Smart Materials Andreas Lendlein,* [a] Yujun Feng,* [b] Dirk W. Grijpma,* [c] and Yuanjin Zhao* [d] Smart Materials are able to respond to changes in their envi- ronment in a predetermined way, and research in the field of functional materials is often motivated by potential applica- tions. Smart polymers are especially of technological signifi- cance in view of the grand global challenges including energy generation and storage, sustainability, and healthcare. Being smart also involves the individual tailoring of properties and functions to specific purposes. Therefore, smart materials’ design requires an immensely broad approach. In this special issue, emphasis is given to responsive polymers, shape- memory polymers, nano-/micro-sized polymeric objectives, and application-driven materials. In addition, fabrication schemes of smart materials are considered. Responsive Polymers Among all the intelligent materials, polymers may be most readily responsive to environmental stimulation, as their func- tional groups can be tailored to accommodate to a fascinating range of stimulation modes. Song and co-workers (DOI: 10.1002/cphc.201701367) found that the spontaneous emis- sion of a perovskite embedded in polymer opal structures ex- hibits clear amplified signatures. Wang’s team (DOI: 10.1002/ cphc.201800095) showed how to obtain a low background for early diagnosis of diseases through electrochemically respon- sive superhydrophilic surfaces exhibiting specific cell capture and release with high yields and extremely low nonspecific ad- hesion. While some polymers modify their behavior in reaction to a given trigger, most processes in daily life are reliant on re- sponsiveness to multiple stimuli. Gianneschi, Abbott, and co- workers (DOI: 10.1002/cphc.201800106) taught how to manip- ulate multi-scale responses of liquid crystals by interfacial as- semblies of cleavable homopolymers with mesogenic side chains that can be split upon exposure to either H 2 O 2 or UV light. Wang’s group (DOI: 10.1002/cphc.201701145) construct- ed photo- and thermal dually responsive smart surfaces by grafting silicon nanowire arrays onto a copolymer of spiropyr- an and N-isopropylacrylamide to overcome the low efficiency of cancer-cell capture and release by single-responsive smart surfaces. Deng, Zhong, and co-workers (DOI: 10.1002/ cphc.201701367) developed integrated multifunctional micelles through co-self-assembly of poly(ethylene glycol)-b-poly(l- lysine) derivatives with natural ferulic acid or lipoic acid. Apart from the potential applications in biomedicine, the petroleum industry is undoubtedly another promising arena to embrace the use of responsive polymers, so as to satisfy the variation of temperature and salinity when going deep into the underground formation. Su and Feng (DOI: 10.1002/ cphc.201800190) reviewed the cutting-edge development of unique thermo-viscosifying polymers and up-to-date laborato- ry trials at various stages of oil and gas production. Shape-memory Polymers A method that allows controlled manipulation and shape- memory effect (SME) quantification of individual micro- and nano-objects in analogy to macroscopic thermomechanical test procedures is introduced by Lendlein et al. (DOI: 10.1002/ cphc.201701362). An atomic force microscope is applied to ad- dress individual electro-spun poly(ether urethane) (PEU) micro- or nanowires freely suspended between two micropillars on a micro-structured silicon wafer substrate. An excellent shape- memory performance of the PEU microwires (diameter of 1.0 Æ 0.2 mm) becomes apparent (high strain fixity and recovery ratios) with this technique and the switching temperature could be adjusted by variation of the deformation tempera- ture. A single PEU nanowire with a diameter of (98 Æ 27) nm exhibited an impressive maximum recovery stress of s max = (33.3 Æ 0.1) MPa. Efficient indirect heating of thermally triggered shape- memory polymers could be realized by incorporation of poly- dopamine particles (PDAP) in polyurethanes. The PDAPs, which exhibit strong NIR absorption, high photothermal conversion efficiency, and photostability, can form hydrogen bonds with the polyurethane matrix. An SME in a composite material con- taining only 0.01 wt% PDAP could be induced within 60 s ex- posure time to NIR irradiation (Xia et al., DOI: 10.1002/ cphc.201800022). A multiple SME with three temporary shapes besides the per- manent shape could be programmed in a ternary polymeric composite. Mather and co-workers created the polymeric ma- Editorial DOI: 10.1002/cphc.201800578 [a] Prof. Dr. A. Lendlein Institute of Biomaterial Science, Helmholtz-Zentrum Geesthacht Kantstr. 55, 14513 Teltow (Germany) E-mail : andreas.lendlein@hzg.de [b] Prof. Dr. Y. Feng Polymer Research Institute, Sichuan University No. 24, Southern Section 1, Yihuan Road, Chengdu 610065 (China) E-mail : yjfeng@scu.edu.cn [c] Prof. Dr. D. W. Grijpma University of Twente, Department of Biomaterials Science and Technology Drienerlolaan 5, 7522 NB, Enschede (The Netherlands) E-mail: d.w.grijpma@utwente.nl [d] Prof. Dr. Y. Zhao State Key Laboratory of Bioelectronics School of Biomedical Science and Medical Engineering Southeast University, Sipailou 2, Nanjing 210096 (China) E-mail : yjzhao@seu.edu.cn The ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/cphc.201800578. ChemPhysChem 2018, 19, 1938 – 1940 # 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 1938