Thin Polyelectrolyte Multilayers Made by Inkjet Printing and Their Characterization by Nanomechanical Cantilever Sensors

Abstract

Measurements with nanomechanical cantilever (NMC) sensors often reveal only qualitative results. Here we overcome this issue by inkjet printing well-defined polyelectrolyte multilayers (PEMs). We present a method that allows fabricating a 40 bilayer (BL) thick and 5 mm long line made of poly(allylamine hydrochloride) (PAH) and polystyrene sulfonate (PSS). NMC sensors were used to quantify the uptake of water in thin PEMs. We measured and analyzed the mass loading and the swelling response of the PEMs upon exposure to relative humidity between 5% and 80%. For a film made of 5 BLs we determined a Young's module of ∼390 MPa for low humidity (<5%). Thicker PEM films made by 10 BLs exhibited a higher Young's module of ∼560 MPa. The Young's module decreased in both cases to 2−3 MPa at 80% relative humidity. Furthermore, the NMC measurements of mass and swelling upon exposure to humidity indicated a thickness-dependent swelling of the PEMs.

Time–Temperature and Time–Water Superposition Principles Applied to Poly(allylamine)/Poly(acrylic acid) Complexes

“…[25][26][27] Consequently, PEC physical properties have proven to be affected by water content, salt, and pH. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] This enables PECs for several applications including humidity sensors, 43,44 adhesives, 45 self-healing materials, [46][47][48][49] and mechanically adaptive materials. 50 To date, it is generally accepted that water content and temperature affect the mechanical properties of PECs.…”

“…50 To date, it is generally accepted that water content and temperature affect the mechanical properties of PECs. [28][29][30][31][32][33][34] However, there is little information regarding the dynamic mechanical behavior of PECs as a function of both water content and temperature. A fundamental understanding is needed to not only reveal how polyelectrolyte chains behave dynamically within the complex but also for enabling certain applications.…”

Young's modulus of plasma‐polymerized allylamine films using micromechanical cantilever sensor and laser‐based surface acoustic wave techniques

“…Recently, we described the possibility of calculating E of polymer films made by layer‐by‐layer deposition of polyelectrolytes (≤20 nm thickness) on the micromechanical cantilever sensor (MCS) . The swelling of polymer films in a solvent vapor environment was transduced into a measurable bending of MCS .…”

Viscous Force Retards Initial Droplet Spreading

“…Based on the above electrical method, the spreading radius was calculated by Equation 3and (5). Comparison of spreading radius got by the electrical method and images is shown Figure 3b.…”