Water-responsive actuators have been an increasing interest in various applications. In this work, water-responsive actuators based on bilayer composite film were prepared using commercialized PVA and SBS by a two-step...

Shape‐morphing materials that can exhibit various shape deformations are highly desirable. In this work, shape‐morphing materials with diverse deformation modes are prepared via a facile approach of constructing bilayer structures of SEBS/paraffin blends with different melting temperatures. The bilayer films are prepared using a simple solvent‐coating adhesion method, either by adhering two single‐layers together and stretching or by adhering two pre‐stretched single‐layers. These bilayer films show strong interfacial adhesion due to the similar chemical composition of the two layers. By adjusting the programming method, stretching strain, and thickness ratio, the shape deformation behaviors of the resultant bilayer films can be flexibly tuned. To demonstrate the wide applicability of this approach, several 2D sheets with hinge structures as well as a smart dressing are prepared, in which the former can be transformed into 3D configurations and the latter can automatically fit to the human body and peel off. Owing to the advantages of low cost, easy and large‐scale preparation, recyclability, and high designability, the approach for preparing shape‐morphing bilayer films proposed by this work is versatile and the obtained bilayer films have the potential to satisfy the demands of divergent application fields.

The reconfigurable and reprocessable thermadapt two‐way shape memory polymers (2W‐SMPs) are highly desirable for many advanced biomimetic applications, but the preparation of these polymers with economical raw materials and convenient approaches still remains a challenge. In this work, thermadapt 2W‐SMPs based on a dual crosslinking network are synthesized by linking polyethylene glycol with hydroxylated modified SBS via dynamic covalent bonds. Benefiting from the synergistic effect of combining a dynamic covalent network and a physical cross‐linking network, the thermadapt 2W‐SMPs exhibit a good balance of mechanical properties and favorable two‐way shape memory effect (2W‐SME) with the reversible actuation strain of 11.9%. The 2W‐SMPs can be reprocessed and transformed into complex 3D shapes after multiple folding processes due to the dynamic covalent exchange as well as the reversible physical crosslinking, and the obtained new samples still exhibit good 2W‐SMEs. Furthermore, the transition temperature of 2W‐SMPs is designed to be close to human body temperature, and it is manufactured into a biomimetic mimosa actuator that can undergo shape changes through finger contact and cooling. This work provides a new idea for the development of thermadapt 2W‐SMPs, and the obtained materials show great potential applications in intelligent actuators.

ABSTRACT. The aim of this study was to explore the interaction effects of hardness (75A, 80A, 90A), structures of tread groove (spacing, width, depth and orientation) and contaminants (dry, wet and vegetable oil) on coefficient of friction (COF) of TPU outsole of high-heeled shoe, by application the SATRA whole shoe tester with normalized ceramic tile. Results of univariate analysis show that (1) in the dry condition, orientation of tread groove was the main factor impacting the COF of TPU outsole; (2) 'Orientation * contaminant', 'Hardness * contaminant' and 'Orientation * hardness * contaminant' had significant interaction impact on COF; (3) COF at the hardness of 80A was lower than that of 70A and 90A in the dry condition; while, those in the wet and oil conditions were controversial. Overall, variables of hardness, contaminant and orientation of tread groove were main influence factors in terms of slip resistance.KEY WORDS: coefficient of friction; hardness; contaminants; tread groove INFLUENŢA CANELURILOR, DURITĂŢII ŞI CONTAMINANŢILOR ASUPRA REZISTENŢEI LA ALUNECARE A TĂLPILOR PANTOFILOR CU TOC ÎNALTREZUMAT. Scopul acestui studiu a fost acela de a explora efectele interacţiunii dintre duritate (75A, 80A, 90A), structura canelurilor tălpilor (distanţă, lăţime, adâncime şi orientare) şi contaminanţi (uscat, cu apă şi cu ulei vegetal) asupra coeficientului de frecare (COF) al tălpilor din TPU la pantofii cu toc înalt, utilizând dispozitivul SATRA pentru testarea întregului pantof cu plăci ceramice normalizate. Rezultatele analizei univariate arată că: (1), în stare uscată, orientarea canelurilor a reprezentat principalul factor care a influenţat COF al tălpii din TPU; (2) combinaţiile "Orientare * contaminant", "Duritate * contaminant" şi "Orientare * duritate * contaminant" au avut un impact semnificativ asupra COF; (3) COF la duritatea 80A a fost mai mic decât în cazul durităţilor 70A şi 90A în stare uscată, iar valorile obţinute în condiţii de contaminare cu apă şi cu ulei au fost controversate. În general, duritatea, contaminanţii şi orientarea canelurilor au reprezentat principalii factori care influenţează rezistenţa la alunecare.