Attachment of humidity-sensitive membranes to electrodes surface via photochemical reaction of benzophenone derivatives

Abstract

New photo-crosslinkable benzophenone-containing a polyelectrolyte was prepared by the copolymerization of [2-(acryloyloxy)ethyl]dimethyl propyl ammonium bromide (AEPAB), styrene (ST), 2-hydroxyethylmethacrylate (HEMA) and 4-acryloxybenzophenone (BPA). Pretreatment of the alumina substrate with 4-(3-triethoxysilylpropyloxy)benzophenone (2) containing a silane-coupling agent was performed to anchor the humidity-sensitive membrane to the alumina substrate through a covalent bond. The sensors were irradiated with UV light, causing the electronically excited benzophenone molecules to undergo a crosslinking reaction. The photo-crosslinked copolymer AEPAB/ST/ HEMA/BPA=70/23/5/2 showed a resistance of 6.8 M-0.882 k between 20 and 95%RH. The water durability, long-term stability under various environments, hysteresis and response and recovery times were measured and evaluated as water durable humidity sensors.

Water-resistive humidity sensor prepared by printing process using polyelectrolyte ink derived from new monomer

“…It has been found that these systems can be successfully sensitized towards UV and visible light. [22][23][24][25][26] The rheological properties of polyelectrolyte ink are specifically tailored for the printing process, which involves ink discharge through a fine screen that is automatically controlled using a blade. Central to this approach is the design of inks that are capable of flowing through a screen and then set immediately to facilitate shape retention of the deposited feature.…”

Experimental Study of Interfacial Fracture Toughness in a SiNx/PMMA Barrier Film

“…The third treatment to enhance interfacial adhesion was explored through the formation of primary bonds between SiN x and PMMA by using an organosilane-based surface modification technique. This method was previously reported by Prucker et al and used to modify the surface of silicon nitride by creating strong covalent bonds. − Benzophenone derivatives of organosilanes have also long been used to improve the adhesion strength of polymer based interfaces but to the best of our knowledge, there is very limited quantitative adhesion data reported thus far. − Dauskardt et al used FPB tests for an organosilane (γ–methacyloxypropyltrimethoxy with acrylic monomers) treated Co–Cr–Mo prosthetic surface coated with PMMA film and found the interfacial adhesion strength to improve by a factor of 2 . However, silane modification techniques have never been adopted to maximize the adhesion strength of barrier structures and therefore, in this study, the interfacial adhesion strength using benzophenone derivatives of organosilanes was explored and compared with the other methods described above.…”

Preparation of flexible resistive humidity sensors with different electrode gaps by screen printing and their humidity-sensing properties

“…5,6 Because of its high molecular weight, polymeric humidity-sensitive polyelectrolyte is limited to the dip-coating and spin-coating method. [7][8][9][10][11][12] A polymeric humidity sensor by ink-jet printing has been reported. [13][14][15][16] The ink-jet and silk-screen printing methods are intrinsically compatible with flexible film electrodes, such as flexible printed circuit boards, and are expected to reduce the deflection of characteristics of sensors.…”