Jha Anushka, Gryska Stefan, Barrios Carlos, Frechette Joelle
Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.
3M Center, 3M Company, Building 201-4N-01, St. Paul, Minnesota 55144-1000, United States.
Langmuir. 2024 Feb 27;40(8):4267-4276. doi: 10.1021/acs.langmuir.3c03413. Epub 2024 Feb 15.
Fluid-infused (or swollen) elastomers are known for their antiadhesive properties. The presence of excess fluid at their surface is the main contributor to limiting contact formation and minimizing adhesion. Despite their potential, the mechanisms for adhesion and contact aging to fluid-infused elastomers are poorly understood beyond contact with a few materials (ice, biofilms, glass). This study reports on adhesion to a model fluid-infused elastomer, poly(dimethylsiloxane) (PDMS), swollen with silicone oil. The effects of oil saturation, contact time, and the opposing surface are investigated. Specifically, adhesion to two different adherents with comparable surface energies but drastically different mechanical properties is investigated: a glass surface and a soft viscoelastic acrylic pressure-sensitive adhesive film (PSA, modulus ∼25 kPa). Adhesion between the PSA and swollen PDMS [with 23% (w/w) silicone oil] retains up to 60% of its value compared to contact with unswollen (dry) PDMS. In contrast, adhesion to glass nearly vanishes in contact with the same swollen elastomer. Adhesion to the PSA also displays stronger contact aging than adhesion to glass. Contact aging with the PSA is comparable for dry and unsaturated PDMS. Moreover, load relaxation when the PSA is in contact with the PDMS does not correlate with contact aging for contact with the dry or unsaturated elastomer, suggesting that contact aging is likely caused by chain interpenetration and polymer reorganization within the contact region. Closer to full saturation of the PDMS with oil, adhesion to the PSA decreases significantly and shows a delay in the onset of contact aging that is weakly correlated to the poroelastic relaxation of the elastomer. Additional confocal imaging suggests that the presence of a layer of fluid trapped at the interface between the two solids could explain the delayed (and limited) contact aging to the oil-saturated PDMS.
流体注入（或肿胀）的弹性体以其抗粘附性能而闻名。其表面存在过量流体是限制接触形成和使粘附最小化的主要因素。尽管它们具有潜力，但除了与少数几种材料（冰、生物膜、玻璃）接触外，人们对流体注入弹性体的粘附和接触老化机制了解甚少。本研究报告了对一种模型流体注入弹性体聚二甲基硅氧烷（PDMS）的粘附情况，该弹性体用硅油进行了肿胀处理。研究了油饱和度、接触时间和相对表面的影响。具体而言，研究了与两种具有可比表面能但力学性能差异极大的不同粘附体之间的粘附：玻璃表面和柔软的粘弹性丙烯酸压敏胶膜（PSA，模量约为25 kPa）。与未肿胀（干燥）的PDMS接触相比，PSA与肿胀的PDMS[含23%（w/w）硅油]之间的粘附力保留了高达60%的值。相比之下，与相同的肿胀弹性体接触时，与玻璃的粘附力几乎消失。与PSA的粘附力也比与玻璃的粘附力表现出更强的接触老化。PSA的接触老化对于干燥和未饱和的PDMS来说是相当的。此外，当PSA与PDMS接触时的负载松弛与与干燥或未饱和弹性体接触时的接触老化不相关，这表明接触老化可能是由接触区域内的链互穿和聚合物重组引起的。随着PDMS更接近油的完全饱和，与PSA的粘附力显著降低，并且接触老化的开始出现延迟，这与弹性体的孔隙弹性松弛弱相关。额外的共聚焦成像表明，在两种固体之间的界面处存在一层被困流体可以解释对油饱和PDMS延迟（且有限）的接触老化。
