Biomimetic Slippery PDMS Film with Papillae-Like Microstructures for Antifogging and Self-Cleaning

Xiaoming Feng,Ze Wang,Zhiwu Han,Huiying Guan,Shichao Niu

doi:10.3390/coatings11020238

Abstract

Transparent materials with antifogging and self-cleaning ability are of extreme significance for utilization in outdoor solar cell devices to alleviate the performance loss and maintenance costs. Herein, with inspiration from the anti-wetting surfaces in nature, regular papillae-like microstructure arrays (PMAs) inspired by lotus leaves were designed via a common UV lithography combined with a soft replication. Subsequently, the biomimetic slippery polydimethylsiloxane (PDMS) film (BSPF) inspired by the pitcher plant was fabricated successfully by infusing with hydrophobic liquid lubricant. The resultant surface has hydrophobic surface chemistry, a slippery interface, PMAs structure. The wettability, optical characteristic, antifogging property and self-cleaning ability of the PMAs-based BSPF were characterized experimentally. The film displays excellent optical transmittance, antireflection, antifogging, and self-cleaning properties, which is superior to the flat PDMS film (FPF). Remarkably, an average reflection of ∼11.3% in the FPF was reduced to ∼8.9% of the BSPF. In addition, after gradient spray test for 120 s, the antifogging efficiency was close to 100% for the BSPF surface in comparison with the flat PDMS film (FPF), biomimetic PDMS film (BPF) and flat slippery PDMS film (FSPF) (35%, 70% and 85%). Furthermore, we also discovered that the BSPF surface exhibited a better self-cleaning performance toward a variety of liquids than solid dust.

Highlights

Fogging brings problems in many different fields where materials with outstanding optical performance are required [1,2,3,4,5,6,7]
We designed the surface topographies taking the form of a regular papillae-like microstructure arrays (PMAs) inspired from lotus leave on the PDMS substrate
We had confirmed that the UV lithography combined with a soft replication worked successfully to achieve the PDMS film with PMAs

Summary

Introduction

Fogging brings problems in many different fields where materials with outstanding optical performance are required [1,2,3,4,5,6,7]. Inspired by lotus leaves employ PDMS as substrate, the surface topographies taking the form of a regular papillae-like microstructure arrays was designed, and combines the pitcher plant-inspired lubricant-infused “slippery” surfaces, using hydrophobic liquid lubricant as modifier. In this preparation, the SU-8 negative template was fabricated by a common UV lithography. The wettability, optical characteristic, antifogging property and self-cleaning ability of the PMAs-based BSPF were characterized in detail. The prepared BSPF surface improves optical transmittance, and shows excellent antireflective, antifogging, and self-cleaning properties, which is superior to the flat PDMS film (FPF). It can provide useful information to design more ingenious engineering products with desirable functionalities in the future

Materials and Chemical Reagents

Characteristics of the Prepared Samples

Observation of Fog Drops Condensation

Results and Discussion

Conclusions