Metal-Free Electrically Conductive Bioinspired Adhesive Polymers

Abstract

The traditional electrically conductive adhesives (ECAs) include heterogeneous metallic and/or carbon-based fillers blended with the organic adhesive polymer matrix. However, those heterogeneousblended ECAs have serious challenges with aggregation, weight, synthetic complexity, large filler contents, and price. This work reports a metal-free, high-performance, and electrically conductive fully organic polymer adhesive, poly(N-methacryloyl-3,4-dihydroxyl-L-phenylalanineco-3-sulfopropyl methacrylate):poly(3,4-ethylenedioxythiophene) (PMS:PEDOT), that is excellently dispersible in water, easy-to-use, lightweight, highly flexible, and biocompatible and has a low-process temperature (23 °C). The new ECA, PMS:PEDOT is prepared in two steps. First, a flexible linker containing copolymer, which possesses the bioinspired adhesive moiety catechol and sulfonate, is synthesized by radical polymerization. Second, EDOT is oxidatively polymerized in the presence of the flexible copolymer matrix to prepare the new ECA (PMS:PEDOT). The PMS:PEDOT exhibits high electrical conductivity up to 2.5 S/cm after annealing and glycerol addition. The bulk adhesion test (lap shear strength tests) showed 1.62 MPa which is much higher than various other commercial adhesives such as epoxy, glass bonder, and ethylene vinyl acetate-based hot melt. This newly developed ECA successfully demonstrates an efficient electrical connection on a circuit board and PET film. This work introduces a new class of materials, a fully organic conducting polymer adhesive, which will become essential for fast growing applications including conducting ink, bioelectronics, batteries, photovoltaics, and ultrathin microsized electronic devices.

Switchable Photonic Bio‐Adhesive Materials

“…Essentially, Mylar was biaxially oriented polyethylene terephthalate (BOPET), which was manufactured by extruding the molten polymer (PET) onto a chill roll to provide high strength and stiffness (modulus about 4 GPa), which enabled its usage as a robust substrate for lap shear adhesion tests. [ 5 ] These measurements of the Mylar films resulted in an elastic modulus of 3.4 ± 0.06 GPa (Figure S57, Supporting Information) in agreement with that reported in literature. The Mylar film was transparent, flexible, and durable, making it an ideal substrate for both adhesion strength and color change monitoring.…”

“…The adhesive strength under different conditions was characterized using a lap shearing test with CAM films sandwiched between Mylar strips (Figure 3c and Figure S27, Supporting Information). [5,13] The adhesion strength decreases dramatically, by two orders of magnitude, to 5 ± 2 KPa in the wet state (Figure 3c and Figure S27, Supporting Information). The shear modulus decreases fourfold from 70.2 ± 2.1 kPa at 42% RH to 18.9 ± 6.2 kPa at 97% RH (Figure 3c and Figures S28 and S29, Supporting Information, see evaluation of capillary forces in Supporting Information).…”

Co‐Assembly of Biosynthetic Chiral Nematic Adhesive Materials with Dynamic Polarized Luminescence

“…The lap shear mechanical test was conducted for adhesive films placed between hydrophobic PET substrates ( Figure a and Figures S3 and S4, Supporting Information). [ 34,35 ] CNC–PEI and CNC–PAA materials exhibited high adhesion strength of 1.8 ± 0.4 and 0.7 ± 0.1 MPa, respectively, which was much higher than that observed for individual CNC, PEI, and PAA components (Figure 3b,c). Adding polyelectrolytes significantly increased the interfacial strength of CNC matrices by providing functional groups that can bond with PET through abundant hydrogen bonding and hydrophobic interactions.…”

Surface adhesion engineering for robust organic semiconductor devices

“…5b, poly( N -methacryloyl-3,4-dihydroxyl- l -phenylalanineco-3-sulfopropyl methacrylate) (PSS) containing adhesive catechol groups was oxidatively polymerized with conductive poly(3,4-ethylenedioxythiophene) (PEDOT) to obtain a fully organic polymer adhesive with a high electrical conductivity, namely PMS:PEDOT. 52 PMS:PEDOT demonstrated an adhesion strength of 2.53 × 10 −1 MPa, which is 6.4 times higher than that of PMTS:PEDOT. It is supposed that the dihydroxy groups of catechol (hydrogen bond donor) can be bonded to the surface of polyester (ester group-hydrogen bond acceptor) through hydrogen bonds.…”

“…Recently, several strategies have been proposed to enhance the interfacial adhesion of organic semiconductors to supporting substrates, including introducing additional adhesive layers between the interfaces of organic semiconductors and supporting substrates 45–49 (termed as adhesive layer introduction), functionalizing organic semiconductors with adhesive chemical groups 50–53 (termed as adhesive group functionalization), integrating adhesive linkers and organic semiconducting units into one chemical entity (termed as an adhesive integrated agent), and physically mixing organic semiconductors with various adhesive additives 54–56 (termed as physical mixing) (Fig. 1).…”