Coating apparatus

Abstract

A plasma deposition apparatus for applying a plasma deposited polymeric coating to items, the apparatus comprising: a plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber, a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system, and a structure for locating items between the electrodes; and a load lock chamber communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber.

Description

[0001] COATING APPARATUS TECHNICAL FIELD This invention relates to plasma deposition of polymeric coatings. In particular, though not exclusively, this invention relates to a plasma deposition apparatus, a plasma deposition chamber, an electrode, a monomer delivery element, and a method for applying a polymeric plasma-deposited coating. The invention also relates to an associated computer program, data processing system and computer-readable medium. BACKGROUND Plasma deposition of polymeric coatings has been known for some time. Such coatings can be useful, for example, as protective coatings for items. There are many circumstances in which it can be advantageous to protect an item by applying a protective coating. For example, it may be desirable to protect an item from damage caused by liquids, dust, chemicals, or temperature extremes. A variety of items can benefit from protective coatings, for example including electronic devices or components thereof, clothing, footwear, and laboratory equipment. WO98 / 58117 discloses that perfluoroalkyl chain monomers can be used for generating hydrophobic surfaces from pulsed plasma deposition processes. On inception, this technique was used to form relatively thin, splash-resistant coatings, which derived their water repellence predominantly from functional retention of fluorocarbon chains. WO2016 / 198855 and WO2016 / 198857 disclose plasma deposition of polymeric barrier coatings displaying enhanced crosslinking onto electronic devices and their components. Such coatings can protect items against liquids even upon immersion. In a plasma deposition of a polymeric coating, in general, the item to be treated is placed within a plasma deposition chamber together with a monomer, a suitable voltage is applied between electrodes, and a glow discharge is ignited within the chamber. The nature and quality of the coating depends on the deposition conditions, which are in turn underpinned by the construction and geometry of the plasma deposition apparatus and process parameters. Examples of process parameters that must be selected and tuned are the nature of the monomer, the nature of the item, the power applied, the pressure within the chamber, the flow rate of the monomer, the duration of the exposure, and the optional presence of any carrier gasses in the chamber. Most plasma deposited polymeric coatings are applied at sub-atmospheric pressure, which requires pressure cycling. To minimise pressure cycling time and reduce the number of 1 deposition apparatus requiring tuning, it is accepted wisdom in the art to strive for relatively large plasma deposition chambers that can be used to coat large batches of items. As the demand for protective coatings has risen, the size of such chambers has increased. However, there are limits to practicable chamber sizes. The nature, consistency and quality of resultant coatings are of concern and often a limiting factor on scale. There remains a need to increase throughput in plasma deposition of polymeric coatings. SUMMARY OF THE INVENTION From a first aspect, the invention provides a plasma deposition apparatus for applying a plasma deposited polymeric coating to items, the apparatus comprising: a plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber, a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system, and a structure for locating items between the electrodes; and a load lock chamber communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber. It has been found that location of items can allow for more targeted tuning of process parameters to deliver higher deposition rates. Unexpectedly, the time required for plasma deposition can be significantly reduced. This is of additional benefit when combined with a load lock chamber because the load lock chamber may allow pressure cycling time to be reduced or eliminated as a factor in overall processing time. Advantageously, the structure may be configured to locate items in a deposition zone within an electrode cavity bounded by the electrodes. The electrode cavity may be central within the deposition chamber. Advantageously, all electrodes of the deposition chamber may bound the electrode cavity and the electrode cavity may be the sole electrode cavity of the deposition chamber. An electrode cavity may be defined as any space between at least two electrodes. The deposition zone may in principle be any void within the electrode cavity where a plasma deposited polymeric coating can be applied to items. Advantageously, the electrodes may be exposed to the deposition zone. In other words, there may be nothing but a void between the deposition zone and the electrodes. It has been found that a void between the electrodes and the deposition zone aids controlled, rapid and effective coating. Obstructions between the electrodes and items coated in the deposition zone make accurate tuning of process parameters considerably more challenging, which undermines controlled, rapid and effective coating. 2

[0002] Suitably, a lateral boundary of the electrodes may be within or in register with a lateral boundary of the deposition zone. The deposition zone may extend from an imaginary plane or axis between the electrodes towards the electrodes, the imaginary plane or axis optionally being central to the electrode cavity. Advantageously, the deposition zone may extend no more than two thirds, or optionally no more than halfway to the electrodes. Suitably, the imaginary plane or axis may be parallel to or coincide with a plane or axis of symmetry associated with one or more of: (i) the electrodes; (ii) the monomer delivery system; and (iii) the chamber. In some embodiments, the imaginary plane or axis may be parallel with one or more electrode faces of the electrodes. Suitably, the structure may be arranged to locate items centrally within the deposition zone. The structure may be arranged to locate a plurality of items in the deposition zone concurrently, optionally in a coplanar arrangement. Optionally, the structure may be arranged to locate items, suitably all items to be concurrently coated, within a single plane, optionally along a central plane between the electrodes. Advantageously, the structure may be arranged to locate items, suitably all items to be concurrently coated, in an unstacked or non-overlapping configuration. For example, all items to be concurrently coated can advantageously be arranged in a single coplanar configuration. It has been found that overlapping items in the deposition zone can undermine accurate control of deposition conditions and is thus, counterintuitively, a barrier to controlled, rapid and effective processing. Suitably, the structure may be arranged to locate items, suitably all items to be coated, in a position where they are directly exposed to the electrodes. For example, the structure may be arranged such that items, suitably all items to be concurrently coated, are located such that an upper surface of the item is exposed to an upper electrode of the deposition chamber and a lower surface of the item is exposed to a lower electrode of the deposition chamber. Conveniently, the structure may comprise a locating indentation or formation on or integral with a wall of the deposition chamber. For example, the structure may comprise one or more wall projections, indentations or attachments. 3

[0003] Advantageously, the structure may comprise a transport mechanism for moving and locating items between the electrodes. Suitably, the transport mechanism may also be for moving items out away from a position between the electrodes. Suitably, the transport mechanism may comprise one or more actuators attached to one or more walls of the chamber. Optionally, the one or more actuators may comprise a plurality of driven rollers. Advantageously, the one or more actuators may comprise first and second sets of rollers on opposed chamber walls. The transport mechanism may comprise a drive for driving the one or more actuators. For example, the drive may comprise a belt and motor. Optionally, the transport mechanism may be capable of moving items beyond an opening of the deposition chamber. Similarly, the transport mechanism may be capable of moving items into the deposition chamber from outside the deposition chamber. The structure may comprise a mobile support locatable in the deposition chamber to support and locate one or more items between the electrodes. Advantageously, the mobile support may comprise an indentation or formation for engaging an indentation or formation mounted on or integral with a wall of the deposition chamber, to locate the support in the deposition chamber. Conveniently, the support may comprise a frame. The frame may suitably have one or more indentations or formations for locating one or more items. Optionally, the frame may comprise a fixing for affixing an item thereto. Suitably, a transport mechanism of the structure may be co-operable with the support to move and locate the support to bring items into and out of position between the electrodes. Optionally, the support may comprise one or more indentations or formations for engaging the transport mechanism. Optionally, the support may be co-operable with the transport mechanism to allow the support to be moved by the transport mechanism from beyond an opening of the chamber. Advantageously, the support may be co-operable with the transport mechanism to locate items in a single plane between the electrodes, with the items exposed to the electrodes without obstruction. The electrodes may optionally be identical in structure. The structure may be arranged to locate items in a deposition zone and the electrodes arranged symmetrically about the deposition zone. 4

[0004] Advantageously, the electrodes may comprise or consist of a pair of opposed electrodes. The opposed pair of electrodes may be mirrored. One or more of the electrodes may comprise a plurality of power connections, the power connections optionally being regularly spaced or symmetrical. In some embodiments, one or more of the electrodes each comprise a plurality of positive connections and a plurality of negative connections. One or more of the electrodes may comprise gaps, optionally in a regular pattern. Suitably, one or more of the electrodes may comprise a major face facing a deposition zone in which the structure is arranged to locate items. Advantageously, one or more of the electrodes may comprise an array of connected electrode elements, the electrode elements optionally comprising pipes. Optionally, one or more of the electrodes may be mounted to a wall of the chamber with a body of the electrodes offset from the wall of the chamber. Suitably, one or more of the electrodes may comprise a plurality of posts for mounting the electrode to a wall of the chamber. Conveniently, the posts may comprise a power connection, a temperature control fluid connection, or both. Advantageously, the electrodes may be mounted on major walls of the chamber. Suitably, the deposition chamber may be oblong in cross-section and have a minor and a major cross-sectional axis and the electrodes may be mounted on walls of the chamber that are parallel with the major cross-sectional axis of the chamber. One or more of the electrodes may comprise a temperature control mechanism. Suitably, the temperature control mechanism may comprise a channel within the electrode for receiving a temperature control fluid. Advantageously, the channel may be defined by an array of electrode elements, optionally comprising pipes. Optionally, the temperature control mechanism may comprise or be connected to a source of temperature control fluid, optionally a water heating system. The monomer delivery system may comprise a plurality of inlet holes, suitably an array thereof. The monomer delivery system is suitable for delivering monomer. In embodiments, it may alternatively or additionally be used to deliver gases. For example, it may be useful to introduce gases into the deposition chamber for activation or to control the deposition environment. 5

[0005] Suitably, the monomer delivery system may comprise inlet holes on an opposed side of one or more of the electrodes relative to the deposition zone. Optionally, all inlet holes of the monomer delivery system may be on an opposed side of one or more of the electrodes relative to the deposition zone. Conveniently, the inlet holes, suitably an array thereof, may be formed in a removable monomer delivery plate associated with one or more walls of the chamber. Suitably, the monomer delivery plate may be flush with one or more walls of the chamber. Advantageously, the monomer delivery plate may be associated with one or more walls of the chamber comprising a temperature control system. Optionally, the deposition chamber is oblong in cross-section and has a minor and a major cross-sectional axis and the monomer delivery plate may be mounted on a wall of the chamber that is parallel with the major cross-sectional axis of the chamber. Advantageously, a majority of the inlet holes may be within a lateral boundary of one of the electrodes. Optionally, the inlet holes may be arranged symmetrically about a deposition zone in which the structure is arranged to locate items. Suitably, the inlet holes may comprise or consist of opposed arrays of inlet holes, optionally mirrored. Suitably, the monomer delivery system may comprise a plurality of feed channels for feeding monomer to an array of inlet holes. Advantageously, the plurality of feed channels may be regularly spaced or symmetrical. In some embodiments the monomer delivery system may comprise a monomer delivery control mechanism configured such that the rate of monomer delivery through at least first and second ones of the feed channels can be independently controlled. Optionally, the monomer delivery system may comprise a source of monomer vapour . Suitably, the chamber may comprise walls defining internals of greater width and length than height, with an opening at each longitudinal end. Advantageously, the plasma deposition chamber may comprise one or more temperature- controlled walls, optionally temperature controlled by a temperature control mechanism comprising a channel for receiving a temperature control fluid. Optionally, the temperature control mechanism may comprise or be connected to a source of temperature control fluid, optionally a water heating system. 6

[0006] Optionally, the deposition chamber may be oblong in cross-section and have a minor and a major cross-sectional axis, and one or more major walls of the chamber parallel with the major cross-sectional axis of the chamber may be temperature controlled. Advantageously, the deposition chamber may have a volume of less than 300 litres. For example, the chamber may suitably have a volume in the range of from 25 to 200 litres, suitably in the range of from 75 to 150 litres. The deposition chamber may comprise a RF power supply for powering the electrodes. Suitable RF frequencies are known in the art, for instance 13.56 MHz or multiples thereof. The deposition chamber may comprise a pressure control system for cycling the internals of the chamber to sub-atmospheric pressure. Advantageously, the deposition chamber may comprise a sealable opening for receiving and / or removing items. Optionally, the deposition chamber may comprise a plurality of sealable openings for receiving and / or removing items. In some embodiments, the deposition chamber is a pass-through chamber comprising a first sealable opening for receiving items and a second sealable opening for removing items. Suitably one or more sealable openings of the plasma deposition chamber may be controlled by a gate valve. The load lock may comprise a pressure control system for cycling the internals of the load lock chamber to sub-atmospheric pressure. Suitably, the load lock may be communicable with the plasma deposition chamber via a sealable opening, optionally comprising a gate valve. Advantageously, the load lock may be in direct communication with the plasma deposition chamber. Alternatively, the load lock may, for example, be in communication with the plasma deposition chamber via one or more buffer chambers. Conveniently, the plasma deposition apparatus may be a pass-through apparatus comprising a first load lock communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber and a second load lock communicable with the plasma deposition chamber to remove items from the plasma deposition chamber. The first and second load locks may optionally be in communication with the plasma deposition chamber via sealable openings at opposed ends of the plasma deposition chamber. In some embodiments, the first and second load lock chambers are of the same structure. 7

[0007] Advantageously, the load lock chamber may comprise a transport mechanism for moving items into the deposition chamber. Suitably, the load lock chamber may comprise a transport mechanism for moving items out of the deposition chamber. In some embodiments, the transport mechanism comprises one or more actuators attached to one or more walls of the load lock chamber. Suitably wherein the one or more actuators may comprise a plurality of driven rollers. Optionally, the one or more actuators may comprise first and second sets of rollers on opposed chamber walls. The transport mechanism may comprise a drive for driving the one or more actuators. Suitably, the transport mechanism of the load lock chamber the transport mechanism may be capable of moving items beyond an opening of the load lock chamber and optionally maybe capable of moving items into the load lock chamber from outside the load lock chamber. In some embodiments, complementary transport mechanisms of the deposition chamber and the load lock chamber may cooperate to bridge an opening or gap between the chambers so as to be able to move items into or out of the deposition chamber via the load lock chamber. Optionally, the apparatus may comprise a plurality of movable modules. For example, the apparatus may comprise separate skids for supporting the deposition chamber and the load lock chamber. In some embodiments, the apparatus may be integrated into a continuous assembly line and may be configured to coat items proceeding in the assembly line in a continuous manner. The plasma deposition chamber of the plasma deposition apparatus of the first aspect of the invention itself represents a second aspect of the invention. Thus, from a second aspect, there is provided a plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber, a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system, and a structure for locating items between the electrodes. The plasma deposition chamber may optionally be as defined in respect of the plasma deposition chamber in the first aspect of the invention. A third aspect of the invention provides a method of applying a plasma deposited polymeric coating to an item with a plasma deposition chamber or plasma deposition apparatus according to any aspect or embodiment of the invention, the method comprising: locating the item between the electrodes of the plasma deposition chamber using the structure of 8

[0008] the plasma deposition chamber; and delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the item. The coating may be a liquid repellent or barrier coating. In some embodiments, the method comprises applying the plasma deposited polymeric coating with a plasma deposition apparatus comprising a load lock chamber, for example as defined in respect of the first aspect of the invention, and includes the steps of: a) placing the item into the load lock chamber of the apparatus; b) moving the item from the load lock chamber into the plasma deposition chamber of the apparatus; c) locating the item between the electrodes of the plasma deposition chamber using the structure of the plasma deposition chamber; d) delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the item; and e) moving the item out of the deposition chamber. Suitably, the method may comprise applying a plasma deposited coating to a plurality of items in a continuous manner by repeating a) to e) whilst maintaining the plasma deposition chamber at sub-atmospheric pressure. Optionally, e) may comprise moving items out of the plasma deposition chamber via a second load lock chamber, for example provided in a pass-through apparatus. Advantageously, the load lock chamber may be loaded with an item and brought to sub- atmospheric pressure whilst a coating is concurrently applied to another item in the plasma deposition chamber. Similarly, an item may be removed via a load lock whilst a coating is concurrently applied to another item in the plasma deposition chamber. In some embodiments, moving the item may comprise activating a transport mechanism of the apparatus. Advantageously, the method may comprise applying the plasma deposited coating in the deposition chamber in under 600 seconds, optionally in under 300 seconds, or indeed in under 200 seconds. 9

[0009] Suitably, the method may comprise maintaining chamber walls of the plasma deposition chamber at a temperature in the range of from 40 to 70 degrees C, optionally in the range of from 45 to 60 degrees C. Conveniently, the method may comprise running a cleaning cycle before and / or after applying the coating. Optionally, the cleaning cycle may comprise striking a plasma in the deposition chamber without delivering monomer through the monomer delivery system. Suitably, a gas may be delivered through the monomer delivery system, optionally oxygen. Optionally, the method may comprise delivering monomer to the plasma deposition chamber at a rate in the range of from 1 to 15 mL / min. Optionally, the method may comprise applying a pulsed power to the electrodes. Suitably the duty cycle of the pulsed power may be in the range of from 0.1 to 10%, suitably in the range of from 1% to 5%. Suitably the power density may be in the range of from 0.5 to 70 W / litre of chamber volume, optionally in the range of from 10 to 60 W / litre of chamber volume. Optionally, the item may comprise an electronic device or component thereof. It is well known that electronic devices and their components are sensitive to damage caused by contamination by liquids such as environmental liquids, in particular water. Contact with liquids, either in the course of normal use or as a result of accidental exposure, can lead to short circuiting between electronic components and irreparable damage to circuit boards, electronic chips etc. The electronic device can, for example, be selected from the group of small portable electronic equipment such as mobile phones, smartphones, pagers, radios, hearing aids, laptops, notebooks, tablet computers, phablets and personal digital assistants (PDAs). These devices can be exposed to significant liquid contamination when used outside or inside in close proximity of liquids. Such devices are also prone to accidental exposure to liquids, for example if dropped in liquid or splashed. In some embodiments, the item comprises a printed circuit board. Suitably, locating the item between the electrodes of the plasma deposition chamber may comprise locating the item centrally within a deposition zone of the plasma deposition chamber. Advantageously, the method may comprise coating a plurality of items concurrently by locating a plurality of items between the electrodes of the plasma deposition chamber, optionally in a coplanar arrangement. 10

[0010] Suitably, the method may comprise locating items, suitably all items to be concurrently coated, within or along only one plane within a deposition zone of the deposition chamber, optionally a central plane between the electrodes. Advantageously, the method may comprise arranging items, suitably all items to be concurrently coated, in an unstacked or non-overlapping configuration during coating. For example, all items to be concurrently coated can advantageously be located between the electrodes in a single coplanar configuration. It has been found that overlapping items in the deposition zone undermine accurate control of deposition conditions and are thus, counterintuitively, a barrier to controlled, rapid and effective processing. Suitably, the method may comprise locating item or items in a position where they are directly exposed to the electrodes. For example the item, suitably all items to be concurrently coated, may be located such that an upper surface of the item is exposed to an upper electrode of the deposition chamber and a lower surface of the item is exposed to a lower electrode of the deposition chamber. Suitably, the method may comprise placing one or more items in a frame of a transport mechanism of the deposition chamber. The monomer may suitably comprise one or more unsaturated monomeric species. The one or more monomeric species may optionally be substantially free from fluorine. In some embodiments, one or more of the monomeric species may comprise an (i) an aromatic moiety and (ii) a carbonyl moiety. Such species are disclosed, for example, in WO 2020 / 169975. Generally, the aromatic moiety is an optionally substituted aromatic moiety. In an embodiment, the optionally substituted aromatic moiety is an optionally substituted monocyclic aromatic moiety or an optionally substituted bicyclic aromatic moiety. The optionally substituted aromatic moiety may for example contain from 3 to 12 carbon atoms. The optionally substituted aromatic moiety may be an aryl group, such as a monocyclic or bicyclic aryl group. The optionally substituted aromatic moiety may be a C3-C12aryl group, a C5-C12aryl group, a C5-C10aryl group, a C5-C8aryl group, or a C5-C6aryl group. In an embodiment, the optionally substituted aromatic moiety does not contain heteroatoms. Preferably, the optionally substituted aromatic moiety is an optionally substituted phenyl group. The phenyl group may be unsubstituted or may be substituted with one or more substituents; the substituents may for example be selected from one or 11

[0011] more alkyl groups. The one or more alkyl groups may, for example, be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl. In another embodiment, the optionally substituted aromatic moiety contains heteroatoms. The optionally substituted aromatic moiety may be an optionally substituted heteroaryl group, such as a monocyclic or bicyclic heteroaryl group. The optionally substituted heteroaryl group may contain from 1 to 12 carbon atoms and one or more N, O or S atoms. The heteroaryl group may be a 5 or 6-membered ring containing one or more N atoms. The optionally substituted aromatic moiety may be an arylene group, such as a monocyclic or bicyclic arylene group. The optionally substituted aromatic moiety may be a C3-C12arylene group, a C5-C12arylene group, a C5-C10arylene group, a C5-C8arylene group, or a C5-C6arylene group. In an embodiment, the optionally substituted aromatic moiety does not contain heteroatoms. Preferably, the optionally substituted aromatic moiety is an optionally substituted phenylene group. The phenylene group may be unsubstituted or may be substituted with one or more substituents; the substituents may for example be selected from one or more alkyl groups. The one or more alkyl groups may, for example, be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl. In another embodiment, the optionally substituted aromatic moiety contains heteroatoms. The optionally substituted aromatic moiety may be an optionally substituted heteroarylene group, such as a monocyclic or bicyclic heteroarylene group. The optionally substituted heteroarylene group may contain from 1 to 12 carbon atoms and one or more N, O or S atoms. The heteroarylene group may be a 5 or 6-membered ring containing one or more N atoms. Throughout this specification, unless expressly stated otherwise: - An “optionally substituted” group may be unsubstituted, or substituted with one or more, for example one or two, substituents. These substituents may, for example, be selected from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl and heterocyclyl groups; carboxylic acids and carboxylate ions; carboxylate esters; carbamates; alkoxyl groups; ketone and aldehyde groups; amine and amide groups; –OH; –CN;–NO2; and halogens. - An alkyl group may be a straight or branched chain alkyl group. The alkyl group may be C1to C27alkyl, C1to C20alkyl, C1to C12alkyl, C1to C10alkyl, C1to C8alkyl, C1to C6alkyl, C1to C5alkyl, C1to C4alkyl, C1to C3alkyl, or C1to C2alkyl. The alkyl group may, for example, 12 be selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl. - A cycloalkyl group may be C3to C8cycloalkyl, C3to C7cycloalkyl, C3to C6cycloalkyl, C4to C6cycloalkyl, or C5to C6cycloalkyl. - An alkylene group may be a straight or branched chain alkylene group. The alkylene group may be C1to C27alkylene, C1to C20alkylene, C1to C12alkylene, C1to C10alkylene, C1to C8alkylene, C1to C6alkylene, C1to C5alkylene, C1to C4alkylene, C1to C3alkylene, or C1to C2alkylene. - A halogen group may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I); preferably fluorine (F). The one or more monomeric species are unsaturated. The use of unsaturated monomeric species allows the use of lower activation energies than would be required for saturated monomeric species. This helps to avoid fragmentation of the monomeric species during the plasma process, giving better structural retention and improved barrier coating quality. The one or more unsaturated monomeric species may comprise a monomer compound A which is unsaturated and comprises (i) an aromatic moiety and (ii) a carbonyl moiety. The aromatic moiety may be an optionally substituted aromatic moiety as defined above. In an embodiment, the monomer compound A comprises moiety (α) or(β): wherein each R is independently selected from hydrogen, halogen, optionally substituted branched or straight chain alkyl (e.g. C1-C6alkyl), or optionally substituted cycloalkyl (e.g. C3-C8cycloalkyl). In these embodiments, the carbonyl moiety (ii) forms part of moiety (α) or (β). 13 The functionalities in moieties (α) and (β), which can include e.g. an acrylate moiety or a vinyl ester moiety, can stabilise radicals during polymerisation. Suitably, the monomer compound A can comprise (i) an aromatic moiety which is linked to (ii) a moiety capable of assisting radical polymerisation comprising a carbonyl moiety. The moiety capable of assisting radical polymerisation may also be capable of facilitating low- energy polymerisation. The moiety capable of assisting radical polymerisation can be linked to the aromatic moiety either directly or via a linker moiety. Preferably, the moiety capable of assisting radical polymerisation is moiety (α) or (β) as defined above. In one embodiment, the monomer compound A is a compound of formula (I): wherein Q is selected from structures (Qa), (Qb), (Qc) and (Qd): wherein each of R1, R2and R3is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, or optionally substituted C3-C8cycloalkyl; Z is a direct bond or a linker moiety; and Ar is an optionally substituted aromatic moiety. 14 When Q is selected from structures (Qc) and (Qd), each of R1, R2and R3can be independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl, preferably wherein R3is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n- pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl and R2and R1are hydrogen. Preferably, the monomer compound A is a compound of formula (I): wherein Q is selected from structures (Qa) and (Qb): wherein each of R1, R2and R3is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, or optionally substituted C3-C8cycloalkyl; Z is a direct bond or a linker moiety; and Ar is an optionally substituted aromatic moiety. In an embodiment, each of R1, R2and R3is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n- hexyl, isohexyl, and 3-methylpentyl. In an embodiment, each of R1, R2and R3is independently selected from hydrogen, methyl and ethyl. In an embodiment, each of R1, R2and R3is independently selected from hydrogen or methyl. In an embodiment, R1and R2are both hydrogen. In an embodiment, R1and R3are both hydrogen. In an embodiment, R2and R3are both hydrogen. In an embodiment, each of R1, R2and R3is hydrogen. 15 In an embodiment, Q is structure (Qa) as defined above. In an embodiment, Q is structure (Qb) as defined above. When Q is structure (Qa), the monomer compound A is a compound of formula (Ia): wherein R1, R2, R3, Z and Ar are as defined above. In an embodiment, the compound of formula (Ia) is selected from benzyl acrylate, phenyl acrylate and 2-phenylethyl acrylate. Preferably, the compound of formula (Ia) is benzyl acrylate. When Q is structure (Qb), the monomer compound A is a compound of formula (Ib): wherein R1, R2, R3, Z and Ar are as defined above. When Q is structure (Qc), the monomer compound A is a compound of formula (Ic): wherein R1, R2, R3, Z and Ar are as defined above. 16 When Q is structure (Qd), the monomer compound A is a compound of formula (Id): wherein R1, R2, R3, Z and Ar are as defined above. Preferably R3is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl and R2and R1are each hydrogen. In a preferred embodiment, the formulae are (Ia) and (Ib). In formulae (I), (Ia), (Ib), (Ic) and (Id), Ar represents an optionally substituted aromatic moiety. The optionally substituted aromatic moiety can be as defined above. In formulae (I), (Ia), (Ib), (Ic) and (Id), Z represents a direct bond or a linker moiety. In an embodiment, Z is a direct bond. In an embodiment, Z is a linker moiety. Suitably, Z may be an optionally substituted alkylene group, such as for example a C1-C27alkylene, which is unsubstituted or substituted by one or more substituents which may e.g. be selected from hydroxy, C1-C12alkoxy, C1-C12alkyl, hydroxy-C1-C12-alkyl and halogen. In an embodiment, one to ten carbon atoms in the alkylene chain are replaced by spacer moieties selected from C2-C6alkenylene, -O-, -S-, and -NR”-, wherein R” is selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, or optionally substituted C3-C8cycloalkyl. In an embodiment, the alkylene group comprises 1, 2, 3, 4 or 5 spacer moieties. In an embodiment, the alkylene group comprises 1 to 3 spacer moieties. In an embodiment, the alkylene group comprises 1 or 2 spacer moieties. In an embodiment, the alkylene group is a C1-C20alkylene. In an embodiment, the alkylene group is a C1-C10alkylene, such as a C1-C6alkylene. In an embodiment, the alkylene is a straight chain alkylene. In an embodiment, the alkylene is substituted by one or more substituents. In an embodiment, the alkylene group is unsubstituted. In an embodiment, Z has the formula: -(CH2)n- 17 where n is an integer from 0 to 27.

[0012] When n is 0, Z is a direct bond. When n is 1 or more, Z is a linker moiety.

[0013] In an embodiment, the lower value of the possible range for n is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,

[0014] 10, 11, 12, 13, 14, 15, 16 , 17, 18, 19, 20, 21, 22, 23, 24, 25 or 26 and / or the upper value of the possible range for n is 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12,

[0015] 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2. In an embodiment, n is an integer from 0 to 2, or n is 1 or 2. Preferably, n is 1.

[0016] In formulae (I), (la) and (lb), Ar is an optionally substituted aromatic moiety. The optionally substituted aromatic moiety is as defined above.

[0017] In a preferred embodiment, the monomer compound A does not contain any fluorine atoms.

[0018] Optionally, the monomer compound A does not contain any halogen atoms.

[0019] Additionally, or alternatively, the monomeric species may comprise, alone or in combination with a monomer compound A as defined hereinabove, a monomer compound B of the formula (IV): where R1, R2and R4are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl or halo alkyl or aryl optionally substituted by halo, and R3is selected from: where each X is independently selected from hydrogen, a halogen, optionally substituted branched or straight chain C1-C6alkyl, halo alkyl or aryl optionally substituted by halo; and ni is an integer from 1 to 27.

[0020] Such monomers are known from WO2016 / 198857.

[0021] Preferably, ni is from 1 to 12. Optionally ni is from 4 to 12, optionally 6 to 8.

[0022] In a preferred embodiment R3is selected from:

[0023] 18 where mi is an integer from 0 to 13 and each X is independently selected from hydrogen, a halogen, optionally substituted branched or straight chain C1-C6alkyl, halo alkyl or aryl optionally substituted by halo; and m2 is an integer from 2 to 14.

[0024] In a particularly preferred embodiment the monomer compound B is a compound of formula (IVa): wherein each of R1, R2, R4, and R5to R10is independently selected from hydrogen or an optionally substituted C1-C6branched or straight chain alkyl group; each X is independently selected from hydrogen or halogen; a is from 0 to 10, optionally 0 or 1; b is from 2 to 14, optionally from 3 to 7; and c is 0 or 1; or the monomer compound B is a compound of formula (IVb): wherein each of RlzR2, R4, and R5to R10is independently selected from hydrogen or an optionally substituted C1-C6branched or straight chain alkyl group; each X is independently selected from hydrogen or halogen; a is from 0 to 10, optionally 0 or 1; b is from 2 to 14, optionally from 3 to 7; and c is 0 or 1.

[0025] 19

[0026] The halogen may be chlorine or bromine, but is preferably fluorine for compliance with RoHS regulations (Restriction of Hazardous Substances). a is from 0 to 10, preferably from 0 to 6, optionally 2 to 4, most preferably 0 or 1. b is from 2 to 14, optionally from 2 to 10, preferably from 3 to 7. Each of R1, R2, R4, and R5to R10is independently selected from hydrogen or a C1-C6branched or straight chain alkyl group. The alkyl group may be substituted or unsubstituted, saturated or unsaturated. When the alkyl group is substituted, the location or type of the substituent is not especially limited provided the resultant polymer provides an appropriate liquid repellent and / or barrier layer. The skilled person would be aware of suitable substituents. If the alkyl group is substituted, a preferred substituent is halo, i.e. any of R1, R2, R4, and R5to R10may be haloalkyl, preferably fluoro alkyl. Other possible substituents may be hydroxyl or amine groups. If the alkyl group is unsaturated it may comprise one or more alkene or alkyne groups. Each of R1, R2, R4, and R5to R10may be independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n- hexyl, isohexyl, and 3-methylpentyl. In a preferred embodiment each of R1, R2, R4, and R5to R10is independently selected from hydrogen or methyl. In a preferred embodiment, a and c are each independently 0 or 1; and b is from 3 to 7. In one preferred embodiment each X is H. In an alternative preferred embodiment each X is F. Optionally R1and R2are both hydrogen. Optionally R4is hydrogen or methyl. Preferably R1and R2are both hydrogen and R4is hydrogen or methyl. Optionally R9is hydrogen and R10is branched or straight chain C1-C6alkyl group. In a preferred embodiment R10is methyl. In one embodiment each of R5to R8is hydrogen. In one embodiment each of R1, R2, R4, and R5to R10is hydrogen, each X is H, a=0 and c=0. In a particularly preferred embodiment the monomer compound B has the formula (IVc): 20 where n is from 2 to 10.

[0027] In another preferred embodiment the monomer compound B has the formula (IVd): where n is from 2 to 10.

[0028] The monomer compound B may be selected from 1H,1H,2H,2H-perfluorohexyl acrylate (PFAC4), 1H,1H,2H,2H-perfluorooctyl acrylate (PFAC6), 1H,1H,2H,2H-perfluorodecyl acrylate (PFAC8) and 1H,1H,2H,2H-perfluorododecyl acrylate (PFAC10).

[0029] The monomer compound B may be selected from 1H,1H,2H,2H-pefluorohexyl methacrylate (PFMAC4), 1H,1H,2H,2H-perfluorooctyl methacrylate (PFMAC6) and 1H,1H,2H,2H- perfluorodecyl methacrylate (PFMAC8).

[0030] The monomer compound B of may have the formula (IVe): wherein a and c are each independently 0 or 1, b is from 3 to 7 and n is from 4 to 10, where n=a+b+c+1.

[0031] The monomer compound B may have the formula (IVf) :

[0032] 21 where n is from 2 to 12, optionally from 2 to 10.

[0033] The monomer compound B may be selected from ethyl hexyl acrylate, hexyl acrylate, decyl

[0034] 5 acrylate, lauryl dodecyl acrylate and iso decyl acrylate.

[0035] The monomer compound B may have the formula (IVg): where n is from 4 to 14, optionally from 4 to 12.

[0036] 10 The monomer compound B may have the formula (IVh): where n is from 4 to 14, optionally from 4 to 12.

[0037] The one or more unsaturated monomeric species may comprise a crosslinking reagent.

[0038] 15 Optionally, the one or more unsaturated monomeric species may comprise a crosslinking reagent in combination with a monomer compound A and / or a monomer compound B as defined above.

[0039] Generally, the crosslinking reagent can comprise two or more unsaturated bonds attached by means of one or more linker moieties.

[0040] 22 In an embodiment, the crosslinking reagent has a boiling point of less than 500 °C at standard pressure. In an embodiment, the crosslinking reagent is independently selected from a compound of formula (II) or (III): wherein Y1, Y2, Y3, Y4, Y5, Y6, Y7and Y8are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, optionally substituted C1-C6cycloalkyl, and optionally substituted C1-C6aryl; and L is a linker moiety. In an embodiment, L contains an aromatic moiety and a carbonyl moiety. In an embodiment, L has the formula: wherein each Y9is independently selected from a bond, -O-, -O-C(O)-, –C(O)-O-, -Y11-O-C(O)-, -C(O)-O-Y11-, -O-C(O)-Y11-, -Y11-C(O)-O-, -OY11-, and –Y11O-, wherein Y11is an optionally substituted branched, straight chain or cyclic C1-C8alkylene; and Y10is selected from an optionally substituted branched, straight chain or cyclic C1-C8alkylene, an optionally substituted branched, straight chain or cyclic C1-C8ether, arylene, a siloxane group and oxygen. In an embodiment, each Y9is a bond. In an embodiment, each Y9is -O-. In an embodiment, each Y9is a vinyl ester or vinyl ether group. 23 In an embodiment, Y10has the formula: wherein each Y12and Y13is independently selected from hydrogen, halogen, optionally substituted cyclic, branched or straight chain C1-C8alkyl, or –OY14, wherein Y14is selected from optionally substituted branched or straight chain C1-C8alkyl or alkenyl, and n” is an integer from 1 to 10. In an embodiment, each Y12is hydrogen and each Y13is hydrogen, such that Y10is a linear alkylene chain. For this embodiment, Y9can for example be a vinyl ester or vinyl ether group. In an embodiment, each Y12is fluoro and each Y13is fluoro, such that Y10is a linear perfluoroalkylene chain. n” is an integer from 0 to 10. In an embodiment, the lower value of the possible range for n” is 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9 and / or the upper value of the possible range for n” is 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1. In an embodiment, n” is from 4 to 6. In an embodiment, Y10is an optionally substituted branched, straight chain or cyclic C1-C8ether. The number of ether groups in Y10is not particularly limited, and may comprise ethylene glycol units. It is generally preferred that Y10will have only a single ether group. When Y10comprises an ether group or oxygen, it is generally preferred that Y9and Y10are selected such that the crosslinking reagent contains no peroxide groups. In an embodiment, Y10has the formula: wherein each Y15is independently selected from optionally substituted branched or straight chain C1-C6alkyl. In an embodiment, each Y15is methyl. In an embodiment, each Y9is a bond. 24 In an embodiment, Y10has the formula: wherein Y16, Y17, Y18and Y19are each independently selected from hydrogen and optionally substituted branched or straight chain C1-C8alkyl or alkenyl. In an embodiment, the alkenyl group is vinyl. In an embodiment, Y18is hydrogen or vinyl, and Y16, Y17and Y19are each hydrogen. In an embodiment, each of Y16, Y17, Y18and Y19is hydrogen. In another embodiment Y18is vinyl, and Y16, Y17and Y19are each hydrogen. In an embodiment, group L has one of the following structures: In an embodiment, group L has one of the following structures: 25 For L according structure (e), Y10can for example be an alkylene chain or a cycloalkylene, such as those shown in structures (b) and (d) above. The alkylene chain may for example be a straight chain alkylene chain. When Y10is a cycloalkylene, this can for example be cyclohexylene, such as 1,4-cyclohexylene. For L according to structure (f), Y10can for example be structure (b), e.g. an alkylene chain, or structure (d1) or structure (d2). For L according to structure (g), Y10can for example be a cycloalkylene, such as the cyclohexylene according to structure (d1). For L according to structure (h), Y10can for example be structure (b). For L according to structure (i) or structure (j), Y10can for example be alkylene or cycloalkylene. Optionally the alkylene or cycloalkylene may be substituted with one or more vinyl groups or alkenyl ether groups, for example one or more vinyl ether groups. For L according to structure (j), Y10can for example be oxygen. When each Y9is a bond, each Y10may for example be any of structures (b), (c), (d1) and (d2). In an embodiment Y10is a straight chain alkylene such that the crosslinking reagent is a diene, such as for example a heptadiene, octadiene, or nonadiene; in an embodiment it is 1,7-octadiene. When each Y9is O, each Y10may for example be a branched or straight chain C1-C6alkylene, preferably a straight chain alkylene, most preferably a C4straight chain alkylene. In an embodiment the crosslinking reagent is 1,4-butanediol divinyl ether. It will be understood that each Y9group can be combined with any other Y9group and Y10group to form the crosslinking reagent. The skilled person will be aware of possible substituents for each of the cyclic, branched or straight chain C1-C8alkylene groups mentioned above. The alkylene groups may be substituted at one or more positions by a suitable chemical group. Each C1-C8alkylene group may for example be a C1-C3, C2-C6, or C6-C8alkylene group. In an embodiment, the crosslinking reagent has alkyl chains for Y10and vinyl ester or vinyl ether groups on either side. In a preferred embodiment, the crosslinking reagent does not contain any fluorine atoms. Optionally, the crosslinking reagent does not contain any halogen atoms. 26 In an embodiment, the crosslinking reagent is independently selected from divinyl adipate (DVA), 1,4-butanediol divinyl ether (BDVE), 1,4-cyclohexanedimethanol divinyl ether (CDDE), 1,7-octadiene (17OD), 1,2,4-trivinylcyclohexane (TVCH), 1,3- divinyltetramethyldisiloxane (DVTMDS), diallyl 1,4-cyclohexanedicarboxylate (DCHD), glyoxal bis(diallyl acetal) (GBDA), 1,4-phenylene diacrylate and di(ethylene glycol) divinyl ether. In an embodiment, the crosslinking reagent is divinyl adipate (DVA). In an embodiment, the crosslinking reagent is 1,4-butanediol divinyl ether (BDVE). In an embodiment, for the compound of formula (III), group L can for example be selected from a branched or straight chain C1-C8alkylene or an ether group. L may for example be a C3, C4, C5, or C6alkylene, preferably a straight chain alkylene. Chemical structures of crosslinking reagents are set out below in Table 1. Table 1: Crosslinking reagents 27 The monomer may consist of one or more monomeric species that are a monomer compound A as defined above, or of one or more monomeric species that are a monomer compound B as defined above, or indeed of one or more monomeric species that are a crosslinking reagent as defined above. Optionally, the monomer may comprise or consist of a single monomeric species that is a monomer compound A as defined above. Optionally, the monomer may comprise or consist of a single monomeric species that is a monomer compound B as defined above. Optionally, the monomer may comprise or consist of a single monomeric species that is a crosslinking reagent as defined above as defined above. 28 In various embodiments, the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a monomer compound A as defined above. In various embodiments, the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a monomer compound B as defined above. In various embodiments, the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a monomer compound A or compound B as defined above. Suitably, the monomer comprises in the range of from 0% to 90 % w / w, optionally in the range of from 5% to 50 % w / w, or even in the range of from 10% to 30 % w / w of one or more monomeric species that are a crosslinking reagent as defined above. In some embodiments, crosslinking reagent can be used by itself or as the main species. In various embodiments, the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a crosslinking reagent as defined above. Suitably, the monomer comprises in the range of from 0% to 90 % w / w, optionally in the range of from 5% to 50 % w / w, or even in the range of from 10% to 30 % w / w of one or more monomeric species that are a monomer compound A as defined above. Suitably, the monomer comprises in the range of from 0% to 90 % w / w, optionally in the range of from 5% to 50 % w / w, or even in the range of from 10% to 30 % w / w of one or more monomeric species that are a monomer compound B as defined above. Suitably, the monomer comprises in the range of from 0% to 90 % w / w, optionally in the range of from 5% to 50 % w / w, or even in the range of from 10% to 30 % w / w of one or more monomeric species that are a monomer compound A or monomer compound B as defined above. The method according to the second aspect of the invention may be computer implemented. According to a fourth aspect of the invention, there is provided a computer program comprising instructions which when the program is executed by a computer, cause the computer to carry out the method of the second aspect of the invention. 29 According to a fifth aspect, there is provided a data processing system comprising means for carrying out the method of the second aspect of the invention. Optionally, a plasma deposition apparatus according to the first aspect of the invention or a plasma deposition chamber according to the second aspect of the invention may include a data processing system according to the fifth aspect of the invention. According to a sixth aspect, there is provided a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry the method of the second or third aspect of the invention. A seventh aspect of the invention provides a temperature-controlled electrode for a plasma deposition chamber, the electrode comprising a channel for a temperature control fluid defined by an array of electrode elements. Suitably, the electrode elements may comprise pipes. Optionally, the electrode may comprise a plurality of posts for mounting the electrode to a wall of a plasma deposition chamber. Conveniently, the posts may comprise a power connection, a temperature control fluid connection, or both. Optional features of the electrode or a pair thereof may be as defined in respect of the electrode(s) in the first and second aspects of the invention. An eighth aspect of the invention provides a monomer delivery element for a plasma deposition chamber comprising: a wall element; an array of inlet holes in the wall element; and one or more channels for receiving and channelling monomer vapour to the inlet holes. Suitably, the monomer delivery element may comprise a removable monomer delivery plate optionally mountable flush with the wall element, wherein the inlet holes are formed in the monomer delivery plate. Advantageously, the monomer delivery element may comprise a plurality of feed channels for feeding monomer to the array of inlet holes. Optionally, the plurality of feed channels may be regularly spaced or symmetrical. Suitably, the monomer delivery may comprise a monomer delivery control mechanism configured such that the rate of monomer delivery through at least first and second ones of the feed channels can be independently controlled. Optional features of the monomer delivery element may be as defined in respect of the monomer delivery system in the first and second aspects of the invention. 30 Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprises”, mean “including but not limited to”, and do not exclude other components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Preferred features of each aspect of the invention may be as described in connection with any of the other aspects. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the clauses, claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a plasma deposition apparatus in accordance with an embodiment of the invention; Figure 2 is a schematic sectional view of a plasma deposition chamber of the apparatus of Figure 1; Figure 3A and 3B show top and bottom views respectively of an upper element of the deposition chamber of Figure 2; and Figure 4 is a perspective view of central elements of the plasma deposition apparatus of Figure 1; and Figure 5 is a sectional view of a standardised circuit board immersed in a beaker of tap water for testing coating resistance. DETAILED DESCRIPTION With reference to Figure 1, a plasma deposition apparatus 2 in accordance with an embodiment of the invention comprises a plasma deposition chamber 4 and first and second load lock chambers 6, 8. The plasma deposition chamber 4 and the first and second load lock chambers 6, 8 are operated and controlled via a data processing system 10. The data processing system 10 comprises processing and storage elements 12, 14 and is connected to relevant components of the deposition chamber 4 and load lock chambers 6, 8 via suitable connections (not 31 shown). For example, the data processing system 12 may comprise a combination of one or more processors and a memory storing instructions for operation of the plasma deposition chamber and load lock chambers. In this embodiment, the apparatus 2 is configured for pass-through operation, with items (not shown) entering the first load lock chamber 6, being passed from there into the plasma deposition chamber 4 for coating with a plasma deposited polymeric coating, and then being removed via the second load lock chamber 8. However, the apparatus 2 can also be used in other modes of operation, or modified, as will be described. Referring now also to Figure 2, the plasma deposition chamber 4 has an internal volume of about 120 litres and is designed for controlled and rapid plasma deposition of polymeric coatings onto items precisely located within a narrow deposition zone 16 in the chamber. The deposition chamber 4 is generally cuboid, formed of walls of machined metal with an oblong cross-section. The deposition chamber 4 has major upper and lower walls 18, 20, and minor left, right, front and rear walls. Furthermore, it is longer than it is wide. The front and rear walls 22, 24 comprise slot-shaped front and rear sealable openings 23, 25 respectively that allow items to be passed into and out of the deposition chamber. The deposition chamber 4 is formed of separable upper, middle and lower chamber elements 4U, 4M, 4L, with the upper and lower chamber elements being mirrored in structure. This facilitates construction and allows additional access to the internals of the chamber 4 for maintenance. The elements of the chamber are sealed together by clamping. The internals of the deposition chamber are pressure controlled. The deposition chamber 4 comprises a pressure control system 26 comprising a vacuum pump 28 for cycling the internals of the chamber 4 to sub-atmospheric pressure. For plasma deposition of polymeric coatings, the chamber 4 comprises a monomer delivery system 30 for delivering monomer into the chamber 4, and first and second electrodes 32, 34 for generating a plasma comprising monomer delivered via the monomer delivery system 30 within a cavity 36 bounded by the electrodes. The monomer delivery system 30 and electrodes 32, 34 are formed in the mirrored upper and lower chamber elements 44U, 4L. Referring now additionally to Figure 3A, an internal side of the upper chamber element 4U comprises a monomer distribution 36 plate with an array of inlet holes 37 formed therein. The monomer distribution plate 36 spans a majority of an upper internal 38 wall of the chamber 4 and is flush therewith. 32 The plate 36 is removably mounted to facilitate maintenance and, referring now also to Figure 3B, is connected to six monomer feed channels 40 formed within the upper chamber element. However, any suitable number of monomer feed channels may be achieved as desired. The monomer feed channels 40 in this embodiment are regularly spaced in opposed rows in a rectangular configuration. This aids consistent and controlled monomer delivery. The monomer feed channels 40 are connected to a source of monomer vapour (not shown) to allow delivery of monomer vapour into the deposition chamber 4 at a controlled rate via the inlet holes. The monomer delivery system 30 comprises a monomer delivery control mechanism 42, which allows a rate of monomer delivery through each channel 40 to be independently controlled, for example with the help of one or more valves associated with each channel 40. In this manner, even more precise control of monomer delivery becomes possible. In addition to the monomer delivery system 30, the upper chamber element 4U comprises temperature control channels 44 through which a temperature control fluid such as water (not shown) can be circulated from a heating system 46. In this manner, the temperature of the monomer distribution plate 36 and the upper wall 38 as a whole can be controlled. Since the upper and lower chamber elements 4U, 4L are mirrored, the lower chamber element 4L also comprises a monomer distribution plate 38, temperature control channels 44 and six monomer channels 40 of the same structure. It will be appreciated, that the monomer delivery system 30 as a whole is thus symmetrical about a central plane of the deposition chamber 4. The first and second electrodes 32, 34 are symmetrically opposed about an electrode cavity 36 central within the chamber 4, in this embodiment at a distance to each other of about 45 mm, though other distances may be appropriate depending on the product to be coated. An upper electrode 32 is mounted on the upper chamber element 4U and a lower electrode 34 is mounted on the lower chamber element 4L. Referring again to Figure 3A, the upper electrode 32 comprises four posts 48, spaced in a rectangular configuration, mounting the electrode 32 to the upper chamber wall 38 formed by the upper chamber element 4U. The posts 48 comprise conductive metallic pipes 50 and are connected to corners of a rectangular main body 52 of the electrode, which is offset from the chamber wall 38 and can be supplied with power and a temperature control fluid via the posts 48. The body 52 of the electrode is formed by an array of conductive metallic pipes 50 connected via manifolds 54, through which temperature control fluid supplied via the posts 33 48 can be circulated to control the temperature of the electrode 32. There are gaps in the electrode body 52, between the pipes 50. An RF power supply (not shown) is connected via each of the four posts 48 so that a voltage can be applied to the electrode body 52. Furthermore, the apparatus 2 comprises a heating system 46 in fluid communication with the posts 48 such that temperature control fluid, which may conveniently be water, is provided through two of the posts 48 and returned via the other two 48. The feed is shown with full lines in figure 2 with the return shown in dashed lines. The regular spacing of the posts 48 in a rectangular configuration aids delivery of consistent and controlled power and heating fluid to the electrode 32. The upper electrode 32 is mounted over the monomer delivery plate 36. The majority of the inlet holes 37 of the monomer delivery system 30 is within a lateral boundary of the electrode 32, spanning the majority of the electrode body 52 in a symmetrical fashion. Due to the gaps between the pipes 50, monomer delivered through the inlet holes 37 can pass through the electrode body 52 of the upper electrode 32. The lower electrode 34 mirrors the upper electrode 32 in structure and positioning and is mounted on the lower chamber element 4L. It will be appreciated, that the electrode arrangement as a whole is thus symmetrical about a central plane of the deposition chamber 4. Referring again to Figure 1, to enable a high degree of control over deposition, which has in turn been found to facilitate rapid deposition, the deposition chamber 4 comprises a structure in the form of a transport mechanism 54 for locating items in a deposition zone 16 between the electrodes 32, 34, in the electrode cavity 36. The deposition zone 16 is where items are coated in the deposition chamber 4. The deposition zone 16 may be defined by lateral boundaries of the electrodes 32, 34 and extend from a central imaginary plane between the electrodes 32,34 towards the electrodes. The extent of the deposition zone 16 can depend on the items to be coated, though for consistency of deposition, extending no more than two thirds of the way to the electrodes 32, 34 is preferable. Conveniently, the transport mechanism 54 can also move items into and out of the deposition chamber 4, and specifically the deposition zone 16, via the front and rear sealable openings 23, 25. 34 With reference to Figure 4 the transport mechanism 54 is on the middle chamber element 4M. Specifically, five rollers 56 are mounted in each of the left and right walls 58, 60 defined by the middle chamber element 4M. However, any suitable number of rollers 56 may be used. The rollers 56 act as locating formations. Each set of rollers 56 is driven by a belt (not shown) housed within the middle chamber element and connected to an electric motor (not shown). The rollers 56 are shaped to transport and locate a frame 62 for supporting items. The frame 62, which may be considered to form part of the transport mechanism 54, has complementary indentations to assist gripping and location by the rollers 56. In such an embodiment, the rollers 56 may include a corresponding feature, such as a ridge, that interfaces with the indentation of the frame 62. The frame 62 may include formations for holding items in a defined position. In this manner, items held by the frame 62 can be accurately located with respect to the rollers 54, and by extension the walls 58, 60 of the chamber and functional elements of the deposition chamber 4, such as the electrodes 32, 34 and monomer delivery system 30. This location facilitates control over deposition onto the items because localised deposition conditions can be more readily predicted and controlled. The plasma deposition apparatus 2 comprises a plurality of such frames 62, which can be used sequentially and re-used once coated items are removed therefrom. The rollers 56 are positioned to locate items along a central plane between the electrodes 32, 34. This further aids predictable, controlled and consistent deposition within a deposition zone 16 equidistant from the electrodes 32, 34. Where non-central positioning is desired this can also be achieved in a controlled manner by a suitably configured frame 62. The electrodes 32, 34 are exposed to the deposition zone 16 within which the frame 62 is located via a clear void. Furthermore, the frame 62 is located in a position where it is substantially parallel to the bodies 52 of the electrodes 32, 34 and the upper and lower walls 38 of the deposition chamber 4, including the monomer delivery plate 36. The location provided by the rollers 56 facilitates consistency, prediction and control of deposition onto items. Furthermore, the frame 62 can be moved into and out of the deposition chamber 4 by the rollers 56 via the slot shaped sealable openings 23, 25, to bring items into and out of the deposition chamber 4 automatically. The sealable openings 23, 25 are controlled by respective gate valves 64, 66. These valves 64, 66 can be brought into an open position to allow a frame 62 of items to pass into or out of the deposition chamber 4, or can be sealed to allow the chamber 4 to be pumped to sub- atmospheric pressure. 35 The plasma deposition chamber 4 comprises a range of features that facilitate predictable, controlled and consistent plasma deposition of polymeric coatings onto items. Furthermore, the walls of the plasma deposition chamber 4 and the electrodes 32, 34 are temperature controlled. It has been found possible to achieve significantly higher deposition rates and significantly shorter processing times whilst achieving comparable or improved coating quality. In the plasma deposition apparatus 4 of this embodiment, the plasma deposition chamber 4 is flanked by the first and second load lock chambers 6, 8. The presence of the load lock chambers 6, 8 allows pressure cycling to be eliminated as a rate determining step. The first and second load lock chambers 6, 8 are substantially identical. Each load lock chamber 6, 8 comprises walls of machined metal defining chamber internals and front and rear sealable openings 68, 70. The rear opening 70 of the first load lock chamber 6 is connected to the gate valve 64 at the front opening of the deposition chamber 4 and the front opening 68 of the second load lock chamber 8 is connected to the gate valve 66 at the rear of the deposition chamber 4. Each load lock chamber 6, 8 comprises a conventional pressure control system (not shown) comprising a vacuum pump for cycling the internals of the chamber 6, 8 to sub-atmospheric pressure. The load lock chambers 6, 8 also comprise a transport mechanism 54. Conveniently, the load lock chambers can comprise middle chamber 6M, 8M elements that are identical to the middle chamber element of the plasma deposition chamber. Thus, the load lock chambers 6, 8 each comprise first and second sets of driven rollers 56. The rollers 56 of the load lock chambers and of the deposition chamber 4 are at the same height, and rollers 56 are provided near the openings 23, 25, 68, 70 of the chambers 4, 6, 8. The transport mechanisms 54 of the chambers can convey frames 62 holding items from the first load lock chamber 6 into the deposition chamber 4, and from the deposition chamber 4 into the second load lock chamber 8. This is facilitated by frames 62 of a length that allows bridging of the gate valves 64, 66. Upper and lower chamber elements 6U, 6L, 8U, 8L of the load lock chambers 6, 8 differ from the upper and lower chamber elements 4U, 4L of the deposition chamber 4 in that no electrodes or monomer delivery system are provided. The load lock chambers 6, 8 allow pressure cycling time to be reduced or eliminated as a factor in overall processing time. For example, the plasma deposition chamber 4 may be kept at sub-atmospheric pressure, with the load lock chambers 6, 8 are pressure cycled to 36 allow loading and unloading of items. Pressure cycling of the load lock chambers 6, 8 may then occur concurrently with plasma deposition in the plasma deposition chamber 4, saving time. The plasma deposition chamber 4 and the first and second load lock chambers 6, 8 may be operated or controlled as desired by configuring the data processing system 10. Numerous different modes of operation are achievable. Furthermore, it will be appreciated that numerous modifications and changes can be made the plasma deposition apparatus 2 without departing from the scope of the invention. The plasma deposition apparatus 2 can be used for plasma deposition of polymeric coatings onto items. Parameters of such a process may be chosen consistent with particular objectives. However, as aforesaid, it has been found that the plasma deposition chamber is capable of achieving high deposition rates and significantly shorter processing times. In one embodiment of a process, items are processed using only the plasma deposition chamber 4, with the load locks 6, 8 removed, in a batched manner involving the following steps: A. pushing a frame with items located and affixed thereon via the front or rear opening of the deposition chamber into the deposition chamber; B. locating the frame between the electrodes of the plasma deposition chamber using the rollers of the plasma deposition chamber; C. pumping the plasma deposition chamber to sub-atmospheric pressure; D. performing a plasma deposition process by delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the items E. bringing the plasma deposition chamber back to atmospheric pressure; and F. removing the frame with the items from the plasma deposition chamber via the front or rear opening. For such operation, the plasma deposition chamber 4 could conveniently be embodied with only a single opening. The rollers 56 could also be replaced with a non-actuated support capable of locating items. In another embodiment of a process, items are processed continuously with the plasma deposition chamber 4 being maintained at sub-atmospheric pressure throughout by: 37 I. pushing a frame with items located and affixed thereon via the front opening of the first load lock chamber onto the rollers in the first load lock chamber; II. pumping the first and second load lock chambers to sub-atmospheric pressure; III. driving the rollers of the first load lock chamber and the rollers of the plasma deposition chamber to move the frame into the plasma deposition chamber; IV. performing a plasma deposition process by delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the items, and simultaneously with V, bringing the first load lock chamber to atmospheric pressure and loading the next frame with items according to step I V. driving the rollers of the plasma deposition chamber and the rollers of the second load lock chamber to move the frame into the second load lock chamber under sub-atmospheric pressure; VI. running a cleaning cycle in the plasma deposition chamber; VII. bringing the second load lock chambers to atmospheric pressure; VIII. removing the frame with the items from the second load lock chamber via the rear opening and pumping the chamber back down to sub-atmospheric pressure The gate valves 64, 66 are operated to ensure that sub-atmospheric pressure is maintained in the plasma deposition chamber 4. It will be appreciated that, as this is a continuous process, a number of these steps can be coordinated to overlap, saving time. Notably, steps IV and VI can occur at the same time as steps I and II and / or steps VII and VIII. The data processing system 10 can be configured accordingly. Many other modes of operation are also conceivable. For example, it is possible to employ only a single load lock, or a sub-atmospheric buffer chamber connected to one or more load lock chambers or a sub-atmospheric assembly line. There are also many different ways of performing a plasma deposition process by delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the items. In one example provided for illustration only, the following deposition conditions were employed for a rapid deposition of a water repellent coating. Example 1 38 A mixture of benzyl acrylate (85% w / w) and crosslinking agent divinyl adipate (15% w / w), was employed as monomer for plasma deposition of a protective polymeric coating onto standardised circuit boards. The resultant coatings were tested and compared. Deposition Frames bearing the circuit boards were continuously processed by the plasma deposition apparatus of Figures 1 to 4, based on steps I to VIII above. The following parameters were employed for step IV: - sub atmospheric pressure: 40 mTorr - electrode target temperature: 50 °C - chamber wall target temperature: 50 °C - oxygen plasma at 300 W per electrode at RF 13.56 MHz for 5 seconds with an oxygen flow rate of 800 sccm - deposition plasma with monomer: 80s o monomer flow rate: 4 cc / min o power 150 W per electrode at RF 13.56MHz, pulsed at duty cycle of 4 % and a frequency of 800 Hz The following parameters were employed for step VI: - sub atmospheric pressure: 1500 mTorr - electrode target temperature 50 °C - chamber wall target temperature 50 °C - Oxygen flow 2000 sccm - cleaning time: 30 s - power at 2000 W per electrode at RF 13.56MHz, continuous power The total processing time for each frame was 106 seconds. On account of the short processing time, it was possible to utilise a relatively high target temperature for the chamber walls (which reduced reduce stray deposition and the need for cleaning) whilst still achieving a high deposition rate on the items. 39 Analysis of coatings Referring now to Figure 5, the coatings on the circuit boards were analysed with an electrical test representative of achieving IPX7 threshold in a device. The effectiveness of a coating can be determined by measuring its electrical resistance at a fixed voltage when submerged in water 100 for a set time period; for example, applying a voltage of 8V to the coating of a circuit board which is submerged in water for 13 minutes. A test method has been devised to evaluate the ability of different coatings to provide an electrical barrier on printed circuit boards and predict the ability of a smart phone containing the printed circuit board to pass the IEC 6052914.2.7 (IPX7) test. The method is designed to be used with tap water. This test involves measuring the current voltage (IV) characteristics of a standardised printed circuit board (PCB) in water. The PCB has been designed with spacing of 0.5 mm between electrodes to allow assessment of when electrochemical migration occurs across the tracks in water. The degree of electrochemical activity is quantified by measuring current flow; low current flow is indicative of a good quality coating. The method has proved to be extremely effective at discriminating between different coatings. The coated PCB 100 to be tested is placed into a beaker 102 of water 104 and connected to the electrical test apparatus via connections 106, 108 as shown Figure 5. The board 100 is centred horizontally and vertically in the beaker 102 to minimise effects of local ion concentration (vertical location of the board is very important; water level should be to the blue line). When the PCB is connected, the power source is set to the desired voltage and the current is immediately monitored. The voltage applied was 8V and the PCB was held at the set voltage for 13 minutes, with the current being monitored continuously during this period. Coatings having a resistance value of 1x107Ohms or higher in this test have been found to be effective barrier coatings in the context of aiming to pass an IPX7 test. A resistance value of 1x107Ohms or higher was achieved on each test. Thus, the boards produced by Example 1 were coated with a highly effective barrier coating. Reference For comparison, a coating with the same level of barrier performance was produced using the same monomer system but a batch process employing a conventional 450 litre plasma deposition chamber. Features of such a conventional chamber include: - Electrodes form part of a multi-layered shelving for holding items 40 - Monomer delivery from front of chamber - Power levels typically 100 – 6000W - Items placed within a shelf system in several layers Example 1 achieved a considerably higher throughput, as can be seen from Table 1: Table 1 * Includes transfer time ** Actual clean process 10x longer but only required after 10 processes The following numbered clauses also disclose aspects and embodiments of the invention: 1. A plasma deposition apparatus for applying a plasma deposited polymeric coating to items, the apparatus comprising: a plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber, a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system, and a structure for locating items between the electrodes; and a load lock chamber communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber. 2. The plasma deposition apparatus of clause 1, wherein the structure is arranged to locate items in a deposition zone within an electrode cavity bounded by the electrodes. 3. The plasma deposition apparatus of clause 2, wherein the electrode cavity is central within the deposition chamber. 41 4. The plasma deposition apparatus of clause 2 or clause 3, wherein all electrodes of the deposition chamber bound the electrode cavity and the electrode cavity is the sole electrode cavity of the deposition chamber. 5. The plasma deposition apparatus of any of clauses 2 to 4, wherein the electrodes are exposed to the deposition zone. 6. The plasma deposition apparatus of any of clauses 2 to 5, wherein a lateral boundary of the electrodes is within or in register with a lateral boundary of the deposition zone. 7. The plasma deposition apparatus of any of clauses 2 to 6, wherein the deposition zone extends from an imaginary plane or axis between the electrodes towards the electrodes, the imaginary plane or axis optionally being central to the electrode cavity. 8. The plasma deposition apparatus of clause 7, wherein the deposition zone extends no more than two thirds, or optionally no more than halfway to the electrodes. 9. The plasma deposition apparatus of clause 7 or clause 8, wherein the imaginary plane or axis is parallel to or coincides with a plane or axis of symmetry associated with one or more of: (i) the electrodes; (ii) the monomer delivery system; and (iii) the chamber. 10. The plasma deposition apparatus of any of clauses 7 to 9, wherein the imaginary plane or axis is parallel to one or more electrode faces of the electrodes. 11. The plasma deposition apparatus of any of clauses 2 to 10, wherein the structure is arranged to locate items centrally within the deposition zone. 12. The plasma deposition apparatus of any of clauses 2 to 11, wherein the structure is arranged to locate a plurality of items in the deposition zone concurrently, optionally in coplanar positions. 13. The plasma deposition apparatus of any preceding clause, wherein the structure is arranged to locate items within a single plane, optionally along a central plane between the electrodes. 14. The plasma deposition apparatus of any preceding clause, wherein the structure is arranged to locate items in an unstacked or non-overlapping configuration, optionally a single coplanar configuration. 15. The plasma deposition apparatus of any preceding clause, wherein the structure is arranged to locate items in a position where they are directly exposed to the electrodes, optionally such that items to be coated are located such that an upper surface of the item is 42 exposed to an upper electrode of the deposition chamber and a lower surface of the item is exposed to a lower electrode of the deposition chamber. 16. The plasma deposition apparatus of any preceding clause, wherein the structure comprises a locating indentation or formation on or integral with a wall of the deposition chamber. 17. The plasma deposition apparatus of any preceding clause, wherein the structure comprises a transport mechanism for moving and locating items between the electrodes. 18. The plasma deposition apparatus of clause 17, wherein the transport mechanism is also for moving items away from a position between the electrodes. 19. The plasma deposition apparatus of clause 17 or clause 18, wherein the transport mechanism comprises one or more actuators attached to one or more walls of the deposition chamber. 20. The plasma deposition apparatus of clause 19, wherein the actuators comprise a plurality of driven rollers. 21. The plasma deposition apparatus of clause 19 or clause 20, wherein the one or more actuators comprise first and second sets of rollers on opposed chamber walls. 22. The plasma deposition apparatus of any of clauses 19 to 21, wherein the transport mechanism comprises a drive for driving the one or more actuators. 23. The plasma deposition apparatus of any of clauses 17 to 22, wherein the transport mechanism is capable of moving items beyond an opening of the deposition chamber and optionally is capable of moving items into the deposition chamber from outside the deposition chamber. 24. The plasma deposition apparatus of any preceding clause, wherein the structure comprises a mobile support locatable in the deposition chamber to support and locate one or more items between the electrodes. 25. The plasma deposition apparatus of clause 24, wherein the mobile support comprises an indentation or formation for engaging an indentation or formation mounted on or integral with a wall of the deposition chamber, to locate the support in the deposition chamber. 26. The plasma deposition apparatus of clause 25, wherein the mobile support comprises a frame, the frame optionally having one or more indentations or formations for locating one or more items and optionally comprising a fixing for affixing an item thereto. 43 27. The plasma deposition apparatus of any of clauses 24 to 26 wherein the structure comprises a transport mechanism, optionally as defined in any of clauses 17 to 22, wherein the transport mechanism is co-operable with the support to move and locate the support to bring items into and out of position between the electrodes. 28. The plasma deposition apparatus of clause 27, wherein the support comprises one or more indentations or formations for engaging the transport mechanism. 29. The plasma deposition apparatus of clause 27 or clause 28, wherein the support is co- operable with the transport mechanism to allow the support to be moved by the transport mechanism from beyond an opening of the chamber. 30. The plasma deposition apparatus of any preceding clause, wherein the electrodes are identical in structure. 31. The plasma deposition apparatus of any preceding clause wherein the electrodes are arranged symmetrically about a deposition zone in which the structure is arranged to locate items. 32. The plasma deposition apparatus of any preceding clause wherein the electrodes comprise or consist of a pair of opposed electrodes, optionally mirrored, optionally wherein the electrodes are at a distance from each other in the range of from 20 to 200 mm, for example in the range of from 30 to 150 mm, or in the range of from 40 to 100 mm. 33. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes comprises a plurality of power connections, the power connections optionally being regularly spaced or symmetrical. 34. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes comprises gaps, optionally wherein the gaps are in a regular pattern. 35. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes comprises a major face facing a deposition zone in which the structure is arranged to locate items. 36. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes comprise an array of connected electrode elements, the electrode elements optionally comprising pipes. 37. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes is mounted to a wall of the chamber with a body of the electrode offset from the wall of the chamber. 44 38. The plasma deposition apparatus of any preceding clause wherein one or more of the electrodes comprises a plurality of posts for mounting the electrode to a wall of the chamber. 39. The plasma deposition apparatus of clause 38, wherein the posts comprise a power connection, a temperature control fluid connection, or both. 40. The plasma deposition apparatus of any preceding clause, wherein the electrodes are mounted on major walls of the chamber. 41. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber is oblong in cross-section and has a minor and a major cross-sectional axis and the electrodes are mounted walls of the chamber that are parallel with the major cross- sectional axis of the chamber. 42. The plasma deposition apparatus of any preceding clause, wherein one or more of the electrodes has a temperature control mechanism. 43. The plasma deposition apparatus of clause 42, wherein the temperature control mechanism comprises a channel within the electrode for receiving a temperature control fluid. 44. The plasma deposition apparatus of clause 43, wherein the channel is defined by an array of electrode elements, optionally comprising pipes. 45. The plasma deposition apparatus of any preceding clause, wherein the monomer delivery system comprises a plurality of inlet holes. 46. The plasma deposition apparatus of clause 45, wherein the monomer delivery system comprises inlet holes on an opposed side of one or more of the electrodes relative to a deposition zone in which the structure is arranged to locate items. 47. The plasma deposition apparatus of clause 46, wherein all inlet holes of the monomer delivery system are on an opposed side of one or more of the electrodes relative to the deposition zone. 48. The plasma deposition apparatus of any of clauses 45 to 47, wherein the inlet holes are formed in a monomer delivery plate associated with one or more walls of the plasma deposition chamber. 49. The plasma deposition apparatus of clause 48, wherein the monomer delivery plate is flush with one or more walls of the chamber. 45 50. The plasma deposition apparatus of clause 48 or clause 49, wherein the monomer delivery plate is associated with one or more walls of the chamber comprising a temperature control system. 51. The plasma deposition apparatus of any of clauses 48 to 50 wherein the chamber is oblong in cross-section and has a minor and a major cross-sectional axis and the monomer delivery plate is mounted on a wall of the chamber that is parallel with the major cross- sectional axis of the chamber. 52. The plasma deposition apparatus of any of clauses 45 to 51, wherein a majority of the inlet holes is within a lateral boundary of one of the electrodes. 53. The plasma deposition apparatus of any of clauses 45 to 52, wherein the inlet holes are arranged symmetrically about a deposition zone in which the structure is arranged to locate items. 54. The plasma deposition apparatus of any of clauses 45 to 52 wherein the inlet holes comprise or consist of opposed arrays of inlet holes, optionally mirrored. 55. The plasma deposition apparatus of any of clauses 45 to 54, wherein the monomer delivery system comprises a plurality of feed channels for feeding monomer to an array of inlet holes, the feed channels optionally being regularly spaced or symmetrical. 56. The plasma deposition apparatus of clause 55, comprising a monomer delivery control mechanism configured such that the rate of monomer delivery through at least first and second ones of the feed channels can be independently controlled. 57. The plasma deposition apparatus of any preceding clause, wherein the monomer delivery system comprises a source of monomer vapour. 58. The plasma deposition apparatus of any preceding clause, wherein the plasma deposition chamber comprises walls defining internals of greater width and length than height, with an opening at each longitudinal end. 59. The plasma deposition apparatus of any preceding clause, comprising one or more temperature-controlled walls, optionally temperature controlled by a temperature control mechanism comprising a channel for receiving a temperature control fluid. 60. The plasma deposition apparatus of clause 59, wherein the deposition chamber is oblong in cross-section and has a minor and a major cross-sectional axis and one or more major walls of the chamber parallel with the major cross-sectional axis of the chamber is temperature controlled. 46 61. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber has a volume of less than 300 litres, optionally in the range of from 25 to 200 litres, such as in the range of from 75 to 150 litres. 62. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber comprises a RF power supply for powering the electrodes. 63. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber comprises a pressure control system for cycling the internals of the deposition chamber to sub-atmospheric pressure. 64. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber comprises a sealable opening for receiving and / or removing items. 65. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber comprises a plurality of sealable openings for receiving and / or removing items. 66. The plasma deposition apparatus of any preceding clause, wherein the deposition chamber is a pass-through chamber comprising a first sealable opening for receiving items and a second sealable opening for removing items. 67. The plasma deposition apparatus of any preceding clause, wherein one or more sealable openings of the plasma deposition chamber are controlled by a gate valve. 68. The plasma deposition apparatus of any preceding clause, wherein the load lock chamber comprises a pressure control system for cycling the internals of the load lock chamber to sub-atmospheric pressure. 69. The plasma deposition apparatus of any preceding clause, wherein the wherein the load lock is communicable with the plasma deposition chamber via a sealable opening, optionally comprising a gate valve. 70. The plasma deposition apparatus of any preceding clause, wherein the load lock is in direct communication with the plasma deposition chamber. 71. The plasma deposition apparatus of any preceding clause, wherein the plasma deposition apparatus is a pass through apparatus comprising a first load lock communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber and a second load lock communicable with the plasma deposition chamber to remove items from the plasma deposition chamber. 47 72. The plasma deposition apparatus of clause 71, wherein the first and second load locks are in communication with the plasma deposition chamber via sealable openings at opposed ends of the plasma deposition chamber and optionally are of the same structure. 73. The plasma deposition apparatus of any preceding clause, wherein the load lock chamber comprises a transport mechanism for moving items into the deposition chamber. 74. The plasma deposition apparatus of any preceding clause, wherein the load lock chamber comprises a transport mechanism for moving items out of the deposition chamber. 75. The plasma deposition apparatus of clause 73 or clause 74 wherein the transport mechanism comprises one or more actuators attached to one or more walls of the load lock chamber. 76. The plasma deposition apparatus of clause 75, wherein the actuators comprise a plurality of driven rollers. 77. The plasma deposition apparatus of clause 75 or clause 76, wherein the one or more actuators comprise first and second sets of rollers on opposed chamber walls. 78. The plasma deposition apparatus of any of clauses 75 to 77, wherein the transport mechanism comprises a drive for driving the one or more actuators. 79. The plasma deposition apparatus of any of clauses 75 to 78, wherein the transport mechanism is capable of moving items beyond an opening of the load lock chamber and optionally is capable of moving items into the load lock chamber from outside the load lock chamber. 80. The plasma deposition apparatus of any preceding clause, wherein complementary transport mechanisms of the deposition chamber and the load lock chamber cooperate to bridge an opening or gap between the chambers so as to be able to move items into or out of the deposition chamber via the load lock chamber. 81. The plasma deposition apparatus according to any preceding clause, comprising separate skids for supporting the deposition chamber and the load lock chamber. 82. The plasma deposition apparatus according to any preceding clause, integrated into a continuous assembly line and be configured to coat items proceeding in the assembly line in a continuous manner. 83. A plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber; 48 a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system; and a structure for locating items between the electrodes. 84. The plasma deposition chamber of clause 83, which is as further defined in any of clauses 2 to 67. 85. A method of applying a plasma deposited polymeric coating to an item with a plasma deposition chamber or plasma deposition apparatus according to any preceding clause, the method comprising: locating the item between the electrodes of the plasma deposition chamber using the structure of the plasma deposition chamber; and delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the item. 86. A method of applying a plasma deposited polymeric coating to a plurality of items with a plasma deposition apparatus according to any of clauses 1 to 82, the method comprising: a) placing the item into the load lock chamber of the apparatus; b) moving the item from the load lock chamber into the plasma deposition chamber of the apparatus; c) locating the item between the electrodes of the plasma deposition chamber using the structure of the plasma deposition chamber; d) delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the item; and e) moving the item out of the deposition chamber. 87. The method of clause 86, comprising applying a plasma deposited coating to a plurality of items in a continuous manner by repeating a) to e) whilst maintaining the plasma deposition chamber at sub-atmospheric pressure. 88. The method of clause 86 or clause 87, wherein e) comprises moving items out of the plasma deposition chamber via a second load lock chamber. 49 89. The method of any of clauses 86 to 88 wherein the load lock chamber is loaded with an item and brought to sub-atmospheric pressure whilst a coating is concurrently applied to another item in the plasma deposition chamber. 90. The method of any of clauses 86 to 89 wherein an item is be removed via a load lock whilst a coating is concurrently applied to another item in the plasma deposition chamber. 91. The method of any of clauses 86 to 90, wherein moving the item comprises activating a transport mechanism of the apparatus. 92. The method of any of clauses 85 to 91, comprising applying the plasma deposited coating in the deposition chamber in under 600 seconds, optionally in under 300 seconds, or indeed in under 200 seconds. 93. The method of any of clauses 85 to 92, comprising maintaining chamber walls of the plasma deposition chamber at a temperature in the range of from 40 to 60 degrees C. 94. The method of any of clauses 85 to 93, comprising delivering monomer to the plasma deposition chamber at a rate of at most 15 per mL / min of chamber volume. 95. The method of any of clauses 85 to 94, comprising applying a pulsed power to the electrodes, optionally with a duty cycle in the range of from 0.1 to 10%. 96. The method of any of clauses 85 to 95, wherein the power density in the deposition chamber is set at 0.5 - 60 W / litre of chamber volume. 97. The method of any of clauses 85 to 96, wherein the item comprises an electronic device or component thereof, optionally a printed circuit board. 98. The method of any of clauses 85 to 97 wherein locating the item between the electrodes of the plasma deposition chamber comprises locating the item centrally within a deposition zone of the plasma deposition chamber. 99. The method of any of clauses 85 to 98 comprising coating a plurality of items concurrently by locating a plurality of items between the electrodes of the plasma deposition chamber, optionally in a coplanar arrangement. 100. The method of clause 99 comprising locating items within or along only one plane within a deposition zone of the deposition chamber, optionally a central plane between the electrodes. 101. The method of clause 99 or clause 100 comprising locating items in an unstacked or non-overlapping configuration during coating, optionally a single coplanar configuration. 50 102. The method of any of clauses 99 to 101, comprising locating items in a position where they are directly exposed to the electrodes, optionally such that all items to be concurrently coated are located such that an upper surface of the item is exposed to an upper electrode of the deposition chamber and a lower surface of the item is exposed to a lower electrode of the deposition chamber. 103. The method of any of clauses 85 to 102 comprising placing one or more items to be coated in a frame of a transport mechanism of the deposition chamber. 104. The method of any of clauses 85 to 103 wherein the monomer comprises one or more unsaturated monomeric species. 105. The method of clause 104, wherein the one or more unsaturated species comprise a monomer compound A comprising (i) an aromatic moiety and (ii) a carbonyl moiety. 106. The method of clause 105, wherein the monomer compound A comprises moiety (α) or (β): wherein each R is independently selected from hydrogen, optionally substituted branched or straight chain alkyl, or optionally substituted cycloalkyl. 107. The method of clause 105 or 106, wherein the monomer compound A is a compound of formula (I): wherein Q is selected from structures (Qa), (Qb), (Qc) and (Qd): 51

[0041] wherein each of R1, R2and R3is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, or optionally substituted C3-C8cycloalkyl; Z is a direct bond or a linker moiety; and Ar is an optionally substituted aromatic moiety. 108. The method of clause 107, wherein Q is selected from structures (Qc) and (Qd) and wherein each of R1, R2and R3is independently selected from hydrogen, methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl, preferably wherein R3is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3- methylpentyl and R2and R1are hydrogen. 109. The method of clause 105 or 106, wherein the monomer compound A is a compound of formula (I): wherein Q is selected from structures (Qa) and (Qb): 52 wherein each of R1, R2and R3is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, or optionally substituted C3-C8cycloalkyl; Z is a direct bond or a linker moiety; and Ar is an optionally substituted aromatic moiety. 110. The method of clause 109, wherein each of R1, R2and R3is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl. 111. The method of clause 110, wherein each of R1, R2and R3is hydrogen. 112. The method of any of clauses 109 to 112, wherein the monomer compound A of formula (I) is a compound of formula (Ia): 113. The method of any of clauses 106 to 112, wherein Z has the formula: -(CH2)n- where n is an integer from 0 to 27. 114. The method of clause 113, wherein n is an integer from 0 to 2. 115. The method of clause 114, wherein n is 1. 53 116. The method of any of clauses 106 to 115, wherein Ar is an optionally substituted monocyclic aromatic moiety or an optionally substituted bicyclic aromatic moiety.

[0042] 117. The method of clause 116, wherein Ar is an optionally substituted C3-C12aryl group.

[0043] 118. The method of clause 117, wherein Ar is optionally substituted phenyl.

[0044] 119. The method of any of clauses 105 to 118, wherein the monomer compound A is benzyl acrylate.

[0045] 120. The method of any of clauses 105 to 119, wherein the monomer compound A does not contain any fluorine atoms.

[0046] 121. The method of clause 104, wherein the one or more monomeric species comprise a monomer compound B that has the formula (IV): where R1, R2and R4are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl or halo alkyl or aryl optionally substituted by halo, and R3is selected from: where each X is independently selected from hydrogen, a halogen, optionally substituted branched or straight chain Ci-C6alkyl, halo alkyl or aryl optionally substituted by halo; and ni is an integer from 1 to 27.

[0047] 122. The method of clause 121, wherein ni is in the range of from 1 to 12, and / or wherein the monomer compound B is a compound of formula (IVa):

[0048] 54 (IVa) wherein each of R1, R2, R4, and R5to R10is independently selected from hydrogen or an optionally substituted Ci-C6branched or straight chain alkyl group; each X is independently selected from hydrogen or halogen; a is 0 or 1; b is from 3 to 7; and c is 0 or 1; or wherein the monomer compound B is a compound of formula (IVb): wherein each of Ri, R2, R4, and R5to R10is independently selected from hydrogen or an optionally substituted Ci-C6branched or straight chain alkyl group; each X is independently selected from hydrogen or halogen; a is 0 or 1; b is from 3 to 7; and c is 0 or 1.

[0049] 123. The method of clause 122, wherein each of R1, R2, R4, and R5to R10is independently selected from hydrogen or methyl.

[0050] 124. The method of clause 121 or clause 122, wherein R1and R2are both hydrogen and wherein each of R5to R8is hydrogen.

[0051] 125. The method of any of clauses 121 to 124 wherein each X is H.

[0052] 126. The method of any of clauses 121 to 124, wherein each X is F.

[0053] 127. The method of clause 121, wherein the one or more monomeric species comprise a monomer compound B that has the formula (IVc): where n is from 2 to 10,

[0054] 55 optionally wherein the monomer compound B is selected from 1H,1H,2H,2H- perfluorohexyl acrylate (PFAC4), 1H,1H,2H,2H-perfluorooctyl acrylate (PFAC6), 1H,1H,2H,2H-perfluorodecyl acrylate (PFAC8) and 1H,1H,2H,2H-perfluorododecyl acrylate (PFAC10); or a monomer compound B that has the formula (IVd): where n is from 2 to 10, optionally wherein the monomer compound B is selected from 1H,1H,2H,2H- pefluorohexyl methacrylate (PFMAC4), 1H,1H,2H,2H-perfluorooctyl methacrylate (PFMAC6) and 1H,1H,2H,2H-perfluorodecyl methacrylate (PFMAC8).

[0055] 128. The method of clause 121, wherein the one or more monomeric species comprise a monomer compound B that has the formula (IVe): wherein a and c are each independently 0 or 1, b is from 3 to 7 and n is from 4 to 10, where n=a+b+c+l.

[0056] 129. The method of clause 121, wherein the one or more monomeric species comprise a monomer compound B that has the formula (IVf):

[0057] 56 where n is from 2 to 10, optionally wherein the monomer compound B is selected from ethyl hexyl acrylate, hexyl acrylate, decyl acrylate, lauryl dodecyl acrylate and iso decyl acrylate; or a monomer compound B that has the formula (IVg) :

[0058] 5 where n is from 4 to 12, optionally where R1, R2and R3are each H.

[0059] 130. The method of any of clauses 121 to 129 wherein the monomeric species comprise a further monomer compound A as defined in any of clauses 97 to 112.

[0060] 10 131. The method of any of clauses 104 to 130 wherein the one or more unsaturated monomeric species further comprise a crosslinking reagent.

[0061] 132. The method of clause 131, wherein the crosslinking reagent is independently selected from a compound of formula (II) or (III) :

[0062] 15 wherein

[0063] Y1, Y2, Y3, Y4, Y5, Y6, Y7and Y8are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6alkyl, optionally substituted C1-C6cycloalkyl, and optionally substituted C1-C6aryl; and L is a linker moiety.

[0064] 20 133. The method of clause 132, wherein group L has the formula :

[0065] 57 wherein each Y9is independently selected from a bond, -O-, -O-C(O)-, –C(O)-O-, -Y11-O-C(O)-, -C(O)-O-Y11-, -O-C(O)-Y11-, -Y11-C(O)-O-, -OY11-, and –Y11O-, wherein Y11is an optionally substituted branched, straight chain or cyclic C1-C8alkylene; and Y10is selected from an optionally substituted branched, straight chain or cyclic C1-C8alkylene, arylene, and a siloxane group. 134. The method of any of clauses 131 to 133, wherein the crosslinking reagent is independently selected from divinyl adipate (DVA), 1,4-butanediol divinyl ether (BDVE), 1,4-cyclohexanedimethanol divinyl ether (CDDE), 1,7-octadiene (17OD), 1,2,4- trivinylcyclohexane (TVCH), 1,3-divinyltetramethyldisiloxane (DVTMDS), diallyl 1,4- cyclohexanedicarboxylate (DCHD), glyoxal bis(diallyl acetal) (GBDA), and 1,4-phenylene diacrylate. 135. The method of any of clauses 131 to 134, wherein the crosslinking reagent is divinyl adipate (DVA). 136. The method of any of clauses 131 to 135, wherein the crosslinking reagent does not contain any fluorine atoms. 137. The method of any of clauses 104 to 136 wherein the monomer comprises a single monomeric species that is a monomer compound A as defined in any of clauses 105 to 120. 138. The method of any of clauses 104 to 137 wherein the monomer comprises a single monomeric species that is a monomer compound B as defined in any of clauses 105 to 120. 139. The method of any of clauses 104 to 138 wherein the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a monomer compound A as defined in any of clauses 105 to 120. 140. The method of any of clauses 104 to 138 wherein the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are a monomer compound B as defined in any of clauses 121 to 129. 141. The method of any of clauses 104 to 138 wherein the monomer comprises in the range of from 10% to 100 % w / w, optionally in the range of from 50% to 95 % w / w, or even in the range of from 70% to 90 % w / w of one or more monomeric species that are 58 a monomer compound A as defined in any of clauses 105 to 120 or a monomer compound B as defined in any of clauses 121 to 129. 142. The method of any of clauses 104 to 141 wherein the monomer comprises in the range of from 0% to 90 % w / w, optionally in the range of from 5% to 50 % w / w, or even in the range of from 10% to 30 % w / w of one or more monomeric species that are a crosslinking reagent as defined in any of clauses 130 to 136. 143. The method of any of clauses 85 to 142 which is computer implemented. 144. A computer program comprising instructions which when the program is executed by a computer, cause the computer to carry out a method according to any of clauses 85 to 142. 145. A data processing system comprising means for carrying out a method according to any of clauses 85 to 142. 146. A plasma deposition apparatus or chamber according to any of clauses 1 to 84 comprising a data processing system according to clause 145. 147. A non-transitory computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry a method according to any of clauses 85 to 142. 148. A temperature-controlled electrode for a plasma deposition chamber, the electrode comprising a channel for a temperature control fluid defined by an array of electrode elements. 149. The electrode of clause 148, wherein the electrode elements comprise pipes. 150. The electrode of clause 148 or clause 149 comprising a plurality of posts for mounting the electrode to a wall of a plasma deposition chamber. 151. The electrode of clause 150 wherein the posts comprise a power connection, a temperature control fluid connection or both. 152. A monomer delivery element for a plasma deposition chamber comprising: a wall element; an array of inlet holes in the wall element; and one or more channels for receiving and channelling monomer vapour to the inlet holes. 59 153. The monomer delivery element of clause 152 comprising a removable monomer delivery plate optionally mountable flush with the wall element, wherein the inlet holes are formed in the monomer delivery plate. 154. The monomer delivery element of clause 152 or clause 153 comprising a plurality of feed channels for feeding monomer to the array of inlet holes. 155. The monomer delivery element of clause 154 wherein the plurality of feed channels is regularly spaced or symmetrical. 156. The monomer delivery element of clause 154 or clause 155 comprising a monomer delivery control mechanism configured such that the rate of monomer delivery through at least first and second ones of the feed channels can be independently controlled. 60

Claims

CLAIMS 1. A plasma deposition apparatus for applying a plasma deposited polymeric coating to items, the apparatus comprising: a plasma deposition chamber comprising: a monomer delivery system for delivering monomer into the chamber, a plurality of electrodes in the chamber for generating a plasma comprising monomer delivered via the monomer delivery system, and a structure for locating items between the electrodes; and a load lock chamber communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber.

2. The plasma deposition apparatus of claim 1, wherein the structure is arranged to locate items in a deposition zone within an electrode cavity bounded by the electrodes.

3. The plasma deposition apparatus of claim 2, wherein all electrodes of the deposition chamber bound the electrode cavity and the electrode cavity is the sole electrode cavity of the deposition chamber.

4. The plasma deposition apparatus of any preceding claim, wherein the structure is arranged to locate items within a single plane, optionally along a central plane between the electrodes.

5. The plasma deposition apparatus of any preceding claim, wherein the structure is arranged to locate items in an unstacked or non-overlapping configuration, optionally a single coplanar configuration.

6. The plasma deposition apparatus of any preceding claim, wherein the structure comprises a transport mechanism for moving and locating items between the electrodes.

7. The plasma deposition apparatus of claim 6, wherein the transport mechanism comprises one or more actuators attached to one or more walls of the deposition chamber.

8. The plasma deposition apparatus of claim 7, wherein the actuators comprise a plurality of driven rollers.

9. The plasma deposition apparatus of any preceding claim wherein the electrodes are arranged symmetrically about a deposition zone in which the structure is arranged to locate items. 6110. The plasma deposition apparatus of any preceding claim wherein the electrodes consist of a pair of opposed electrodes, optionally mirrored, optionally wherein the electrodes are at a distance from each other in the range of from 20 to 200 mm, for example in the range of from 30 to 150 mm, or in the range of from 40 to 100 mm.

11. The plasma deposition apparatus of any preceding claim, wherein one or more of the electrodes has a temperature control mechanism.

12. The plasma deposition apparatus any preceding claim, wherein the monomer delivery system comprises inlet holes on an opposed side of one or more of the electrodes relative to a deposition zone in which the structure is arranged to locate items.

13. The plasma deposition apparatus of any preceding claim, comprising one or more temperature-controlled walls, optionally temperature controlled by a temperature control mechanism comprising a channel for receiving a temperature control fluid.

14. The plasma deposition apparatus of any preceding claim, wherein the deposition chamber has a volume of less than 300 litres, optionally in the range of from 25 to 200 litres, such as in the range of from 75 to 150 litres.

15. The plasma deposition apparatus of any preceding claim, wherein the wherein the load lock is communicable with the plasma deposition chamber via a sealable opening, optionally comprising a gate valve.

16. The plasma deposition apparatus of any preceding claim, wherein the plasma deposition apparatus is a pass through apparatus comprising a first load lock communicable with the plasma deposition chamber to introduce items into the plasma deposition chamber and a second load lock communicable with the plasma deposition chamber to remove items from the plasma deposition chamber.

17. The plasma deposition apparatus of claim 16, wherein the first and second load locks are in communication with the plasma deposition chamber via sealable openings at opposed ends of the plasma deposition chamber and optionally are of the same structure.

18. The plasma deposition apparatus of any preceding claim, wherein complementary transport mechanisms of the deposition chamber and the load lock chamber cooperate to bridge an opening or gap between the chambers so as to be able to move items into or out of the deposition chamber via the load lock chamber.

19. A method of applying a plasma deposited polymeric coating to a plurality of items with a plasma deposition apparatus according to any of claims 1 to 18, the method comprising: f) placing the item into the load lock chamber of the apparatus; 62g) moving the item from the load lock chamber into the plasma deposition chamber of the apparatus; h) locating the item between the electrodes of the plasma deposition chamber using the structure of the plasma deposition chamber; i) delivering monomer through the monomer delivery system and applying a voltage to the electrodes to generate a plasma comprising the monomer to apply a coating to the item; and j) moving the item out of the deposition chamber.

20. The method of claim 19, comprising applying a plasma deposited coating to a plurality of items in a continuous manner by repeating a) to e) whilst maintaining the plasma deposition chamber at sub-atmospheric pressure.

21. The method of claim 19 or claim 20, wherein e) comprises moving items out of the plasma deposition chamber via a second load lock chamber.

22. The method of any of claims 19 to 21 comprising locating a plurality of items in an unstacked or non-overlapping configuration during coating, optionally a single coplanar configuration.

23. The method of any of claims 19 to 22, comprising locating all items to be concurrently coated such that an upper surface of the item is exposed to an upper electrode of the deposition chamber and a lower surface of the item is exposed to a lower electrode of the deposition chamber.

24. A computer program comprising instructions which when the program is executed by a computer, cause the computer to carry out a method according to any of claims 19 to 23.

25. A data processing system comprising means for carrying out a method according to any of claims 19 to 23. 63

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