We present a simple and facile method for long-term preservation of hydrophilicity of oxygen plasma-hydrophilized poly (dimethylsiloxane) (PDMS) by cold storage. We show that storage under temperature of − 80 °C can maintain superhydrophilicity of plasma-exposed PDMS for at least 100 days. Storage at − 15 °C and at 22 °C room temperature (RT) is shown to exhibit, respectively, about half and full recovery of the original hydrophobicity after 100 days in storage. Furthermore, we investigated the implications of the cold storage for microfluidic applications, the capillary filling rate and the ability of the flow to bypass geometrical obstacles in a microfluidic channel. It is shown that the preservation of capillary filling properties of microchannels is in close agreement with the contact angle (CA) measurements and that the colder the storage temperature, the better the capillary filling capability of the channels is preserved. We ascribe the significantly reduced recovery rate to reduced thermally activated relaxation phenomena such as diminished diffusion of low molecular weight species (LMW) in the polymer matrix at colder temperatures. This is supported by ATR-FTIR measurements of the OH vibration band over time for samples stored at different temperatures.

我们提出了一种简单而容易的方法，用于通过冷藏来长期保存氧等离子体亲水化的聚二甲基硅氧烷（PDMS）的亲水性。我们显示，在− 80°C的温度下存储可以使暴露于血浆的PDMS的超亲水性保持至少100天。储藏100天后，在− 15°C和22°C的室温下（RT）的存储分别显示出原始疏水性的约一半和全部恢复。此外，我们研究了冷库对微流体应用的影响，毛细管填充率以及流体绕过微流体通道中的几何障碍的能力。结果表明，微通道的毛细管填充性能的保持与接触角（CA）的测量结果非常吻合，并且存储温度越低，通道的毛细管填充能力就越好。我们将回收率的显着降低归因于热活化松弛现象的减少，例如在较低温度下低分子量物质（LMW）在聚合物基质中的扩散减少。对于不同温度下存储的样品，ATR-FTIR随时间推移对OH振动带进行的测量支持了这一点。我们将回收率的显着降低归因于热活化松弛现象的减少，例如在较低温度下低分子量物质（LMW）在聚合物基质中的扩散减少。对于不同温度下存储的样品，ATR-FTIR随时间推移对OH振动带进行的测量支持了这一点。我们将回收率的显着降低归因于热活化松弛现象的减少，例如在较低温度下低分子量物质（LMW）在聚合物基质中的扩散减少。对于不同温度下存储的样品，ATR-FTIR随时间推移对OH振动带进行的测量支持了这一点。