Low-temperature operating adhesive films capable of in-situ use of moisture with outstanding water-resistant capacity

Adhesives with properties of low-temperature and water-resistance are important in manufacturing. In this work, dopamine hydrochloride (DA), containing catechol groups, was introduced into the polymer by covalent grafting to obtain water-resistant films. Films with low-temperature and water-resistance properties were obtained through layer-by-layer assembly of branched polyethyleneimine (bPEI) and chemically cross-linked hyaluronate (HA)-DA (denoted HA-D). The film surfaces were wetted with moisture generated from low-temperature pretreatment, and the resulting films, named as bPEI/HA-D multilayer films, could adhere strongly by manual application of pressure of about 0.8 MPa. High transmittance (>= 78%) was confirmed by ultraviolet-visible absorption spectroscopy, and the adhesion was determined by lap shear tests. Results indicated that the bPEI/HA-D multilayer films had excellent adhesive strengths and were insensitive to temperature, when stored at -20 degrees C (1.08 +/- 0.54 MPa), in 100% relative humidity (0.54 +/- 0.22 MPa), under ambient conditions (0.99 +/- 0.29 MPa), which suggests their potential applications in optical fields and special environments, such as underwater or at low temperature.