Thermally-induced two-way shape memory polymers: Mechanisms, structures, and applications

Artificial reactor containing polymeric bilayer architectures for the formation of self-controlled tandem catalytic-ability

“…The artificial reactor showed the desired shape-memory effect. This outcome, as known, may be related to the thermosensitive polymeric networks in the shape-memory layer [16]. The switching between the open-and closed networks induced the shape change in this reactor.…”

“…NMP-A-MIP-Ag and NMP-S-MIP-Ag were the non-switchable reactors that were prepared by replacing the switchable shape-memory layer with non-shape-memory layers ('NMP'). For the preparation of the two control groups, the thermosensitive component (i.e., 2-nonenoic acid) in the shape-memory layer of SMP-MIP-Ag was replaced with non-thermosensitive acrylic acid (marked by 'A' in NMP-A-MIP-Ag) and styrene (marked by 'S' in NMP-S-MIP-Ag), which did not contain thermosensitive networks [16,17] and were therefore lack of the responsive properties. One more purpose for such replacement was to form a much stronger hydrophilic and hydrophobic environment in NMP-A-MIP-Ag and NMP-S-MIP-Ag, which allowed either open or closed access to the first layers in the two control groups.…”

“…By borrowing the polymeric 'soft' properties and divisional concept from natural systems, this artificial reactor was fabricated with polymeric bilayer architectures that allowed finely controlling the tandem processes and accordingly avoided the potential competition of different catalytic sites. As outlined in Figure 1, the first layer, which may be responsible for the occurrence of a precedent reaction (such as catalytic hydrolysis), consisted of a reactive shape-memory polymer made of poly(2-acrylamido-2-methylpropanesulfonic acid-co-2-nonenoic acid) (PAMD) that contained thermosensitive polymeric networks [16]. The second layer, which provided access to the succeeding reaction, was made of an intermediate-imprinted poly(acrylamide) (PAA) hydrogel and encapsulated Ag nanoparticles.…”

Brush‐Paintable, Temperature and Light Responsive Triple Shape‐Memory Photonic Coatings Based on Micrometer‐Sized Cholesteric Liquid Crystal Polymer Particles

“…Shape‐memory polymers (SMPs) are fascinating stimuli‐responsive materials that exhibit irreversible shape‐changes upon external stimuli such as light, temperature, or humidity. [ 1,2 ] SMPs have the ability to achieve and retain a temporal shape through the so‐called “programming” to further recover their original shape upon application of a specific stimulus. [ 3,4 ] In particular, shape‐memory photonic structures, such as photonic crystals and cholesteric liquid‐crystalline (CLC) polymers, have received attention as they exhibit simultaneous shape and structural color changes upon temperature changes.…”

Smart polymer nanocomposites: A review

“…Smart materials are attracting increasing interest especially in the era of the fourth industrial revolution (Industry 4.0) and circular economy. Smart polymer nanocomposites (SPN) which can be derived from shape memory polymer [3][4][5][6], stimuli-active polymers [7], smart electrorheological (ER) and magnetorheological (MR) polymer [8][9][10][11], self-healing polymer [12,13], self-cleaning polymer [14][15][16][17], self-heating polymer [18], self-sensing polymer [19], energy-harvesting and energy storage polymer [20][21][22][23][24][25][26][27] are the latest hot research topics. The addition of nanofiller can increase the performance of the SPN (e.g., shape fixity, shape recovery, self-healing ability) due to their high specific surface area, nucleating effects, reinforcing effects, and inherent functionalities (e.g., thermal conductivity, electrical conductivity) [3].…”