Graphene-polydimethylsiloxane/chromium bilayer-based flexible, reversible, and large bendable photomechanical actuators

Abstract

We demonstrate the fabrication of highly versatile photomechanical actuators based on graphene-polymer/metal bilayers that offers fast, low-cost fabrication, large deflection, reversible actuation under zero applied pre-strain, and wavelength-selective response. The photomechanical actuator consists of a graphene nanoplatelet (GNP)-polydimethylsiloxane (PDMS) nanocomposite with a thin chromium metal coating of 35 nm thickness on the backside of the structure. The photomechanical response of the GNP-PDMS/Cr photomechanical actuator was measured by recording the variation of the bending angle upon infrared (IR) light illumination. The bending in the bilayer actuator is caused by the generation of thermal stress due to the large mismatch (the ratio being 1/20) of the thermal expansion coefficient between the two layers as a result of IR absorption by GNPs and a subsequent increase in the local temperature. The maximum bending angle was found to be about 40 degrees with a corresponding large deflection value of about 6–7 mm within 6 s for IR illumination with an intensity of 550 mW cm−2. The corresponding actuation response and relaxation times were about 1 and 3 s, respectively. The GNP-PDMS/Cr bilayer combination when integrated with the standard surface micromachining technique of micro-electromechanical system fabrication can find useful applications in the realization of micro soft-robotics, controlled drug delivery, and light-driven micro switches i.e. micro-optomechanical systems.

Controllably coated graphene oxide particles with enhanced compatibility with poly(ethylene-co-propylene) thermoplastic elastomer for excellent photo-mechanical actuation capability

“…One of the most important class from the application point of view are photo-thermal actuators, which are uniform composite systems consisting of a flexible elastomeric matrix and various functional fillers promoting interactions with photons [2]. Carbon particles such as carbon nanotubes (CNTs) [1,3], graphene oxide [1,6], graphene [7,8] etc., are extensively used as fillers in these systems thanks to their excellent both thermal and mechanical properties.…”

Carbon‐Based Photothermal Actuators

“…Because graphene has many exceptional physical properties, it has attracted considerable interests in various scientific fields including photothermal actuators . Notably, graphene has several advantages for photothermal actuator design, including i) high light absorption ability, ii) excellent mechanical strength, iii) high thermal conductivity, iv) distinctively negative coefficient of thermal expansion (CTE), and v) ultralight weight. Because of the high photothermal conversion efficiency, graphene holds great promise in high‐efficiency light energy utilization, photothermal therapy, and photothermal devices .…”

Interfacial Fabrication of CNTs/PVDF Bilayer Actuator with Fast Responses to the Light and Organic Solvent Vapor Stimuli

“…To date, many actuators consisting of carbon nanomaterials and polymer layer still display slow responses (tens of seconds to a few minutes) and insufficient sensitivity in the actuation/recovery process triggered by solvent vapors and [ 7,13,14 ] light stimuli. [ 15–19 ] Zhang et al. [ 20 ] and Deng et al.…”

“…To date, many actuators consisting of carbon nanomaterials and polymer layer still display slow responses (tens of seconds to a few minutes) and insufficient sensitivity in the actuation/recovery process triggered by solvent vapors and [7,13,14] light stimuli. [15][16][17][18][19] Zhang et al [20] and Deng et al [21] reported respectively thermally and solvent responsive actuators with bilayer CNT/polyethylene composite, and graphene/epoxybased polymer. These actuators can be bent reversibly in water or acetone under the controlled of thermal and near-infrared light.…”