Labrot Vincent, De Kepper Patrick, Boissonade Jacques, Szalai István, Gauffre Fabienne
Centre de Recherches Paul Pascal (CNRS), Av. Schweitzer, F-33600 Pessac, France.
J Phys Chem B. 2005 Nov 24;109(46):21476-80. doi: 10.1021/jp055095b.
The first experimental evidence of a chemomechanical mechanism leading to morphogenetic instabilities is demonstrated experimentally. The system consists of a pH-responsive gel that swells at high pH and shrinks at low pH, and a bistable reaction system exhibiting an acid steady state (pH approximately 2) and an alkaline steady state (pH approximately 10). Within the gel, the steady state selection depends on the gel size. We show that in a constant and uniform nonequilibrium chemical environment, the responsive gel undergoes large amplitude dynamical deformations under the form of travelling contraction waves and complex spatio-temporal volume oscillations. These deformations are coupled to concentration patterns of protons. We present different sequences of dynamical behaviors observed under various controlled chemical conditions. A simple heuristic model is proposed to account for the observations. These experiments open a new route for pattern formation driven by chemical energy, in soft matter systems.
导致形态发生不稳定性的化学机械机制的首个实验证据得到了实验验证。该系统由一种在高pH值下膨胀、在低pH值下收缩的pH响应凝胶，以及一个呈现酸性稳态（pH约为2）和碱性稳态（pH约为10）的双稳态反应系统组成。在凝胶内部，稳态选择取决于凝胶大小。我们表明，在恒定且均匀的非平衡化学环境中，响应凝胶会以行波收缩和复杂的时空体积振荡的形式经历大幅度动态变形。这些变形与质子的浓度模式相关联。我们展示了在各种受控化学条件下观察到的不同动态行为序列。提出了一个简单的启发式模型来解释这些观察结果。这些实验为软物质系统中由化学能驱动的图案形成开辟了一条新途径。
