生物传感器：MPEG-TK-COOH可用于设计响应性材料，当环境变化时（如还原环境或pH值变化）会发生降解或释放信号，具有潜在的生物传感功能。

Repeat step 1 with ethanoic acid into a separate test-tube. Add 5 drops of Universal Indicator to each test-tube and record the pH, or use a pH meter to record the pH. You should find that ...