Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Sci Rep. 2017 Jan 23;7:41327. doi: 10.1038/srep41327.
Light-induced shape transformations represent a fundamental step towards the emergence of adaptive materials exhibiting photomechanical behaviours. Although a range of covalent azobenzene-based photoactive materials has been demonstrated, the use of dynamic photoisomerization in mesostructured soft solids involving non-covalent co-assembly has received little attention. Here we prepare discrete micrometre-sized hydrated particles of a hexagonally ordered polyelectrolyte-surfactant mesophase based on the electrostatically induced co-assembly of poly(sodium acrylate) (PAA) and trans-azobenzene trimethylammonium bromide (trans-azoTAB), and demonstrate unusual non-equilibrium substrate-mediated shape transformations to complex multipodal microarchitectures under continuous blue light. The microparticles spontaneously sequester molecular dyes, functional enzymes and oligonucleotides, and undergo self-division when transformed to the cis state under UV irradiation. Our results illustrate that weak bonding interactions in polyelectrolyte-azobenzene surfactant mesophases can be exploited for photo-induced long-range molecular motion, and highlight how dynamic shape transformations and autonomous division can be activated by spatially confining azobenzene photomechanics in condensed microparticulate materials.
光致形状转变代表了向具有光机械行为的自适应材料出现的基本步骤。尽管已经证明了一系列基于共价偶氮苯的光活性材料，但在涉及非共价共组装的介观软固体中动态光异构化的应用却很少受到关注。在这里，我们制备了离散的微米级水合颗粒，该颗粒基于聚（丙烯酸钠）（PAA）和反式偶氮三甲铵溴化物（trans-azoTAB）的静电诱导共组装形成的六方有序聚电解质-表面活性剂介相，并且在连续蓝光下证明了不寻常的非平衡基底介导的形状转变为复杂的多足微结构。微粒子自发地隔离分子染料、功能酶和寡核苷酸，并且在紫外光照射下转变为顺式状态时会发生自分裂。我们的结果表明，在聚电解质-偶氮苯表面活性剂介相中的弱键合相互作用可以被利用来进行光诱导的长程分子运动，并强调了如何通过在凝聚的微颗粒材料中空间限制偶氮苯的光机械来激活动态形状转变和自主分裂。
