Tack Properties of Nanostructured Epoxy-Amine Resins on Plasma-Treated Glass Substrates.

A probe tack test, coupled with in situ imaging, was used to evaluate the influence of an air plasma treatment on glass substrates on the fracture energy of nanostructured epoxy-amine resins. Nanostructuration was achieved by the addition of thermoplastic triblock copolymers. The influence of the surface treatment was assessed by splitting the fracture energy (tack energy) into three main contributions (cavitation, viscous flow, and stretch). We showed that before gelation, the interfacial strength depended on the nature of the copolymers and on their interaction with grafted functions (R-COOH and R-C=O) by air plasma treatment. The latter also influenced the cohesion of the resins, impacting the copolymers' phase separation and, as a consequence, conversion rate. The tack test, coupled with rheology and thermal (differential scanning calorimetry) measurements, was relevant to explain how the balance of interactions contributed to the fracture energy up to the gel point.

Polyaryletherketone Based Blends: A Review.

This review aims to report the status of the research on polyaryletherketone-based thermoplastic blends (PAEK). PAEK are high-performance copolymers able to replace metals in many applications including those related to the environmental and energy transition. PAEK lead to the extension of high-performance multifunctional materials to target embedded electronics, robotics, aerospace, medical devices and prostheses. Blending PAEK with other thermostable thermoplastic polymers is a viable option to obtain materials with new affordable properties. First, this study investigates the miscibility of each couple. Due to different types of interactions, PAEK-based thermoplastic blends go from fully miscible (with some polyetherimides) to immiscible (with polytetrafluoroethylene). Depending on the ether-to-ketone ratio of PAEK as well as the nature of the second component, a large range of crystalline structures and blend morphologies are reported. The PAEK-based thermoplastic blends are elaborated by melt-mixing or solution blending. Then, the effect of the composition and blending preparation on the mechanical properties are investigated. PAEK-based thermoplastic blends give rise to the possibility of tuning their properties to design novel materials. However, we demonstrate hereby that significant research effort is needed to overcome the lack of knowledge on the structure/morphology/property relationships for those types of high-performance thermoplastic blends.

Immobilization of surface non-affinitive protein onto a metal surface by an external electric field.

We investigated an alternate technique to coat the surface with a protein having no surface affinity, without the use of any exotic chemical agents. An external electric field was utilized to prepare the protein coating on a metal substrate. Stainless steel (St) substrate and lysozyme (LSZ) were used as the surface to be coated and the model non-adsorptive protein, respectively. Dynamics of the adsorption of LSZ on the St surface in the presence and absence of an external electric potential (EEP) were monitored by in-situ ellipsometry. Applying negative surface potential (-0.4 V vs Ag/AgCl) forced the adsorption of LSZ onto the St surface where LSZ did not adsorb without applying any EEP. The repetition of the EEP-application and -cut-off indicated the controllability of the LSZ coating amount depending on the total duration of the EEP-application. The coated LSZ largely remained bound to the surface even by the cut-off of the external electric field, the ratio of which to the detached amount was roughly constant (approximately 7:3). Furthermore, the LSZ coated surface on the St substrate was found to be reversibly switched between being affinitive and non-affinitive to a typical model protein adsorbate (bovine serum albumin) by the EEP-application and cut-off.