gel under specific working conditions.…”

Effective Enhancement of Humidity Sensing Characteristics of Novel Thermally Treated MWCNTs/Polyvinylpyrrolidone Film Caused by Interfacial Effect

“…Carbon nanotubes (CNTs), 1D nanoscale material, are well‐known for their remarkable properties, such as excellent thermostability, large specific surface area, phenomenal mechanical strength, and electrical conductivity . Meanwhile, CNTs are generally used as humidity sensing materials in recent years . For instance, Jung et al fabricated a spin‐capable multi‐walled CNTs (MWCNTs) humidity sensor with a response‐recovery time above 20 s and the sensor exhibits unstability at high relative humidity (RH) .…”