Currently, material extrusion 3D printing (ME3DP) based on fused deposition modeling (FDM) is considered a highly adaptable and efficient additive manufacturing technique to develop components with complex geometries using computer-aided design. While the 3D printing process for a number of thermoplastic materials using FDM technology has been well demonstrated, there still exists a significant challenge to develop new polymeric materials compatible with ME3DP. The present work reports the development of ME3DP compatible thermoplastic elastomeric (TPE) materials from polypropylene (PP) and styrene-(ethylene-butylene)-styrene (SEBS) block copolymers using a straightforward blending approach, which enables the creation of tailorable materials. Properties of the 3D printed TPEs were compared with traditional injection molded samples. The tensile strength and Young’s modulus of the 3D printed sample were lower than the injection molded samples. However, no significant differences could be found in the melt rheological properties at higher frequency ranges or in the dynamic mechanical behavior. The phase morphologies of the 3D printed and injection molded TPEs were correlated with their respective properties. Reinforcing carbon black was used to increase the mechanical performance of the 3D printed TPE, and the balancing of thermoplastic elastomeric and mechanical properties were achieved at a lower carbon black loading. The preferential location of carbon black in the blend phases was theoretically predicted from wetting parameters. This study was made in order to get an insight to the relationship between morphology and properties of the ME3DP compatible PP/SEBS blends.

Roll-to-roll hot embossing could revolutionize the manufacturing of multifunctional polymer films with the ability to process large area at a high rate with reduced cost. The continuous hot embossing of the films, however, has been hindered due to the lack of durable and flexible molds, which can replicate micro and nanofeatures with reliability over several embossing cycles. In this work, we demonstrate for the first time the fabrication of a flexible polymer (polyimide) mold from the commercially available sheet by a maskless photolithography approach combined with inductively coupled plasma etching and its potential application to the roll-to-roll hot embossing process. The flexible polyimide mold consisted of holes with controlled dimensions: diameter: 14 μm, spacing: 16.5 μm, and depth: 6.8 μm. The reliability of flexible polyimide mold was tested and implemented by embossing micron-sized features on a commercial thermoplastic polymer, polyamide, and thermoplastic elastomer (TPE) sheet. The polyimide mold replicated micron-sized features on polymer substrates (polyamide and TPE) with excellent fidelity and was durable even after numerous embossing cycles.

Reentrant structures have been deemed necessary for repelling low‐surface‐tension liquids. In this article, a novel manufacturing methodology using the roll‐to‐roll process to enable continuous manufacturing of reentrant structures over large areas on a polymeric film was demonstrated. A two‐stage process, composed of embossing followed by post‐compression, allowed the fabrication of reentrant structures, which cannot be easily fabricated using other processes over large areas in a continuous manner. The treatment of the reentrant surface structures with an additional coating of 1H,1H,2H,2H‐perfluorooctyltrichlorosilane layer provided liquid repellency with contact angles of 155 and 140°, respectively, for water (Ylv = 72 mN m−1) and diiodomethane (Ylv = 50 mN m−1). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46980.

Many surfaces in nature such as the lotus leaf, cicada wings, water spider legs and gecko feet have attracted attention due to their inherent superhydrophobicity and self-cleaning properties. These surfaces are characterized by water contact angles greater than 150° and contact angle hysteresis < 10°. In this work, a continuous fabrication methodology for production of such superhydrophobic surfaces consisting of well-ordered micro-pillar structures (aspect ratio greater than 1 (1.3)) on a large area polyamide film using roll-to-roll hot embossing process was demonstrated. It was found that the temperature played a significant role in replication. Incomplete replication was observed in regime 1 (150 to 155 °C) and the height of replication was influenced by nip pressure and roll speed due to viscosity variations. In contrast, complete replication was seen in regime 2 (190 to 195 °C) and the height of replication was insensitive to nip pressure and roll speed due to a fairly constant viscosity value. The embossed polyamide surface, once coated with a low surface energy 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane (PFTS) monolayer, showed super-repellant characteristics with respect to water and demonstrated a successful manufacturing approach to fabricate superhydrophobic surfaces.

Functional surfaces with attractive properties, such as superhydrophobicity and omniphobicity often rely on the synergy between intrinsic material properties and dual scale micro‐ and nano‐hierarchical structures for achieving desired wettability. Historically, engineered liquid repellent surfaces have attracted a great deal of interest from academia and industry due to their broad application prospects. Hence, for several years, there have been significant scientific efforts by researchers exploring state of the art manufacturing technologies that are efficient and yet cost effective to produce functional liquid repellent surfaces at an industrial scale. This technical review summarizes the various advanced and state of the art polymer processing technologies employed to fabricate the micro‐ and nanostructured polymer surfaces, with a special focus given to superhydrophobic and omniphobic applications. Here, we discuss the merits and limitations of each fabrication methods available for micro‐ and nanostructuring of polymer‐based surfaces. In addition, an attempt has been made to provide insight into the relationship between geometry of micro/nanostructures (size and shape) and intrinsic wettability on liquid repellency. A special section has been devoted to feature and document all commercialization efforts, including various commercially available products that were developed in the past decade. Finally, outlook and the development trend in the polymer micro‐ and nanostructured surfaces are highlighted to lead future research.